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FAA Grounds 787, Part 11  
User currently offline777ER From New Zealand, joined Dec 2003, 12145 posts, RR: 17
Posted (1 year 6 months 3 weeks 4 days 5 hours ago) and read 26029 times:
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Link to thread #10 FAA Grounds 787, Part 10 (by 777ER Feb 17 2013 in Civil Aviation)#menu209

WARNING: Due to thread 9 going off topic quickly and turning into a 'battle ground', the moderators will be watching this thread frequently and ANY offending/rule breaking posts will be removed. Please respect each others right to have their opinion.

216 replies: All unread, showing first 25:
 
User currently offlinePW100 From Netherlands, joined Jan 2002, 2485 posts, RR: 11
Reply 1, posted (1 year 6 months 3 weeks 4 days 4 hours ago) and read 26026 times:

OK. Recap:

The Nr.1 reason FAA issued the AD (which in effect grounded the 787 fleet) was the fact that Boeing had earlier claimed/demonstrated to a satisfactory level in the design certification, that such an event (battery thermal runaway) would happen less than once in a million hours. Once such an event happened twice in 50,000 hours, or less than two weeks apart, the whole certification basis of the 787 Type Certificate fell away, and the FAA had no other option.

Basically, the AD says Boeing has to redo this part of the design certification, and demonstrate how they will meet their earlier claims, and more importantly, how they can prove their assumptions. And you can count on it that this time there will be a lot more scrutiny than the first time around, when Boeing had a significant level of “delegated authority” to sort of self-demonstrate that the design met certification standards.

Friday 22 Feb 2013 Boeing presented an action plan to the FAA:

Boeing remains tight-lipped about its proposed fix, but according to multiple sources, it includes:
• A stronger, sealed containment box enclosing the eight battery cells;
• A system of venting tubes that in case of an incident would channel any flammable vapors or liquids directly out of the airplane;
• Continuous monitoring of temperature and voltage of individual cells within the battery;
• Better thermal separation of the cells, with some barrier such as high-temperature glass inserted between them.


Good luck to Boeing, and hope to see many 787 contrailing the skies soon!



Immigration officer: "What's the purpose of your visit to the USA?" Spotter: "Shooting airliners with my Canon!"
User currently offlinePHX787 From Japan, joined Mar 2012, 7560 posts, RR: 18
Reply 2, posted (1 year 6 months 3 weeks 4 days 4 hours ago) and read 25997 times:

Ok I really would like to follow and contribute to this thread as much as I possibly can. I have a plethora of news that keeps getting posted on Japanese websites, but I find it quite difficult for me to post because of how quickly these threads get out of control. I want to second 777ER's post here, and I would like to add thread 7 and 8 went out of control to become a battle ground as well.

Quoting 777ER (Thread starter):
WARNING: Due to thread 9 going off topic quickly and turning into a 'battle ground', the moderators will be watching this thread frequently and ANY offending/rule breaking posts will be removed. Please respect each others right to have their opinion.

We're 11 threads in with actually little progress into the fix, besides the "temporary" fix that B calls "permanent." Let's focus this time on keeping these things news-oriented. Here's something I see.....

Quoting PW100 (Reply 1):
Basically, the AD says Boeing has to redo this part of the design certification, and demonstrate how they will meet their earlier claims, and more importantly, how they can prove their assumptions. And you can count on it that this time there will be a lot more scrutiny than the first time around, when Boeing had a significant level of “delegated authority” to sort of self-demonstrate that the design met certification standards.

What is Boeing seeing with this fix?
What is this fix-- layman's terms?
How much testing will this require
When will the 787, then, get off the ground again?



次は、渋谷、渋谷。出口は、右側です。電車とホームの間は広く開いておりますので、足元に注意下さい。
User currently offlinegemuser From Australia, joined Nov 2003, 5659 posts, RR: 6
Reply 3, posted (1 year 6 months 3 weeks 4 days 3 hours ago) and read 25871 times:

Quoting PW100 (Reply 1):
Once such an event happened twice in 50,000 hours, or less than two weeks apart, the whole certification basis of the 787 Type Certificate fell away,

This is a gross exaggeration! The "whole basis ... Type Certification" did not fall away. It still stands and is valid. What did happen was the two events in 50,000 hours called in to question compliance with one of the special conditions, which have been discussed to death in these threads. That's why the AD was issued. The problem is NOT a threat to the type certification, just one item, out of thousands.
Of course that one item was enough for the FAA to issue a "before further flight" AD, which is their right & proper role.

Gemuser



DC23468910;B72172273373G73873H74374475275376377L77W;A319 320321332333343;BAe146;C402;DHC6;F27;L188;MD80MD85
User currently offlinesweair From Sweden, joined Nov 2011, 1823 posts, RR: 0
Reply 4, posted (1 year 6 months 3 weeks 4 days 2 hours ago) and read 25737 times:

What did the two events have in common? If we would venture on a guess? Prior to thermal runaway they were running the APU? Was there any drain on the batteries in both events?

User currently offlinejporterfi From United States of America, joined Feb 2012, 444 posts, RR: 0
Reply 5, posted (1 year 6 months 3 weeks 4 days 1 hour ago) and read 25524 times:

Quoting PHX787 (Reply 2):
What is Boeing seeing with this fix?

I may be ridiculed for saying this, but I truly believe that Boeing thinks this fix (coupled with necessary modifications to it that the FAA requires before re-certifying the 787) is permanent. Therefore, I think that Boeing is seeing whether the fix will sufficiently contain any thermal runaway, and prevent is from damaging the aircraft outside of the containment box.

Quoting PHX787 (Reply 2):
What is this fix-- layman's terms?

Essentially it is a stronger containment box made out of steel or titanium, as well as a thicker layer of insulated separator (not sure what material) between the cells. I believe the idea is to keep any thermal runaway from spreading to multiple cells and/or out of the battery.

Quoting PHX787 (Reply 2):
How much testing will this require

Someone on another thread mentioned hte batteries would need to be tested to the point of failure, but I hardly see the point in that much testing. An interesting idea that was previously mentioned is conducting a test flight, then mid-flight, inducing thermal runaway in one cell of a battery and seeing if it spreads to other cells or outside of the containment box (most likely within a certain amount of time).

Quoting PHX787 (Reply 2):
When will the 787, then, get off the ground again?

I think it is far to early to tell. We at least need to wait and see if/when the FAA and NTSB approve Boeing's proposal before more educated speculation can commence.


User currently offlineAeroWesty From United States of America, joined Oct 2004, 20632 posts, RR: 62
Reply 6, posted (1 year 6 months 3 weeks 4 days ago) and read 25453 times:

Quoting jporterfi (Reply 5):
I think it is far to early to tell. We at least need to wait and see if/when the FAA and NTSB approve Boeing's proposal before more educated speculation can commence.

A lot of these questions are answered in the Seattle Times article linked above. In regards to testing and return to service, it notes a couple of interesting things:

Quote:

What’s unclear is how much testing the FAA will require to validate the safety of the revamped battery.

Barnett said the tests conducted on the batteries by Boeing during the original certification process — baking the battery in an oven, puncturing it with a nail, crushing it, and overcharging it — are standard industry tests but don’t reflect what typically happens when a battery fails due to an internal short circuit.

...

And the FAA will want thorough testing of Boeing’s fix, he said.

“The last thing the FAA can stand is to fast-track this and then have something else go wrong,” Hamilton said.

...

A further uncertainty, he said, is that 24 of the 50 Dreamliners that are grounded worldwide are operated by just two Japanese airlines.

Whatever the FAA decides, the Japan Transport Safety Board is expected to be conservative in allowing those jets to fly.



International Homo of Mystery
User currently offlineB777LRF From Luxembourg, joined Nov 2008, 1359 posts, RR: 3
Reply 7, posted (1 year 6 months 3 weeks 3 days 23 hours ago) and read 25302 times:

So what Boeing's essentially proposing is something along the lines of "We don't know what happened to the battery, so we can't stop it from happening again. If it does catch fire, here's a solid box to drop it in, a couple of vent tubes and a few extra lines in the QRH for the boys at the sharp end. Job jobbed, can we go back flying again please"?

The whole idea of "let 'er burn, containment will do" as the sole and final fix is utterly perplexing, runs contrary to everything the safety standards of aviation embrace, and should not be allowed to stand.

If the FAA has just a smidgen of testicular fortitude, they'll tell Boeing to sod off and come back when they've got a battery system to present that's no more liable to combustion than "industry best practice". Whether that can be done with Li-Ion, NiCad's or something else is besides the point. And if the FAA won't do it, one hopes there are other NAA's out there who won't be afraid to say "sorry, not on my watch" and thus scuttle this half-baked, non-conforming, abortion from taking flight.



From receips and radials over straight pipes to big fans - been there, done that, got the hearing defects to prove
User currently offlineXT6Wagon From United States of America, joined Feb 2007, 3409 posts, RR: 4
Reply 8, posted (1 year 6 months 3 weeks 3 days 23 hours ago) and read 25207 times:

Quoting B777LRF (Reply 7):
The whole idea of "let 'er burn, containment will do" as the sole and final fix is utterly perplexing, runs contrary to everything the safety standards of aviation embrace, and should not be allowed to stand.

no it isn't. Lots of things on an airplane are allowed to break. If we use your critera no aircraft would ever fly as engines break more than never. Lets be more blunt. The battery is a back up for *6* units any 2 of which keeps the plane fully powered as far as safety goes. The 4 generators on the engine would all have to offline in one very short event to keep the APU 2 generators from being online. In such a case the batteries would be needed as a bridge between main power system failure and APU start. We are getting into events that are extremely remote, and you can bet that any aircaft with a main battery failure would be diverting as soon as possible regardless of the cause of the failure.

So what Boeing is attempting to do is prove that only the battery would break in the case of thermal run-away. From my perspective they are already most of the way there as the current system clearly worked fine twice. So even better thermal management of the battery in thermal runaway coupled with external venting of the by-products is pretty much golden.


User currently offlineAngMoh From Singapore, joined Nov 2011, 488 posts, RR: 0
Reply 9, posted (1 year 6 months 3 weeks 3 days 22 hours ago) and read 25078 times:

Quoting XT6Wagon (Reply 8):
no it isn't. Lots of things on an airplane are allowed to break.

Yes they are allowed to break, but they are not allowed to go up in flames.

Quoting XT6Wagon (Reply 8):
Lets be more blunt. The battery is a back up for *6* units any 2 of which keeps the plane fully powered as far as safety goes. The 4 generators on the engine would all have to offline in one very short event to keep the APU 2 generators from being online. In such a case the batteries would be needed as a bridge between main power system failure and APU start.

The 787 did not get grounded because the batteries failed. The 787 got grounded because 2 batteries experienced thermal runaway at a rate significantly higher than predicted by the certification process. One resulted in a fire and in the other case the pilot made an emergency landing due to a suspected fire. Had they just failed to work, there would be no fire and no emergency landing and the 787 would not be grounded today.

Quoting XT6Wagon (Reply 8):
So what Boeing is attempting to do is prove that only the battery would break in the case of thermal run-away. From my perspective they are already most of the way there as the current system clearly worked fine twice. So even better thermal management of the battery in thermal runaway coupled with external venting of the by-products is pretty much golden.

Here I disagree strongly and even the FAA disagreed strongly in the Cessna Citation case. First thermal runaway should be extremely rare. Secondly, in the event it happens it should be harmless. And from my perspective, the current system did not work in both events. Boeing is not improving the thermal management as they admit they don't know what caused the thermal runaway. They only try to make the thermal runaway harmless. And here I think Boeing underestimates the degree that other parties will cover their butt. The FAA, being a government organisation, is not going to take any risks because they received enough criticism till now, and airlines are going to play it safe because they can not afford another smoking 787 in the news. Just look at how long it took for the media scrutiny the reduce after the QF32 incident: even today the day to day issues with A380s get blown up (see the Emirates "door blowout" news).


User currently offlineAA737-823 From United States of America, joined Mar 2000, 5814 posts, RR: 11
Reply 10, posted (1 year 6 months 3 weeks 3 days 22 hours ago) and read 25075 times:

Quoting XT6Wagon (Reply 8):
The battery is a back up for *6* units any 2 of which keeps the plane fully powered as far as safety goes.

Any one of those *6* units can be MEL'd; the battery cannot. Further, it is fully required to be in full health for ETOPS operations, so at that point, you've got an ETOPS airplane that can't fly target missions, and realistically can't leave the ground.

Quoting B777LRF (Reply 7):
The whole idea of "let 'er burn, containment will do" as the sole and final fix is utterly perplexing, runs contrary to everything the safety standards of aviation embrace, and should not be allowed to stand.

Agreed; consequently, as we can all agree that it is NOT in Boeing's best interest to pay the costs of lawsuits after a fiery 787 crash, I am hoping like you are that BoCo has another plan.

Quoting B777LRF (Reply 7):
If the FAA has just a smidgen of testicular fortitude, they'll tell Boeing to sod off and come back when they've got a battery system to present that's no more liable to combustion than "industry best practice".

The FAA exerts testicular fortitude when and where they wish. We've seen them over-punish some, while simultaneously under-punishing others. But it may be a moot point; in the linked article above, it's reported that the JTSB has no interest in permitting the airplanes into their airspace until the root cause is known and exhausted.


User currently offlinesankaps From United States of America, joined Jan 2008, 2255 posts, RR: 2
Reply 11, posted (1 year 6 months 3 weeks 3 days 22 hours ago) and read 25048 times:

Quoting XT6Wagon (Reply 8):
. From my perspective they are already most of the way there as the current system clearly worked fine twice.

Unfortunately your perspective is not shared by the airlines involved, the FAA, the NTSB, most external technical experts, or even by Boeing's CEO McNerney. And there have been 10 threads which try to explain why the current system did not "clearly work fine twice". A system that works fine does not result in the scenes we saw with both the JAL and ANA incidents.

In a nutshell Boeing has two things to fix: Significantly reduce the probability of batteries failing in this manner, and improve the containment when the battery does fail. What they have proposed thus far is for the latter; they still do not have a solution for the former, as no one yet knows what caused the batteries to fail.


User currently offlinemjoelnir From Iceland, joined Feb 2013, 1449 posts, RR: 2
Reply 12, posted (1 year 6 months 3 weeks 3 days 22 hours ago) and read 25039 times:

When a robust containment, I am not of the opinion the old one was working, vents directly outside, keeping flame, smoke and explosive gases from entering the e-bay there is one question left, what exactly is the function of the main battery in flight, can the B 787 live without it.

If it is only a backup for electrical generation, than I agree that electrical generation is pretty well covered, having two engines with four generators, apu and rat.

But somewhere in this thread, I am to lazy to find it, it was said that the main battery was a backup for the flight instruments in case of an electrical failure as opposed to a generating failure. That means electrical generation is okay, engines running, generators generating but some electrical fault is scrambling the electrics.


User currently offlineAndyEastMids From United Kingdom, joined Jan 2001, 1017 posts, RR: 2
Reply 13, posted (1 year 6 months 3 weeks 3 days 21 hours ago) and read 24838 times:

“...we won’t allow the 787 to return to commercial service until we’re confident that any proposed solution has addressed the battery failure risks,” said an FAA statement

To me this suggests that the FAA are not requiring Boeing to stop (or reduce the frequency of) batteries failing, but are only expecting Boeing to improve what happens when a battery does fail.


User currently offlineart From United Kingdom, joined Feb 2005, 3382 posts, RR: 1
Reply 14, posted (1 year 6 months 3 weeks 3 days 21 hours ago) and read 24766 times:

Quoting XT6Wagon (Reply 8):
So what Boeing is attempting to do is prove that only the battery would break in the case of thermal run-away. From my perspective they are already most of the way there as the current system clearly worked fine twice.

To me the point is that the frequency of failure appears to be higher than that allowed, even if containment worked perfectly.

Quoting AngMoh (Reply 9):
The 787 did not get grounded because the batteries failed. The 787 got grounded because 2 batteries experienced thermal runaway at a rate significantly higher than predicted by the certification process.

Concur with your statement.

Quoting sankaps (Reply 11):
In a nutshell Boeing has two things to fix: Significantly reduce the probability of batteries failing in this manner, and improve the containment when the battery does fail.

Concur with your statement.

I hope Boeing can come up with an acceptable battery system (probability of failure / containment performance in case of failure) without it taking many months. They have not been lucky with this aircraft (although if you can make your own luck they did a bad job of doing that - premature rollout for silly reasons etc).


User currently offlineasctty From United Kingdom, joined Dec 2008, 117 posts, RR: 0
Reply 15, posted (1 year 6 months 3 weeks 3 days 20 hours ago) and read 24459 times:

The thing for me is what is the purpose of the battery? If it is a safeguard against a failure of the normal electrical supply? What I have yet to see on any of these threads is what was the status of the battery that went on fire? Was is it on load, or was is it on stand-by? If it was on load did the pilots notice any loss of function? If it was on stand-by, lucky the pilots did not have to rely on it.
A containment will not fix the issue regarding the function of the battery. It will only stop the battery becoming another cause for a hazard, i.e. fire!
There are still many unanswered questions about this issue.


User currently offlineRheinbote From Germany, joined May 2006, 1968 posts, RR: 52
Reply 16, posted (1 year 6 months 3 weeks 3 days 20 hours ago) and read 24201 times:

Quoting mjoelnir (Reply 12):
But somewhere in this thread, I am to lazy to find it, it was said that the main battery was a backup for the flight instruments in case of an electrical failure as opposed to a generating failure.

The flight control electronics have their own dedicated back-up battery.


User currently offlineWisdom From , joined Dec 1969, posts, RR:
Reply 17, posted (1 year 6 months 3 weeks 3 days 19 hours ago) and read 23902 times:

Quoting XT6Wagon (Reply 8):
no it isn't. Lots of things on an airplane are allowed to break. If we use your critera no aircraft would ever fly as engines break more than never. Lets be more blunt. The battery is a back up for *6* units any 2 of which keeps the plane fully powered as far as safety goes. The 4 generators on the engine would all have to offline in one very short event to keep the APU 2 generators from being online.

This is not what you have the battery for. Batteries are not meant to be used as a transitionary power source.
When you lose one engine, you still have 2 gens and you start firing up the APU immediately (or the APU fires up automatically). You don't wait until the other engine quits and the probability of losing both engines is low (that's what she said... history says otherwise).


The battery is there to deal with a major electrical failure, such as one that could be caused by major short-circuiting, electrical arching, such as could be caused by a major lightning strike, maintenance error, FOD, etc.
These are situations wherein there is no power flowing from any generators, to the essential systems for flight, no matter whether the generators are or are not producing any power.

May I remind you that Boeing has had one similar incident with the 787 already, with the fire caused by FOD on the P100 panel, resulting in cascading electrical failures, and ended up with battery providing power to the essential busbar for the diversion.

Quoting PW100:
First you write that the battery will have to feed the critical systems for the full duration of the diversion:

Quoting Wisdom (Reply 229):
No that's not what a battery is for. The battery is supposed to hold up critical systems for the duration of the diversion in case of an electrical failure. That is standby instruments, a navigation display and if possible, DC pumps to charge the accumulators (electric braking in the 787's case).

5.5 hours is tight on a 2kwh battery

And then you state that the battery will only need to provide power for 10 seconds:

Quoting Wisdom (Reply 229):
An APU takes 10 seconds to fire-up, if other gens are online you don't need the main battery to power anything at all, I don't see why you would fly with any of the 4 engine gens offline on something as hungry on electricity as the 787. So even if you lose an engine, you'd still have 2 gens providing electricity to the essential busbars as their first priority

BTW How do you envision a 5.5 hr glide . . . ? You mean the aircraft will fly for 5.5 hrs without any electrical power generation?

As long as engines are running, you’re pretty much guaranteed to have at least one generator on-line**. If not, then there is the APU gen that will come on-line within a minute or so. If not, then there is the RAT-gen, which surely will provide more accumulated power than a battery can provide over a 5.5 hour period.

** Not to mention that as soon as one engine fails (or even one generator, I think) the APU will be started, which brings and additional two generators on-line.

Quoting Wisdom (Reply 229):
As to the RAT, if it gets that far, ie no generation at all, a battery is a welcome addition. The RAT will have its hands full providing power to the hydraulics, if it works that is. The RAT is, like the battery, a system of last resort. However, the rat is not something that you use on a daily basis so you don't know if it works until it deploys and starts feeding your systems

The RAT also drives a generator. I would tend to believe that there is a good reason Boeing added the weight of a RAT driven generator . . . And the RAT system is very simple, and thus pretty pretty reliable, I would expect.

So the APU and eventually the RAT will take care of your bad day. The battery will cover the delay in getting one of these on-line. And the battery will stop the aircraft at roll-out once airspeed drops below 60 knots or so - above that speed the RAT-gen still provides sufficient power for the electric brakes.

Quoting Wisdom (Reply 229):
Braking doesn't take as much as one would think, once the brakes are engaged, there is barely any power required unless released and reapplied

I find this interesting. I'm not disputing. It is just that I would expect that a significant force would be required to pull the brake discs together. Doing this electrically will require a significant current draw to generate the required EMF force. I did not expect that engaging the brakes will require more current than keeping them engaged.
I can see that what you are saying would apply to hydraulic actuation, but I did not expect that from electrical actuation. I would appreciate if you could provide more insight.

See above.
Again, you're focusing too much on the engine failure scenario.

The battery is not there for an engine failure scenario that would result in partial loss of electrical generation, they are there as a back-up for a major main electrical system failure.

In an aircraft, wires run in bundles and are situated in places that are inaccessible or impossible to inspect. If such bundles chafe against a sharp edge, it could uncover insulation, start a major short-circuit or paired with moisture and Kapton even start an electrical fire that could cascade into multiple electrical failures, in the worst case scenario even a total loss of the AC electrical systems.

All this while all engines are running, and all gens are online (in reality the gens will automatically go on standby).

In such scenario, the RAT is not really useful and I'm not even sure that it would deploy (depends on individual aircraft type's architecture).

Remember that ETOPS ratings are diversion times at one engine cruise speeds/altitudes. So in most scenario's on conventional airliners where you have an electrical failure but still have engines, you would be less than 5.5 hours away from your diversion airport.

The only tricky thing about the B787 is that it runs the A/C and pressurisation on AC electricals. So as I said in the past weeks, a total AC electrical failure would require the B787 to fly a diversion (with both engines) at a low sustainable breathing altitude for the passengers of around 14000 feet, which will result in lower speed and higher fuel burn.

In light of this, I'm not sure that the one-engine out scenario would result in higher fuel consumption than the AC electricals failure scenario, I hope that Boeing and the FAA took that into consideration during certification.

Even worse would be a single engine failure with a total AC electricals failure.
You would need to fly on one engine at 14.000 feet, I hope that that is a scenario that they have taken into account during certification.

[Edited 2013-02-24 06:14:36]

User currently offlineWisdom From , joined Dec 1969, posts, RR:
Reply 18, posted (1 year 6 months 3 weeks 3 days 19 hours ago) and read 23675 times:

Regarding your question about electric braking:

Looking at the picture of the brake assembly (just google it), it looks to me like it's just the hydraulic pistons which press the rotors and stators together to create the braking effect, that have been replaced by electric actuators. Once the actuators are activated the power to maintain the m actuated should be minimal as most of the load will be absorbed by the threads of the screws of the actuator.

Be reminded that emergency braking usually activates only select brake assemblies, meaning that you don't have full control of braking/steering.

The UA497 is a recent event wherein a A320 lost all AC power due to an electric fire, they returned on the batteries and the RAT.
see http://avherald.com/h?article=43a6bc08

Even though the batteries didn't provide sufficient power for a completely controlled stop, everybody walked away.
Batteries are the electric back-up system of last resort, on which a pilot should be able to rely even on the worst of days.

That's what batteries are for.

[Edited 2013-02-24 06:39:35]

User currently offlineRevelation From United States of America, joined Feb 2005, 12543 posts, RR: 25
Reply 19, posted (1 year 6 months 3 weeks 3 days 18 hours ago) and read 23569 times:

Quoting PW100 (Reply 1):
Continuous monitoring of temperature and voltage of individual cells within the battery

Interesting how the word "monitoring" is used. In the last thread a poster was implying that the BMS could also take an individual cell offline, but I see no evidence of that in the public statements. The existing "special conditions" says the battery charger needs to be able to be disconnected from the battery but nothing about isolating an individual cell as far as I can determine.

Quoting jporterfi (Reply 5):
An interesting idea that was previously mentioned is conducting a test flight, then mid-flight, inducing thermal runaway in one cell of a battery and seeing if it spreads to other cells or outside of the containment box (most likely within a certain amount of time).

They'd never do that in air, they'd do it in an enviornmental simulator.

Quoting AeroWesty (Reply 6):
"The last thing the FAA can stand is to fast-track this and then have something else go wrong," Hamilton said.

That's in essence what I said in the previous thread and got a lot of push-back on it. Actually I said Boeing could not stand such a scenario, but the idea is the same.

Quoting B777LRF (Reply 7):
The whole idea of "let 'er burn, containment will do" as the sole and final fix is utterly perplexing, runs contrary to everything the safety standards of aviation embrace, and should not be allowed to stand.

To be the devil's advocate, and to echo what was said in the last thread, this is how engine blade containment works. The issue we both have is that Boeing is amazingly mute about what they are doing to address the single cell failure issue.

Quoting AngMoh (Reply 9):
Boeing is not improving the thermal management as they admit they don't know what caused the thermal runaway. They only try to make the thermal runaway harmless. And here I think Boeing underestimates the degree that other parties will cover their butt. The FAA, being a government organisation, is not going to take any risks because they received enough criticism till now, and airlines are going to play it safe because they can not afford another smoking 787 in the news.

I think I see FAA manuevering for a climb-down. I don't know to what degree the other players are going to go along.

Quoting AA737-823 (Reply 10):

The FAA exerts testicular fortitude when and where they wish. We've seen them over-punish some, while simultaneously under-punishing others. But it may be a moot point; in the linked article above, it's reported that the JTSB has no interest in permitting the airplanes into their airspace until the root cause is known and exhausted.

Yes, that could be how it plays out. It seems JTSB were the ones who visited the firm that manufactures the cells. Perhaps they are the ones taking the lead on investigating the single cell failures?

Quoting sankaps (Reply 11):
In a nutshell Boeing has two things to fix: Significantly reduce the probability of batteries failing in this manner, and improve the containment when the battery does fail. What they have proposed thus far is for the latter; they still do not have a solution for the former, as no one yet knows what caused the batteries to fail.

We are being told that the root cause for these instances of cell failure might never be known because the evidence has been consumed by fire. I imagine there's a list of suspected root causes and relative probabilities based on the evidence, but it's hard to force an action based on this, IMHO. Still, I'm quite concerned that we aren't being told what is going to be done to address the more probable root causes.

Quoting AndyEastMids (Reply 13):
“...we won’t allow the 787 to return to commercial service until we’re confident that any proposed solution has addressed the battery failure risks,” said an FAA statement

To me this suggests that the FAA are not requiring Boeing to stop (or reduce the frequency of) batteries failing, but are only expecting Boeing to improve what happens when a battery does fail.

Yes, this is a big part of why I think I see FAA manuevering for a climb-down. It's hard to reconcile 10,000% safe with that statement, though.



Inspiration, move me brightly!
User currently offlinesankaps From United States of America, joined Jan 2008, 2255 posts, RR: 2
Reply 20, posted (1 year 6 months 3 weeks 3 days 18 hours ago) and read 23514 times:

Quoting Revelation (Reply 19):
To be the devil's advocate, and to echo what was said in the last thread, this is how engine blade containment works.

Revelation, that is true. However I am sure there are, in parallel, certain agreed to numbers for what acceptable engine blade failure rates are; if it were happening at what is feared to be 20x the expected rate and containment too was not working exactly as hoped, then it is highly likely the said engines would be grounded too.


User currently offlinePugman211 From UK - England, joined Dec 2012, 107 posts, RR: 0
Reply 21, posted (1 year 6 months 3 weeks 3 days 18 hours ago) and read 23403 times:

Quoting Wisdom (Reply 18):
Even though the batteries didn't provide sufficient power for a completely controlled stop, everybody walked away.
Batteries are the electric back-up system of last resort, on which a pilot should be able to rely even on the worst of days.

That's what batteries are for.

So long as your battery isn't on fire or bricked....


User currently offlinecornutt From United States of America, joined Jan 2013, 338 posts, RR: 1
Reply 22, posted (1 year 6 months 3 weeks 3 days 18 hours ago) and read 23318 times:

Quoting B777LRF (Reply 7):
The whole idea of "let 'er burn, containment will do" as the sole and final fix is utterly perplexing, runs contrary to everything the safety standards of aviation embrace, and should not be allowed to stand.

But as I pointed out in the last thread, that's precisely how we handle blade failures in engines. It is not required to design an engine such that it is guaranteed to never throw a blade, nor does anyone know how to do so. We design containment into the engines.

Quoting Wisdom (Reply 17):
The battery is there to deal with a major electrical failure, such as one that could be caused by major short-circuiting, electrical arching, such as could be caused by a major lightning strike, maintenance error, FOD, etc.
These are situations wherein there is no power flowing from any generators, to the essential systems for flight, no matter whether the generators are or are not producing any power.

You're making assumptions about the architecture of the electrical system that are probably not true. First of all, if an essential bus is shorted, then it will still be shorted when the battery is placed on it. So that's no help. Second, there have to be at least two busses, or sets of busses, that are separate up to and including physically separated routing through the aircraft. You can't ever have a situation, battery or no battery, where a fire in one electrical tray takes out all of the electrical systems. I'm pretty sure that what you said about the ZA002 incident is not true; if memory serves they were able to start the APU and it provided power for the diversion. I think there are either three or four main busses. The captain and F/O instruments can probably be switched to at least two essential busses, and each essential bus can probably be switched to at least two different main busses. If what I've read is correct, the main battery is hard-tied to a single main bus. Lose that bus, you've lost the battery.

And as has been pointed out, the battery simply does not have enough capacity to power the aircraft in flight for five-and-a-half hours. Likely it does not enter into the ETOPS calculation at all.


User currently offlinea3xx900 From Germany, joined Jan 2004, 335 posts, RR: 0
Reply 23, posted (1 year 6 months 3 weeks 3 days 18 hours ago) and read 23236 times:

I don't know if this has been asked before and excuse me for not searching 11 topics and hundreds of replies for this, but:

Why can't airlines even reposition their aircraft (non-rev) to their home airports? E.g. the ANA 787 sitting in FRA and the JAL sitting in BOS?



Why is 10 afraid of 7? Because 7 8 9.
User currently offlineStitch From United States of America, joined Jul 2005, 30978 posts, RR: 86
Reply 24, posted (1 year 6 months 3 weeks 3 days 18 hours ago) and read 23217 times:
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Quoting a3xx900 (Reply 23):
Why can't airlines even reposition their aircraft (non-rev) to their home airports?

They can with the proper waivers. Evidently they are content to leave the planes where they are for whatever reason(s).


User currently offlinecornutt From United States of America, joined Jan 2013, 338 posts, RR: 1
Reply 25, posted (1 year 6 months 3 weeks 3 days 18 hours ago) and read 23591 times:

Quoting a3xx900 (Reply 23):
Why can't airlines even reposition their aircraft (non-rev) to their home airports? E.g. the ANA 787 sitting in FRA and the JAL sitting in BOS?

They can, if they do the work to plan a ferry flight with the proper restrictions. In fact, I think that one or two of them have been moved. But right now there's really no motivation, since the airlines don't know what they are going to have to do or where the aircraft will need to be taken. (There's still the possibility, although it looks unlikely now, that they will all have to be flown back to Everett to be modified.) The airlines probably figure that for the time being, as long as the planes are in a place where they are secure and properly "winterized", there's no point in expending the fuel and crew hours to move them.


User currently offlinepar13del From Bahamas, joined Dec 2005, 7202 posts, RR: 8
Reply 26, posted (1 year 6 months 3 weeks 3 days 17 hours ago) and read 23468 times:

Quoting Wisdom (Reply 17):
May I remind you that Boeing has had one similar incident with the 787 already, with the fire caused by FOD on the P100 panel, resulting in cascading electrical failures, and ended up with battery providing power to the essential busbar for the diversion.

It should also be mentioned that while on approach most essential systems were coming back online I believe independent of the battery, the experts can confirm, so that incident also showed the redundancies built into the system and that they did function as expected.


User currently offlineRayChuang From United States of America, joined Jun 2000, 8017 posts, RR: 5
Reply 27, posted (1 year 6 months 3 weeks 3 days 16 hours ago) and read 23403 times:

My guess is that Boeing should have a "safer" battery ready by late this summer, and eventually the 787 will go away from the current Li-On battery design to a new, far safer dry-electrode Li-On battery within the next few years.

User currently offlinesweair From Sweden, joined Nov 2011, 1823 posts, RR: 0
Reply 28, posted (1 year 6 months 3 weeks 3 days 16 hours ago) and read 23359 times:

Too bad no fuel cell options are in the market, as Airbus told, it filled the cargo hold on their A320.. Isn´t there a market to design and build JetA fueled fuel cells for airliners? But what do you do with the waste heat?

User currently offlineRheinbote From Germany, joined May 2006, 1968 posts, RR: 52
Reply 29, posted (1 year 6 months 3 weeks 3 days 16 hours ago) and read 23185 times:

Quoting sweair (Reply 28):
Too bad no fuel cell options are in the market, as Airbus told, it filled the cargo hold on their A320.. Isn´t there a market to design and build JetA fueled fuel cells for airliners?

That kind of flying refinery would probably be even harder to certify than Lithium-Ion batteries.


User currently offlinekanban From United States of America, joined Jan 2008, 3547 posts, RR: 26
Reply 30, posted (1 year 6 months 3 weeks 3 days 15 hours ago) and read 22964 times:
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So as we go into part 11, everybody from the airlines to the FAA, NSTB to Boeing are posturing through releases (leaked or otherwise) and many posters are trying to interpret the posturing. Bottom line, we don't know which line is the actual and which is posturing. Sometimes an agency will release a position the day before a congressional hearing just to defuse the hearing. So while they may not be lying, they may not be telling the whole story or using words in a different context than normal.

Personally I think the FAA will accept the Boeing plan with a token revision that shows they're in charge. Then Boeing will pursue revising the battery/battery chemistry/battery system with various manufacturers. The reason for the proposal to be labeled the ultimate fix may be that Yuasa can not adequately improve the cell chemistry or eliminate all contamination. New supplier's batteries may require more substantive electrical bay revisions and certification so developing them will take longer.

I believe that the Japanese are looking at the APU battery from that ANA plane where one cell showed deformation but no thermal run away.. there may be an answer coming there

As far as ETOPS/ battery functions, EE bay relationships, and fire propagation and extinguishing; please read the posts of Tdscanuck, CM, and Rcair1 .. they have stated plainly what is involved. We've had other vehement posters with do or die positions based on hearsay, opinion and fear.. While in a open forum all opinions are welcome, let's try to base them on fact.


User currently offline7BOEING7 From United States of America, joined Oct 2012, 1591 posts, RR: 8
Reply 31, posted (1 year 6 months 3 weeks 3 days 15 hours ago) and read 22843 times:

Quoting Wisdom (Reply 17):
The only tricky thing about the B787 is that it runs the A/C and pressurisation on AC electricals. So as I said in the past weeks, a total AC electrical failure would require the B787 to fly a diversion (with both engines) at a low sustainable breathing altitude for the passengers of around 14000 feet, which will result in lower speed and higher fuel burn.

In light of this, I'm not sure that the one-engine out scenario would result in higher fuel consumption than the AC electricals failure scenario, I hope that Boeing and the FAA took that into consideration during certification.

During the 777-300ER certification Boeing did at least one flight with a simulated decompression (flight at 10,000ft) and one engine out for 5 hours or more so I'm sure it was considered if not flown during 787 certification.And I believe in service an ETOPS flight takes simiar issues into consideration.

In the 787 as well as other modern airliners the battery doesn't last forever--30 minutes maybe a little more--it is not expected to power the essential instruments for a 5.5 hour divert.


User currently offlineStitch From United States of America, joined Jul 2005, 30978 posts, RR: 86
Reply 32, posted (1 year 6 months 3 weeks 3 days 15 hours ago) and read 22895 times:
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Been reviewing the PPRune.net threads on this issue and found the following:

In regards to JA804A, NHK News is reporting that the JTSB has determined that the wiring for the APU battery had been installed correctly per the design blueprints. However, electricity continued to flow from the APU battery into the bus that powers the plane's navigation lights even though the flight crew had turned the relevant switches off on the flight deck.

The JTSB has found that the ground wires in the Ship's Battery were fused by an internal short circuit. They also report that the Ship's and APU batteries had been erroneously wired together (this part has me confused - they're supposed to be electrically connected since they work concurrently to start the APU).

The original battery design had only a single temperature sensor. The BMS managed the charging of cells using software that predicted the temperatures from the voltage across the cells. Hence reports Boeing will now install a temperature sensor for each cell going forward.


User currently offlinenycdave From United States of America, joined Aug 2010, 547 posts, RR: 1
Reply 33, posted (1 year 6 months 3 weeks 3 days 15 hours ago) and read 22688 times:

Quoting jporterfi (Reply 5):
Someone on another thread mentioned hte batteries would need to be tested to the point of failure, but I hardly see the point in that much testing. An interesting idea that was previously mentioned is conducting a test flight, then mid-flight, inducing thermal runaway in one cell of a battery and seeing if it spreads to other cells or outside of the containment box (most likely within a certain amount of time).

Why would they even need to do this in a test flight? If you're testing the containment between cells, and within the unit as a whole, seems like you could do that on the ground just as well, maybe just adjusting atmosphere or airflow in the testing chamber if you want to see what happens with venting?

Anyhow, according to the NYT today, sounds like Boeing has a fix in the works that would protect against all the theorized causes of failure causing destruction of the whole battery... Would love to hear some of the folks on here comment (if any of it is even slightly new news...)


User currently offlinejustloveplanes From United States of America, joined Jul 2004, 1056 posts, RR: 1
Reply 34, posted (1 year 6 months 3 weeks 3 days 15 hours ago) and read 22502 times:

Quoting AngMoh (Reply 9):
Yes they are allowed to break, but they are not allowed to go up in flames.

Containment properly done make this issue a non-event from a thermal safety perspective. As has been stated previously, the total amount of energy releasable in a thermal event from the LiIon battery is known. It can be designed for, and was, but a bit too marginally. The issue is increased containment adds weight, which is why this too light containment strategy was implemented IMHO, to save weight. I would bet the engineers at Boeing considered heavier containment (as Airbus did even before these incidents according to posts on this thread), they are smart folks. The Boeing engineers made the wrong choice, but fixing it isn't an side of body join type of problem. Up the containment, take the weight penalty, on you go.

Quoting AngMoh (Reply 9):
Secondly, in the event it happens it should be harmless.

Easily acheivable as stated above. Take the hit on the weight. I"ll bet Boeing's solution is less than 100 lbs additional.

Quoting AngMoh (Reply 9):
Boeing is not improving the thermal management as they admit they don't know what caused the thermal runaway.

Yes is does, Boeing is designing for a worse thermal case incident on a frequent/continuous basis - assume a runaway every flight and design the system accordingly. An approach like this removes thermal management as a safety issue.

What is left is system availability to address. How is safety affected from a system operations (not thermal hazard) point of view when *both* batteries (main and APU) fail? I am assuming the batteries can cross feed one another's duty loads as stated elsewhere on these threads.

I don't think Boeing's cell isolation solution helps this. Apparently one cell failure may not cause thermal runaway of the pack, but the voltage in series design incapacitates the operational function of a pack with even a single isolated cell failure.

So the new math is what is the probability of both packs (main and APU) failing? If these probabilities go back down to very small numbers within certification targets for system availability for ETOPS, then I see no reason why the plane can't go back up.

If the numbers do work for this scenario, then Boeing would be correct in their assertion that the containment measures do indeed create a permanent fix by previously approved metrics. This would not be a subjective call at this point, if the FAA agrees the thermals hazard has been addressed, and system availability probabilities are within range, the plane should go back up.

[Edited 2013-02-24 11:09:46]

[Edited 2013-02-24 11:13:13]

User currently offlineblrsea From India, joined May 2005, 1423 posts, RR: 3
Reply 35, posted (1 year 6 months 3 weeks 3 days 14 hours ago) and read 22462 times:

I have a question regarding the new containment and venting design that Boeing has proposed. Will they actually let a battery catch fire and verify that it works properly in such a situation? Or do they simulate a fire inside the box using other materials and verify that containment & venting of smoke to outside works?

User currently offlinesweair From Sweden, joined Nov 2011, 1823 posts, RR: 0
Reply 36, posted (1 year 6 months 3 weeks 3 days 14 hours ago) and read 22329 times:

Quoting blrsea (Reply 36):

I they can simulate a nuclear blast they surely can simulate a lithium fire. Germany and later China did test to shut down cooling on the HTR reactor, having simulated this earlier and the results were very similar in the real event.

If you know the input energy you know the possible output energy.


User currently offlinemjoelnir From Iceland, joined Feb 2013, 1449 posts, RR: 2
Reply 37, posted (1 year 6 months 3 weeks 3 days 14 hours ago) and read 22318 times:

Quoting justloveplanes (Reply 35):
What is left is system availability to address. How is safety affected from a system operations (not thermal hazard) point of view when *both* batteries (main and APU) fail? I am assuming the batteries can cross feed one another's duty loads as stated elsewhere on these threads.

I don't think Boeing's cell isolation solution helps this. Apparently one cell failure may not cause thermal runaway of the pack, but if the voltage in series design incapacitates the operational function of a pack with even a single isolated failure.

So the new math is what is the probability of both packs (main and APU) failing? If these probabilities go back down to very small numbers within certification targets for system availability for ETOPS, then I see no reason why the plane can't go back up.

If the numbers do work for this scenario, then Boeing would be correct in their assertion that the containment measures do indeed create a permanent fix by previously approved metrics. This would not be a subjective call at this point, if the FAA agrees the thermals hazard has been addressed, and system availability probabilities are within range, the plane should go back up.


Here is were Boeing should look at the possibility of subdividing the batteries.
Taken two half sized gives the same KW/h at about the same weight but when one cell goes up you only loose half of the capacity instead of all.

We also have to thing about the possibility that the B 787 will not get its ETOPS 330 straight away. Even ETOPS 180 could be a stretch. In this case the opinion of the FAA is not the only threshold, but as most of the B787 will not be registered in USA, they have to convince all the other regulators.


User currently offlinebellancacf From United States of America, joined May 2011, 152 posts, RR: 0
Reply 38, posted (1 year 6 months 3 weeks 3 days 14 hours ago) and read 22081 times:

A quick look around the Web hasn't turned up any information on the kind of batteries that Boeing was proposing having in the SUGAR Volt aircraft, that "Prius of the Skies", as the media liked to call it, but I would imagine that Li-xx batteries were the leading candidates. What effect is the present situation having on the SUGAR Volt inside Boeing, or inside any other company that was considering a battery-rich aircraft? Perception problems or not, the thermal runaway issue seems to be very real indeed. Was the SUGAR Volt group sort of putting that issue aside until later, or did they -- like Tesla -- take a strongly proactive and preventive line in their design from early on?

User currently offlinesankaps From United States of America, joined Jan 2008, 2255 posts, RR: 2
Reply 39, posted (1 year 6 months 3 weeks 3 days 13 hours ago) and read 21831 times:

Quoting cornutt (Reply 22):
But as I pointed out in the last thread, that's precisely how we handle blade failures in engines. It is not required to design an engine such that it is guaranteed to never throw a blade, nor does anyone know how to do so. We design containment into the engines.

I think my earlier comment addressing this line of reasoning was lost in the discussion above:

I am sure there are, in parallel, certain agreed to numbers for what acceptable engine blade failure rates are; if it were happening at what is feared to be 20x the expected rate (ie 2 instances in 50,000 hours instead of 1 in a million hours), and containment too was not working exactly as hoped, then it is highly likely the said engines would be grounded too.


User currently offlinepacksonflight From Iceland, joined Jan 2010, 381 posts, RR: 0
Reply 40, posted (1 year 6 months 3 weeks 3 days 13 hours ago) and read 21786 times:

Quoting Revelation (Reply 19):
Yes, this is a big part of why I think I see FAA manuevering for a climb-down. It's hard to reconcile 10,000% safe with that statement, though.

The FAA will have to settle for less than 100% security, they are supposed to, but I cannot see FAA climb down from the special requirements set for the Li batteries on the 787, If they do that they have not much credibility left.


User currently offlinejustloveplanes From United States of America, joined Jul 2004, 1056 posts, RR: 1
Reply 41, posted (1 year 6 months 3 weeks 3 days 12 hours ago) and read 21334 times:

Quoting packsonflight (Reply 41):
The FAA will have to settle for less than 100% security, they are supposed to, but I cannot see FAA climb down from the special requirements set for the Li batteries on the 787, If they do that they have not much credibility left.

This would depend on the intent of the special requirement. The assumption for this requirement was a design to provide adequate safety margin for failure every 1,000,000 hours I believe.

If the main concern of the failure for this special condition was a thermal hazard, then the FAA has an option to look at this from another angle. i.e. if (sorry for going on like a broken record, but I think this is key) containment is designed for * routine * failure of a battery from a thermal hazard perspective, the special condition is removed. It is assumed the system doesn't fail every 1,000,000 hours, it assumes regular failures and design for this condition. Regular faults, like a circuit breaker in a home are normal conditions, not special ones.

They system availability issue would then become the main issue to address. I am not sure if it is system availability or hazards of thermal risk that are the FAA's main concern when they say the route cause of the fires must be addressed. The system availability issue is much more vexing. New chemistry, cell architecture, additional redundancy or some combination of these is needed if the availability issue turns out to be the show stopper.


User currently offlineRheinbote From Germany, joined May 2006, 1968 posts, RR: 52
Reply 42, posted (1 year 6 months 3 weeks 3 days 11 hours ago) and read 20850 times:

Quoting bellancacf (Reply 39):
A quick look around the Web hasn't turned up any information on the kind of batteries that Boeing was proposing having in the SUGAR Volt aircraft

A SUGAR Volt concept is like 30 years away at best. You would have to improve energy density by a factor of 100 over Lithium-Ion battery technology to make full-electric large commercial aircraft feasible.


User currently offlinepacksonflight From Iceland, joined Jan 2010, 381 posts, RR: 0
Reply 43, posted (1 year 6 months 3 weeks 3 days 10 hours ago) and read 20278 times:

Quoting justloveplanes (Reply 42):
This would depend on the intent of the special requirement. The assumption for this requirement was a design to provide adequate safety margin for failure every 1,000,000 hours I believe.

For starters the assumed failure rate was 1:10,000,000 operating hours.

I guess that the regulator wanted firstly: to assure that with Li battery system would not be less reliable than conventional system which has well documented track record.

Secondly they wanted to assure that potential on board battery fire did not pose a risk to the aircraft after the test facility for the 787 battery burned down.

System reliability is a big issue on an aircraft specially if you want to have over 300 minutes ETOPS, and it is perfectly normal for the regulator to demand from Li battery system at least equal reliability level as conventional battery system.


User currently offlineAllegiantFlyer From United States of America, joined Mar 2012, 177 posts, RR: 0
Reply 44, posted (1 year 6 months 3 weeks 3 days 8 hours ago) and read 19746 times:

How much money are companies loosing from this grounding?seems to be taking a long period of time.

User currently offlinercair1 From United States of America, joined Oct 2009, 1320 posts, RR: 52
Reply 45, posted (1 year 6 months 3 weeks 3 days 8 hours ago) and read 19610 times:
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Quoting mjoelnir (Reply 47):
You rcair1 objects to what wisdom is saying, but in reality you say the same thing: you need the battery as a safety while flying.

Please do not equate what I say with what Wisdom is saying. With all due respect, we do not agree. I would expect that Wisdom feels the same way.

By way of example - from the previous thread.
-----
Quoting Wisdom (Reply 229):
No that's not what a battery is for. The battery is supposed to hold up critical systems for the duration of the diversion in case of an electrical failure. That is standby instruments, a navigation display and if possible, DC pumps to charge the accumulators (electric braking in the 787's case).
-----
I have not said that the battery is supposed to 'hold up' (power) critical systems for the duration of a diversion.

Quoting mjoelnir (Reply 47):
It does not matter what is completely right in this case, both of you say the battery is needed in flight!!!

I'm sorry - I disagree. It does matter who is "right" when you are talking about engineering.

We agree that the main battery (not APU battery) is a required flight item - which means if you loose it you land - just like if you lose an engine - or many other systems. You cannot take off with a failed battery. Neither can you with lots of systems on the plane.

....???



rcair1
User currently offline7BOEING7 From United States of America, joined Oct 2012, 1591 posts, RR: 8
Reply 46, posted (1 year 6 months 3 weeks 3 days 8 hours ago) and read 19561 times:

Quoting rcair1 (Reply 48):

I agree totally. Wisdom is completely distorting the actual use of the Main battery in a modern airliner


User currently offlinebellancacf From United States of America, joined May 2011, 152 posts, RR: 0
Reply 47, posted (1 year 6 months 3 weeks 3 days 7 hours ago) and read 19465 times:

to Rheinbote @ 43:

100-fold! That IS some speculation, then. I wonder what they had in mind. Presumably something, or the whole thing seems like a pipedream. On the other hand, when our own lipid deposits ("fat") are converted through mitochondria, etc., I've heard that they actually do have an energy density that is about 2 orders magnitude above NiCad technology. But at any rate, nothing in the SUGAR Volt project would have been able to advise the 787 designers on the best way to deal with larger-than-usual, higher capacity batteries subject to thermal runaway. Oh well.


User currently offlinemjoelnir From Iceland, joined Feb 2013, 1449 posts, RR: 2
Reply 48, posted (1 year 6 months 3 weeks 3 days 7 hours ago) and read 19347 times:

Quoting rcair1 (Reply 48):

So to talk facts.

You say there is NO WAY that the ac part of the electrical system goes down and does not come up and the batteries have to keep carrying the load of the flight instruments?
That means you have to be 100% sure for your statements.

How many sets of AC/DC rectifiers are there between the AC/DC systems, and there is no possibility that something punches all of them out, no way?


I know there is redundancy I do not talk about that.


User currently offlineDTW2HYD From United States of America, joined Jan 2013, 1948 posts, RR: 0
Reply 49, posted (1 year 6 months 3 weeks 3 days 7 hours ago) and read 19363 times:

Quoting bellancacf (Reply 50):
But at any rate, nothing in the SUGAR Volt project would have been able to advise the 787 designers on the best way to deal with larger-than-usual, higher capacity batteries subject to thermal runaway.

Boeing is already on record saying they studied every Li-on battery including the ones used in consumer electronics.

Tesla has a white paper on their battery system. It clearly states having large number(6800) of smaller cells creates large surface area to dissipate heat, hence avoid thermal runaway condition. I am not an expert but sounds like a good design idea in the absence of an active cooling system. General Motors has a battery lab continuously testing and improving their VOLT's battery technology. Their battery has 288 cells and a unique aluminum cooling fin design. Both Tesla and GM spent years designing and testing their battery systems. 787 batteries are relatively smaller than these batteries. Chances of car battery getting ruptured is very high than an aircraft. On same note car passengers have higher chance of existing the vehicle after an accident.


User currently offlinemjoelnir From Iceland, joined Feb 2013, 1449 posts, RR: 2
Reply 50, posted (1 year 6 months 3 weeks 3 days 7 hours ago) and read 19186 times:

Quoting rcair1 (Reply 45):
his is one thing it does- and it does it while the system reconfigures to deal with the issue. There is a ton of redundancy in the entire electrical system - loss of one buss, circuit, panel is NOT going to destroy the integrity of the system.

That I believe

Quoting rcair1 (Reply 45):
If it did - the battery - which is part of that system - would be rendered non-functional as well.

That I do not believe.
The system is resetting while the batteries are running the flight instruments.

Why would you design that system so that when you lose it completely the flight instruments would stop running as per your explanation.


User currently offlinealfablue From Spain, joined Jan 2013, 43 posts, RR: 10
Reply 51, posted (1 year 6 months 3 weeks 3 days 7 hours ago) and read 19227 times:

Quoting rcair1 (Reply 48):
I'm sorry - I disagree. It does matter who is "right" when you are talking about engineering.

I don't think it's an engineering problem anymore to be honest -- the dimensions of this grounding are huge. It's a huge PR disaster already independent of the final fix. I don't know and can not know which fraction will win in the sense of: will this be a grounding where we might see the A350 taking to the skies before the Dreamliner goes back on revenue service - or will she fly again in a few weeks?

wisdom has a few valid concerns and so do you rcair - just from different views. Where wisdom was right is that ETOPS and LROPS concerning elec architecture is essentially the same if you look at back up systems. Fuel driven systems need to be seen as one complex as fuel starvation leads all generators and APU useless. So we have RAT and battery. So the battery is actually the third redundancy (like hydraulics) -- look at the Gimli glider and Air Transat incidents.

That is taken into account in the regulations and there wisdom was wrong. Regulations state that on an ETOPS/LROPS flight the battery must assure a safe descent and emergency landing (which lasts roughly 30 minutes and could be a watering -- it does not say diversion in the regulations concerning battery duration versus fire depression for example. The regulators are very specific about those time limites systems.

Another question is therefore. By regulations the main battery stays in a constant state of being charged during the flight. Now you suddenly rely on a very conservative new control mechanism to prevent runaway but in the worst case you go from constant charge to sudden discharge -- can I override a battery shut off logic as a pilot in a worst case scenario?

IMO I dont see the bird flying anytime soon again - sorry - from a pilot and non-engineering perspective.

alfaBlue

[Edited 2013-02-24 18:50:38]

User currently offlineXT6Wagon From United States of America, joined Feb 2007, 3409 posts, RR: 4
Reply 52, posted (1 year 6 months 3 weeks 3 days 6 hours ago) and read 19181 times:

Quoting alfablue (Reply 54):
can I override a battery shut off logic as a pilot in a worst case scenario?

no you can't as the shutoff is at a point in time where the battery is no longer able to safely provide power. So if you are using the battery long enough to hit the shutoff in flight... well the tiny bit of extra power you get between shutoff and battery going offline because of over-discharge isn't going to save you.


User currently offlinealfablue From Spain, joined Jan 2013, 43 posts, RR: 10
Reply 53, posted (1 year 6 months 3 weeks 3 days 6 hours ago) and read 19063 times:

Quoting XT6Wagon (Reply 55):
no you can't as the shutoff is at a point in time where the battery is no longer able to safely provide power

Sorry I should have been more specific -- I didn't mean a shut off at a low state of charge. I was more thinking of an automatic software shut off due to a high temperature sensor reading in the battery for example.

I was posting some disturbing statistics towards the end of threat 10 on this subject and never got an answer. Is there a mathematician who can calculate the chances for the Gimli-glider and Air Transat incidents being Airlines from the same country or even more interesting -- What are the statistic probabilities of Air France crashing all Toulouse produced fly by wire aircraft for the first time with Pax on-board. I always wondered that. Anyone who can do the math as estimation in relation to world wide traffic, number of airlines, countries?

alfaBlue


User currently offlinerwessel From United States of America, joined Jan 2007, 2351 posts, RR: 2
Reply 54, posted (1 year 6 months 3 weeks 3 days 3 hours ago) and read 18548 times:
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Quoting mjoelnir (Reply 47):
Quote from Wisdom
The battery is there to deal with a major electrical failure, such as one that could be caused by major short-circuiting, electrical arching, such as could be caused by a major lightning strike, maintenance error, FOD, etc

Quote from rcair1
It is important? Of course, that is why you cannot fly without it

You rcair1 objects to what wisdom is saying, but in reality you say the same thing: you need the battery as a safety while flying.

rcair1 talks that you need the battery while the system is resetting,
Wisdom says you need the battery for a major electrical failure.

It does not matter what is completely right in this case, both of you say the battery is needed in flight!!!

So as a consequence, the FAA will want a reduced failure rate compared to what has happened, even if the containment is acceptable.

That's not exactly true. There's some level of reliability the electrical system has to achieve, I'm assuming it's the one-terminal-failure-in-a-billion flight hours requirement. So long as the odds of an electrical system failure needing battery backup to get through, combined with the odds of having a main battery fail on the same flight, is below that threshold, there shouldn't be an issue on that basis. Obviously you couldn't dispatch with a dead main battery, since you've immediately blown your reliability requirement (since the odds of a terminal failure are now only the odds of the major electrical malfunction needing battery backup).

This is no different than requiring the odds of both engines failing (on a twin) to be below some threshold. The failure of either engine failing is *much* higher than that threshold, but it's the combined probability that matters.

But we don't actually know what the various stats are going into this, so we have no idea what failure probability Boeing needs to achieve on the main battery to meet the certification requirements, but it's certainly not zero (and no battery every built has a zero failure rate). So the FAA may need some improvement in failure rate to meet the electrical system reliability requirements, or it may not. Again, we don't know.

OTOH, the FAA clearly wants the number of fires (and I'm using the term loosely enough to encompass the events in question) in the battery packs reduced, or perhaps contained in such a way as to minimize the risk to the aircraft. The odds of a battery fire dooming the aircraft needs to meet its own one-in-a-billion-flight-hours threshold, but that threshold is basically unrelated to the reliability of the electrical system.


User currently offlinemjoelnir From Iceland, joined Feb 2013, 1449 posts, RR: 2
Reply 55, posted (1 year 6 months 3 weeks 2 days 21 hours ago) and read 17954 times:

Quoting rwessel (Reply 54):

So not to talk around the bush, the failure rate, 2 in 50.000 hours, exhibited by those batteries is low enough regarding the electrical safety part?
That is would your not exactly true implies.


User currently offlineRevelation From United States of America, joined Feb 2005, 12543 posts, RR: 25
Reply 56, posted (1 year 6 months 3 weeks 2 days 20 hours ago) and read 17730 times:

Quoting justloveplanes (Reply 35):
Boeing is designing for a worse thermal case incident on a frequent/continuous basis - assume a runaway every flight and design the system accordingly. An approach like this removes thermal management as a safety issue.

It seems one then have a perfect containment system, or one that's "not remotely likely" to fail, i.e. once in 10e6 flight hours. Should be interesting certifying that. I know you are saying that this type of design/analysis is routine, but still it should be interesting.

Quoting mjoelnir (Reply 55):
So not to talk around the bush, the failure rate, 2 in 50.000 hours, exhibited by those batteries is low enough regarding the electrical safety part?
That is would your not exactly true implies.

What the FAA said was:

Quote:

Before further flight, operators of U.S.-registered, Boeing 787 aircraft must demonstrate to the Federal Aviation Administration (FAA) that the batteries are safe.

The FAA will work with the manufacturer and carriers to develop a corrective action plan to allow the U.S. 787 fleet to resume operations as quickly and safely as possible.

To not talk around the bush, they didn't say the two data points meant that the plane was unsafe, they said it created the need to demonstrate that they are as safe as possible.



Inspiration, move me brightly!
User currently offlinemoo From Falkland Islands, joined May 2007, 3948 posts, RR: 4
Reply 57, posted (1 year 6 months 3 weeks 2 days 20 hours ago) and read 17691 times:

Quoting Revelation (Reply 56):
To not talk around the bush, they didn't say the two data points meant that the plane was unsafe, they said it created the need to demonstrate that they are as safe as possible.

The FAA cannot say that the two data points mean the plane was unsafe - its entirely possible that Boeing could prove that the the two failures fall outside the bounds of a statistically significant event.

Sure, the FAA may have mandated "one failure every 1 million flight hours", but that doesn't mean you cannot have two failures during any one period - it just means you cannot have more than X number failures in Y period.


User currently offlinesankaps From United States of America, joined Jan 2008, 2255 posts, RR: 2
Reply 58, posted (1 year 6 months 3 weeks 2 days 20 hours ago) and read 17606 times:

Quoting moo (Reply 57):
Sure, the FAA may have mandated "one failure every 1 million flight hours", but that doesn't mean you cannot have two failures during any one period - it just means you cannot have more than X number failures in Y period.

True, but the failures do raise the question of whether it is a statistical anamoly, or whether there is an underlyin problem. Which is why this remark below

Quoting Revelation (Reply 56):
To not talk around the bush, they didn't say the two data points meant that the plane was unsafe, they said it created the need to demonstrate that they are as safe as possible.

makes complete sense. And is also the view taken by Boeing CEO McNerney when the engineers were trying to use similar logic to explain the issue.


User currently offlinemoo From Falkland Islands, joined May 2007, 3948 posts, RR: 4
Reply 59, posted (1 year 6 months 3 weeks 2 days 20 hours ago) and read 17555 times:

Quoting sankaps (Reply 58):
True, but the failures do raise the question of whether it is a statistical anamoly, or whether there is an underlyin problem.

Yup, I was just highlighting that there was a possible avenue where Boeing could end up doing nothing at all.

A highly unlikely course of action, but a possible one none the less.


User currently offlineWisdom From , joined Dec 1969, posts, RR:
Reply 60, posted (1 year 6 months 3 weeks 2 days 19 hours ago) and read 17436 times:

Quoting alfablue (Reply 51):
That is taken into account in the regulations and there wisdom was wrong. Regulations state that on an ETOPS/LROPS flight the battery must assure a safe descent and emergency landing (which lasts roughly 30 minutes and could be a watering -- it does not say diversion in the regulations concerning battery duration versus fire depression for example. The regulators are very specific about those time limites systems.

I love it when a discussion gets technical. Time for some boring technical specs.
I'm a EASA specialist; not really FAA, so I'll quote from EASA.



These are the specs for certification under normal operations of large transport aircraft, as specified in CS25:

(AMC, acceptable means of compliance, means these are generally accepted ways to comply, I'm sure that if you want to run your own separate back-up generator with its separate fuel tank, it would be up to you.)

EASA explicitely depicts the role of the battery in this section:


AMC 25.1351(d)
Operation without Normal Electrical Power
1 Provision should be made to ensure adequate electrical supplies to those services, which are
necessary to complete the flight and make a safe landing in the event of a failure of all normal generated
electrical power. All components and wiring of the alternate supplies should be physically and electrically
segregated from the normal system and be such that no single failure, including the effects of fire, the
cutting of a cable bundle, the loss of a junction box or control panel, will affect both normal and alternate
supplies. CS-25 BOOK 2
2-F-46
2 When ensuring the adequacy of electrical supplies relative to alternate power source duration and
integrity, special consideration should be given to aeroplanes such as those with fly-by-wire, for which the
total loss of electrical supplies could result in an immediate loss of control.
3 In considering the services which should remain available following the loss of the normal generated
electrical power systems, consideration should be given to the role and flight conditions of the aeroplane and
the possible duration of flight time to reach an airfield and make a safe landing.
4 The services required by CS 25.1351(d)(1) may differ between aeroplane types and roles and
should be agreed with the Agency. These should normally include –
a. Attitude information;
b. Radio communication and intercommunication;
c. Navigation;
d. Cockpit and instrument lighting;
e. Heading, airspeed and altitude, including appropriate pitot head heating;
f. Adequate flight controls;
g. Adequate engine control; and
Restart capability with critical type fuel (from the standpoint of flame-out and restart capability) and with the
aeroplane initially at the maximum certificated altitude;
h. Adequate engine instrumentation;
i. Such warning, cautions and indications as are required for continued safe flight and landing;
j. Any other services required for continued safe flight and landing.
5 Consideration should also be given to the equipment and the duration of services required to make
a controlled descent and forced landing in the event of failure and inability to restart all engines.
6 Alternate Power Source Duration and Integrity
6.1 Time Limited. Where an alternate power source provided to comply with CS 25.1351(d) is time
limited (e.g. battery), the required duration will depend on the type and role of the aeroplane. Unless it can
be shown that a lesser time is adequate, such a power source should have an endurance of at least 60
minutes, at least 30 minutes of which is available under IMC. An endurance of less than 30 minutes under
IMC would not normally be acceptable. The endurances, with any associated procedures, should be
specified in the Flight Manual. The endurance time should be determined by calculation or test, due to
allowance being made for –


According to some posters, I don't know what I'm talking about, but it looks as if I know what EASA is talking about. As you can see above, batteries aren't there to transition between generation systems, they are there for the scenario of the main (AC) electrical system failure.

As for ETOPS and LROPS, give me more time to find the exact EASA provisions for the batteries. It could be that I'm wrong but I remember some certification inspector telling me that the battery has to cater for the power for an entire diversion


User currently offlinelightsaber From United States of America, joined Jan 2005, 13111 posts, RR: 100
Reply 61, posted (1 year 6 months 3 weeks 2 days 19 hours ago) and read 17388 times:
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Quoting moo (Reply 57):
Sure, the FAA may have mandated "one failure every 1 million flight hours", but that doesn't mean you cannot have two failures during any one period - it just means you cannot have more than X number failures in Y period.

Yea... but the stats were bad for the 787 that week with two fuel leaks, a cracked windshield, and the batteries. The fuel leaks were due to some bad maintenance and bad coatings on some valves. The windshield is something that will just happen to all aircraft, and then we talk about the batteries...


I do not think Boeing will be given a pass. I think they'll fly again by May though.

Lightsaber



Societies that achieve a critical mass of ideas achieve self sustaining growth; others stagnate.
User currently offlinercair1 From United States of America, joined Oct 2009, 1320 posts, RR: 52
Reply 62, posted (1 year 6 months 3 weeks 2 days 18 hours ago) and read 17282 times:
AIRLINERS.NET CREW
CUSTOMER SERVICE & SUPPORT

Quoting alfablue (Reply 51):
I don't think it's an engineering problem anymore to be honest -- the dimensions of this grounding are huge.

I agree that it is not "just" an engineering problem - and it is debatable which, the engineering or PR problem, is more difficult to address. Engineering responds to science, PR to emotion. As mjoelnir's comments so aptly prove, emotion can be very difficult to deal with.

Quoting alfablue (Reply 51):
That is taken into account in the regulations and there wisdom was wrong. Regulations state that on an ETOPS/LROPS flight the battery must assure a safe descent and emergency landing (which lasts roughly 30 minutes and could be a watering -- it does not say diversion in the regulations concerning battery duration versus fire depression for example. The regulators are very specific about those time limites systems.

Thank you. Perhaps you will be listened to.

Quoting mjoelnir (Reply 48):
So to talk facts.

You say there is NO WAY that the ac part of the electrical system goes down and does not come up and the batteries have to keep carrying the load of the flight instruments?
That means you have to be 100% sure for your statements.

Please refrain from misstating my positions.
I beginning to believe you are doing so with intent - to provoke arguments - rather than further discussion and understanding. While I object to that, it is your right to do so. It is also my right to respond, or not.

I never said this. It would be foolish for anybody to say any system on any aircraft at any time or any where is 100% guaranteed. I don't think I'm a fool, nor do I think you are.

What I said was that an electrical failure that totally wipes out the electrical system - in a manner that functioning generators and Rat cannot supply power - ever - will likely prevent the battery from delivering power. The most likely case that comes close is a fuel starvation one - in which the engine generators and APU become unavailable. That is not an electrical failure - and the RAT will come in there. If the RAT does not - I believe you have bigger problems because I believe the RAT provides hydraulic power that the battery cannot. In any case - a long term flight is not an option in that case - you are going down.
Now, it is theoretically possible you take off on a flight, the main battery fails, you run out of fuel and your RAT fails to operate. But we live in that world on every flight every day - 787 or not. There is always some 'scenario' that you can design that will result in loss of the aircraft. That is why I do not think that the current failure rate of the battery - if it is real - is a long term viable solution. As I have stated - or rather agreed with others who state it - I believe the most likely scenario is both improved containment and improved reliability. The containment is not a fix to reliability - it is extra insurance for a known failure mode. After the United DC-10 crashed in Souix City - they added check valves in the hydraulic lines to prevent total system loss in a future event - improved insurance. Response to a known failure. I believe that after the lost of the DC-10 (in Chicago?) due to slat retraction after damage to hydraulics in the wing, they modified the slat system to prevent that (I'm actually not sure - I do know that the fact that the slats required hydraulics to remain extended on the DC 10 was atypical.)

I do think the probability of a battery happening to fail and at the same time on the same plane all 7 other power sources become permanently unavailable is very small - but even so - the main battery is a required system for takeoff - just like an engine. If it fails in flight - I believe you are to divert and land - just like an engine (ignoring quads who have continued long flights - which I would not support).

Quoting mjoelnir (Reply 48):
I know there is redundancy I do not talk about that.

Then you are ignoring reality for the purposes of argument. Not interested.

[Edited 2013-02-25 06:51:29]


rcair1
User currently offline7BOEING7 From United States of America, joined Oct 2012, 1591 posts, RR: 8
Reply 63, posted (1 year 6 months 3 weeks 2 days 17 hours ago) and read 17038 times:

Quoting Wisdom (Reply 60):
6 Alternate Power Source Duration and Integrity
6.1 Time Limited. Where an alternate power source provided to comply with CS 25.1351(d) is time
limited (e.g. battery), the required duration will depend on the type and role of the aeroplane. Unless it can
be shown that a lesser time is adequate, such a power source should have an endurance of at least 60
minutes, at least 30 minutes of which is available under IMC. An endurance of less than 30 minutes under
IMC would not normally be acceptable. The endurances, with any associated procedures, should be
specified in the Flight Manual. The endurance time should be determined by calculation or test, due to
allowance being made for –

Good--The EASA alternate power source for the 787/777 is the RAT (with the battery as a "backup"), the alternate power source on the 737 is the battery with increased duration. Since with fuel exhaustion you're going down anyway, we'll just say that you dispatched with the APU INOP and lost all the engine generators (4). The Main battery powers essential instruments (as listed in the post) until the RAT deploys and powers the essential instruments. The Main battery goes back to sleep until required to power the brakes during rollout.

If the RAT fails to deploy, the Main battery will continue to power the essential instruments for 30 minutes until you're VMC and then you go dark in the cockpit but the engines are still running, you have hydraulic power and you can see where you are going-you just ca'n't talk and have to use dead reckoning to find some place to land.


User currently offlineAeroWesty From United States of America, joined Oct 2004, 20632 posts, RR: 62
Reply 64, posted (1 year 6 months 3 weeks 2 days 17 hours ago) and read 16935 times:

Quoting 7BOEING7 (Reply 63):
If the RAT fails to deploy, the Main battery will continue to power the essential instruments for 30 minutes until you're VMC and then you go dark in the cockpit but the engines are still running, you have hydraulic power and you can see where you are going-you just ca'n't talk and have to use dead reckoning to find some place to land.

Perhaps I'm just misreading this, but how do the engines still turn in the fuel exhaustion scenario you described?



International Homo of Mystery
User currently offlineKaiarahi From Canada, joined Jul 2009, 2998 posts, RR: 27
Reply 65, posted (1 year 6 months 3 weeks 2 days 17 hours ago) and read 16895 times:

Quoting Wisdom (Reply 60):

I believe you're misinterpreting the EASA requirements. On RAT aircraft, the RAT is the independent alternative source of power. The RAT is not time limited, so 6.1 does not apply.



Empty vessels make the most noise.
User currently offline7BOEING7 From United States of America, joined Oct 2012, 1591 posts, RR: 8
Reply 66, posted (1 year 6 months 3 weeks 2 days 17 hours ago) and read 16779 times:

Quoting AeroWesty (Reply 64):

Perhaps I'm just misreading this, but how do the engines still turn in the fuel exhaustion scenario you described?

When a jet engine runs out of fuel the fire goes out but the engine does not stop spinning--as opposed to a propeller driven airplane where you want the propeller in a "feathered" (least drag) stopped position. Although the jet engine doesn't spin fast enough to provide electrical power it will provide hydraulic power to a fairly low airspeed. On the 787/777 when hydraulic power is no longer available there are mechanical cables providing pitch and roll control through landing.


User currently offlinealfablue From Spain, joined Jan 2013, 43 posts, RR: 10
Reply 67, posted (1 year 6 months 3 weeks 2 days 17 hours ago) and read 16772 times:

Quoting Kaiarahi (Reply 65):
I believe you're misinterpreting the EASA requirements. On RAT aircraft, the RAT is the independent alternative source of power. The RAT is not time limited, so 6.1 does not apply.

I am posting the relevant regulations below. On an ETOPS/LROPS flight (in addition to what wisdom posted) with an aircraft equipped with a RAT -- "sufficient battery capacity should be provided to allow a controlled descent and emergency landing" -- as I said before the battery has to allow to do a watering from cruise in a worst case scenario but that applies if the RAT fails -- otherwise it assures controllability during the RAT deployment (elec transition).

Quoting EASA:


(c) Ram air turbine deployment should be demonstrated to be sufficiently
reliable and not require main electrical or engine-dependent power for
deployment.

NOTE:

(1) Following the loss of all normal generated electrical power,
continuity of electrical power for essential service (e.g. by use
of batteries) should be assured until the non-time limited
emergency or standby power source can be brought into
operation.

(2) If loss of all engines can prevent the operation of the non-time
limited power source, emergency or standby, sufficient battery
capacity should be provided to allow a controlled descent and
emergency landing.


alfaBlue


User currently offlinejustloveplanes From United States of America, joined Jul 2004, 1056 posts, RR: 1
Reply 68, posted (1 year 6 months 3 weeks 2 days 16 hours ago) and read 16776 times:

Quoting Revelation (Reply 56):
It seems one then have a perfect containment system, or one that's "not remotely likely" to fail, i.e. once in 10e6 flight hours. Should be interesting certifying that. I know you are saying that this type of design/analysis is routine, but still it should be interesting.

It is probably not totally trivial, but definitely a principle in common use, it's just a matter of how heavy Boeing wants to go. As a common reference point - how often do modern scuba tanks explode? The are filled to 3000 PSI time and again; lots of those in use, and that's a reasonably low cost aluminum vice the titanium/steel application Boeing is considering. Titanium should withstand the heat generated.


User currently offline7BOEING7 From United States of America, joined Oct 2012, 1591 posts, RR: 8
Reply 69, posted (1 year 6 months 3 weeks 2 days 16 hours ago) and read 16801 times:

Quoting AeroWesty (Reply 64):

Perhaps I'm just misreading this, but how do the engines still turn in the fuel exhaustion scenario you described?


The engine "windmills" due to the airflow through it--faster or slower depending on the speed of the aircraft.

[Edited 2013-02-25 08:51:50]

User currently offlineKaiarahi From Canada, joined Jul 2009, 2998 posts, RR: 27
Reply 70, posted (1 year 6 months 3 weeks 2 days 16 hours ago) and read 16749 times:

Read carefully, the requirement describes precisely the 787 system:

Quoting alfablue (Reply 67):
(1) Following the loss of all normal generated (i.e. from the generators) electrical power,
continuity of electrical power for essential service (e.g. by use of batteries) should be assured until the non-time limited
emergency or standby power source
(i.e. RAT) can be brought into operation.
Quoting alfablue (Reply 67):
(2) If loss of all engines can prevent the operation of the non-time limited power source, emergency or standby (i.e. RAT), sufficient battery capacity should be provided to allow a controlled descent and
emergency landing.

The second requirement does not apply as loss of all engines does not prevent RAT deployment on the 787.



Empty vessels make the most noise.
User currently offlineAeroWesty From United States of America, joined Oct 2004, 20632 posts, RR: 62
Reply 71, posted (1 year 6 months 3 weeks 2 days 16 hours ago) and read 16666 times:

Quoting 7BOEING7 (Reply 69):
The engine "windmills" due to the airflow through it--faster or slower depending on the speed of the aircraft.

Ah, thank you. I understood about the windmilling part, but didn't know that in that state it provided any useful power to any system on the aircraft.



International Homo of Mystery
User currently offlinealfablue From Spain, joined Jan 2013, 43 posts, RR: 10
Reply 72, posted (1 year 6 months 3 weeks 2 days 16 hours ago) and read 16637 times:

Quoting Kaiarahi (Reply 70):
The second requirement does not apply as loss of all engines does not prevent RAT deployment on the 787

I am not a lawyer but I interpret it differently as this section of the Regulations does not apply to batteries as such but refers to the RAT and its outlined that it has to be independent in its deployment of the main electrical system and engines (so the generators or main bus). I read the "can prevent" in the second note not as a causal requirement. I read it as "if both happens than" kind of thing. Anyway for sure the battery is designed to allow and fullfil that requirement nevertheless -- I am certain the 787 can be flown on BAT only for at least 30 min.

After all and we haven't discussed that and I don't know it to be honest but in the Airbus you have certain smoke (avionics smoke procedure) where you do bring yourself on purpose into an ELEC emergency configuration. The role of the battery even if hardly used in normal operation is very complex.

alfaBlue


User currently offlineWisdom From , joined Dec 1969, posts, RR:
Reply 73, posted (1 year 6 months 3 weeks 2 days 14 hours ago) and read 16331 times:

alfablue, regarding ETOPS/LROPS, I found the relevant section:

AMC 20-6 rev. 2 Effective: 23/12/2010
Annex II to ED Decision 2010/012/R of 16/12/2010
AMC 20-6 rev. 2
Extended Range Operation with Two-Engine Aeroplanes ETOPS Certification and
Operation

Chapter II TYPE DESIGN APPROVAL CONSIDERATIONS
SECTION 7: EVALUATION CRITERIA OF THE ETOPS TYPE DESIGN


(8) Three or more reliable and independent electrical power sources should be available. As a minimum, following failure of any two sources, the remaining source should be capable of powering the items specified in paragraph (7). If one or more of the required electrical power sources are provided by an APU, hydraulic system, or ram air turbine, the following criteria apply as appropriate:
(i) The APU, when installed, should meet the criteria in paragraph (4).
(ii) The hydraulic power source should be reliable. To achieve this reliability, it may be necessary to provide two or more independent energy sources (e.g., bleed air from two or more pneumatic sources).
(iii) The Ram Air Turbine (RAT) should be demonstrated to be sufficiently reliable in
deployment and use. The RAT should not require engine dependent power for
deployment.
If one of the required electrical power sources is provided by batteries, the following
criteria apply:
(iv) When one of the 3 independent electrical power sources is time-limited (e.g.
batteries), such power source should have a capability to enable the items required in paragraph (7) to be powered for continued flight and landing to an ETOPS enroute alternate aerodrome and it will be considered as a time-limited system in accordance with paragraph (12).
(9) For ETOPS approvals above 180 minutes, in addition to the criteria for electrical power sources specified in paragraph (8) above, the following criteria should also be
applied:
(i) Unless it can be shown that the failure of all 3 independent power sources required by paragraph (8) above is extremely improbable, following failure of these 3 independent power sources, a fourth independent power source should be available that is capable of providing power to the essential functions referred to in paragraph (7) for continued safe flight and landing to an adequate ETOPS en-route alternate aerodrome
(ii) If the additional power source is provided by an APU, it should meet the criteria in paragraph (4).
(iii) If the additional power source is provided by a hydraulic system or ram air turbine, the provisions of paragraph (8) apply.



Paragraph 4 on the APU:

The APU installation, if required for extended range operations, should meet the applicable CS-25 provisions (Subpart J, APU) and any additional requirements necessary to demonstrate its ability to perform the intended function as specified by the Agency following a review of the applicant's data. If certain extended range operation may necessitate in-flight start and run of the APU, it must be substantiated that the APU has adequate capability and reliability for that operation.
The APU should demonstrate the required in-flight start reliability throughout the flight envelope (compatible with overall safety objective but not less than 95%) taking account of all approved fuel types and temperatures. An acceptable procedure for starting and running the APU (e.g. descent to allow start) may be defined in order to demonstrate compliance to the required in-flight start reliability. If this reliability cannot be demonstrated, it may be necessary to require continuous operation of the APU.



I interpret this as follows.
At any given time, you need 4 viable and independent sources of electrical power for more than ETOPS 180.
Engine 1, Engine 2, RAT, APU.

However, the B787's APU battery is shown to be unreliable, which means that unless the APU is started before the ETOPS flight's "ETOPS" section (or the full flight, depending on what level of safety the regulators want to achieve), the 4th source of electrical power would be the battery, which should be able to provide sufficient power for a full diversion and be reliable.

In that case, the reliability of the batteries would weigh on the ETOPS.

One thing that I would like to add: do not forget that EASA certification requirements will be applied in the EU, but some countries in the EU can impose stricter rules regarding ETOPS operations or other operating standards.

On twin ETOPS aircraft that are not equipped with a RAT, your battery needs to provide sufficient juice for your full diversion.


User currently offlinerwessel From United States of America, joined Jan 2007, 2351 posts, RR: 2
Reply 74, posted (1 year 6 months 3 weeks 2 days 13 hours ago) and read 16018 times:
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Quoting Wisdom (Reply 73):
I interpret this as follows.
At any given time, you need 4 viable and independent sources of electrical power for more than ETOPS 180.
Engine 1, Engine 2, RAT, APU.

No, it quite clearly says you need three, unless failure of all three is not "extremely improbable".

Quoting Wisdom (Reply 73):
However, the B787's APU battery is shown to be unreliable, which means that unless the APU is started before the ETOPS flight's "ETOPS" section (or the full flight, depending on what level of safety the regulators want to achieve), the 4th source of electrical power would be the battery, which should be able to provide sufficient power for a full diversion and be reliable.

The APU can start off engine power if any one of the four engine driven generators is working, or off the RAT, or off the APU battery. And the 787's APU starts automatically when one of the engine driven generators trips off. You can dispatch a flight without an APU battery at all, although it's possible that may have an ETOPS impact. But getting back to the extremely improbable thing, it's only an issue if the odds of having a battery failure combined with the odds of a failure the other ways of starting the APU is not "extremely improbable".

Quoting mjoelnir (Reply 55):
So not to talk around the bush, the failure rate, 2 in 50.000 hours, exhibited by those batteries is low enough regarding the electrical safety part?
That is would your not exactly true implies.

As I said, I don't know the failure rates of the rest of the system, so I can't say for sure what the FAA is looking for. Since you don't either, your statement, claiming "the FAA will want a reduced failure rate compared to what has happened, even if the containment is acceptable”, is less than exactly true.

In any event, the odds of a main battery failure are not (to badly overuse the limited dataset) two in 50,000 hours, rather *one* in 50,000 hours. There are two batteries on board, which doubles the failure rate of batteries on board (hence a battery failure every 25,000 hours), but not the failure rate for any one battery. So let's (very crudely) take the 1-in-50000 hours main battery failure rate, then so long as the battery is not needed more than once every 20,000 hours, you've got your one-in-a-billion requirement.

Obviously that's far too simplistic, the confidence interval around the battery failure rate is quite large at the moment, nor is it taking into account that the battery has more than a dozen hours in which to fail on a long flight before the electrical system might pack it in (so there's a time in which the battery failures can effectively accumulate). But that's the general idea. OTOH, I can't imagine that the rate of such severe failures of the main electrical system is anywhere near 1-in-20000 hours.


User currently offlinelightsaber From United States of America, joined Jan 2005, 13111 posts, RR: 100
Reply 75, posted (1 year 6 months 3 weeks 2 days 13 hours ago) and read 16050 times:
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Quoting Wisdom (Reply 73):
(9) For ETOPS approvals above 180 minutes, in addition to the criteria for electrical power sources specified in paragraph (8) above, the following criteria should also be
applied:
(i) Unless it can be shown that the failure of all 3 independent power sources required by paragraph (8) above is extremely improbable, following failure of these 3 independent power sources, a fourth independent power source should be available that is capable of providing power to the essential functions referred to in paragraph (7) for continued safe flight and landing to an adequate ETOPS en-route alternate aerodrome

Thank you. That implies ETOPS 180+ will have to be revisited.   I suspected so, but I didn't have the exact regulation in front of me.

Lightsaber



Societies that achieve a critical mass of ideas achieve self sustaining growth; others stagnate.
User currently offlineXT6Wagon From United States of America, joined Feb 2007, 3409 posts, RR: 4
Reply 76, posted (1 year 6 months 3 weeks 2 days 12 hours ago) and read 15886 times:

Quoting lightsaber (Reply 75):
Thank you. That implies ETOPS 180+ will have to be revisited.   I suspected so, but I didn't have the exact regulation in front of me.

nope, the failure chance of the primary electrical system is so small, coupled with the failure rate of the APU being also extremely rare means that the battery system can be quite frequent and still meet this requirement as written.

not to say the regulators would demand more than what written.


User currently offline7BOEING7 From United States of America, joined Oct 2012, 1591 posts, RR: 8
Reply 77, posted (1 year 6 months 3 weeks 2 days 12 hours ago) and read 15889 times:

Quoting lightsaber (Reply 75):
Thank you. That implies ETOPS 180+ will have to be revisited. I suspected so, but I didn't have the exact regulation in front of me.

In my understanding the 787 already has ETOPS 180 and ETOPS 180+ has not been granted yet so it doesn't have to be revisited.
.
Assuming the battery issue makes the APU an unreliable source you still have the RAT which combined with the two engines gives you 3 sources which I believe would provide the necessary extremely improbable failure rate therefore 4 sources are not required. If the APU is required for ETOPS 180 or ETOPS 180+ (in the 777) now it would seem the two engines + RAT don't meet the extremely improbable requirement. Can somebody speak to current airline ETOPS/APU requirements for the 777?


User currently offlinercair1 From United States of America, joined Oct 2009, 1320 posts, RR: 52
Reply 78, posted (1 year 6 months 3 weeks 2 days 12 hours ago) and read 15853 times:
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Quoting alfablue (Reply 72):
I am not a lawyer but I interpret it differently as this section of the Regulations does not apply to batteries as such but refers to the RAT and its outlined that it has to be independent in its

I'm not a lawyer either - though somebody accused me of sounding like one the other day.  
However, I do spend inordinate amounts of time reading a form of legalese - ie. patents - and arguing with lawyers (both friendly and adversarial).

Quoting Kaiarahi (Reply 70):
2) If loss of all engines can prevent the operation of the non-time limited power source, emergency or standby (i.e. RAT), sufficient battery capacity should be provided to allow a controlled descent and
emergency landing.

If this language were in a claim on a patent - it would certainly be interpreted as causal. In other words - if the loss of all engines _can cause_ a failure of the non-time limited power source to operate - then you need battery power to allow a controlled descent. Nothing about the 787 engines can prevent deployment of the RAT - so it is not the case.
Even in a fuel starvation case - if you were relying on the APU as a non-time limited source (funny language in itself, since you are most certainly time limited - by fuel) loss of the engines due to fuel starvation would not prevent the APU from operating. The APU would not operate due to a common failure - no fuel. And you still have the RAT. Nothing that has happened will prevent the RAT from deploying and operating.

Now - I believe this is the EASA requirement - so I wonder what the original (and therefore authoritative) language is. Is is French? I run into cases where nuances like this are changed in translation of foreign patents into English all the time - and they are a real headache. Interesting question.

Quoting Wisdom (Reply 73):
I interpret this as follows.
At any given time, you need 4 viable and independent sources of electrical power for more than ETOPS 180.
Engine 1, Engine 2, RAT, APU.

I disagree. You only need 4 viable and independent sources of electrical power in the case covered by
"(i) Unless it can be shown that the failure of all 3 independent power sources required by paragraph (8) above is extremely improbable" cannot be shown.

In other words - you must show that loss of all 3 independent power sources required is extremely improbable.

Those independent sources are the engines, APU and Rat. The battery is not one. In fact, I think the engines are each considered 'independent' sources - so you have 4. The only factor that could make them non-independent is fuel - and in that case, the APU is also not independent. I don't think there are any planes that consider power from both engines and the APU as a "single, non-independent source".

Quoting Wisdom (Reply 73):
On twin ETOPS aircraft that are not equipped with a RAT, your battery needs to provide sufficient juice for your full diversion.

I believe that is correct. As I think it was stated here.

Quoting 7BOEING7 (Reply 63):
the alternate power source on the 737 is the battery with increased duration.
Quoting Wisdom (Reply 73):
However, the B787's APU battery is shown to be unreliable, which means that unless the APU is started before the ETOPS flight's "ETOPS" section (or the full flight, depending on what level of safety the regulators want to achieve), the 4th source of electrical power would be the battery, which should be able to provide sufficient power for a full diversion and be reliable.

The APU battery is not required for flight. You can take off without it. One reason both the APU and Main batteries are identical is so that you can move the APU battery into the main spot if the main battery goes down - and still dispatch.
I'm not sure if that is true for ETOPs and in particular for ETOPs >180. It may be the APU battery is required in that case, but I think not. You may need to have the APU running if you dispatch ETOPS with no apu battery - but since you can start the apu from either of the engines - I doubt it. Again - the only likely cause for simultaneous loss of both engines is fuel. and that would take out the APU. In the other recent case where both engines went (Cactus 1549), the APU was started. However, I'd have to go back and study to see if that was required for what they did. I believe the battery and Rat would have sufficed.
Does anybody know if you can start the 787 APU with the Rat? (I doubt it).

Now - if we are getting into the realm of:
1) You dispatch your 787 with a bad APU battery and functioning Main battery.
2) Your main battery goes belly up right away.
3) Before you can divert - you loose both engines at 3000 ft due to bird strikes.
4) Your engines go quickly enough you cannot start your APU.
5) The bird jams your RAT
Well then - really bad day....



rcair1
User currently offlineKaiarahi From Canada, joined Jul 2009, 2998 posts, RR: 27
Reply 79, posted (1 year 6 months 3 weeks 2 days 11 hours ago) and read 15665 times:

Quoting rcair1 (Reply 78):
Now - I believe this is the EASA requirement - so I wonder what the original (and therefore authoritative) language is. Is is French? I run into cases where nuances like this are changed in translation of foreign patents into English all the time - and they are a real headache. Interesting question.

EASA has 22 official languages. The agency's working language is English, but the requirement may have been first drafted internally in another language and then translated - no way of knowing. I'll check out the French and German versions when I get a free moment. This was an interesting issue on the AF447 threads, where posters were parsing in detail the English translation of the CVR transcript as if it were what the pilots actually said.

Quoting rcair1 (Reply 78):
Nothing about the 787 engines can prevent deployment of the RAT - so it is not the case.

We're in agreement.



Empty vessels make the most noise.
User currently offlinepacksonflight From Iceland, joined Jan 2010, 381 posts, RR: 0
Reply 80, posted (1 year 6 months 3 weeks 2 days 11 hours ago) and read 15647 times:

Quoting rcair1 (Reply 78):
Now - if we are getting into the realm of:
1) You dispatch your 787 with a bad APU battery and functioning Main battery.
2) Your main battery goes belly up right away.
3) Before you can divert - you loose both engines at 3000 ft due to bird strikes.
4) Your engines go quickly enough you cannot start your APU.
5) The bird jams your RAT
Well then - really bad day....

What is the meaning with all this?? Are you really saying you can dispatch the 787 with only one battery?? sounds rather funny to me.


User currently offline7BOEING7 From United States of America, joined Oct 2012, 1591 posts, RR: 8
Reply 81, posted (1 year 6 months 3 weeks 2 days 11 hours ago) and read 15621 times:

Quoting packsonflight (Reply 80):
Are you really saying you can dispatch the 787 with only one battery??

Answer: Yes


User currently offlineWisdom From , joined Dec 1969, posts, RR:
Reply 82, posted (1 year 6 months 3 weeks 2 days 11 hours ago) and read 15627 times:

Quoting XT6Wagon (Reply 76):
nope, the failure chance of the primary electrical system is so small, coupled with the failure rate of the APU being also extremely rare means that the battery system can be quite frequent and still meet this requirement as written.

The issue is not the failure rate of the APU, but the "failure to start the APU rate" if the APU battery is not reliable.

It means that the 4th electrical system, whether the battery or the APU (including its starting battery), must be reliable, in other words, the battery needs to be reliable.

Quoting rwessel (Reply 74):
The APU can start off engine power if any one of the four engine driven generators is working, or off the RAT, or off the APU battery. And the 787's APU starts automatically when one of the engine driven generators trips off. You can dispatch a flight without an APU battery at all, although it's possible that may have an ETOPS impact. But getting back to the extremely improbable thing, it's only an issue if the odds of having a battery failure combined with the odds of a failure the other ways of starting the APU is not "extremely improbable".

I don't get your point. If you have one engine that can provide power to start an APU, why would you consider the APU as necessary at all? It will add comfort for sure, but would it be essential?

Quoting rwessel (Reply 74):
Quoting Wisdom (Reply 73):
I interpret this as follows.
At any given time, you need 4 viable and independent sources of electrical power for more than ETOPS 180.
Engine 1, Engine 2, RAT, APU.

No, it quite clearly says you need three, unless failure of all three is not "extremely improbable".

Here, the issue is not whether engines are providing thrust for continued flight.
Generators do get swapped more often than engines, electrics do go haywire from time to time, and a lot of additional factors play a role on top of the engine failure factor.
But remember that the probabilibty requirements here will be more stringent than for single engine failures, while having more chances of something going wrong (engine failure factors, plus generator failure factor, plus electrical failure factor, plus additional external factors, and so on...)

Because even if both engines fail, you can ditch or make a forced landing. But maintaining essential electrics is essential to a successful emergency landing, no matter how bad a day you're having.


My opinion is that given failure rates of the B787 batteries, it would not be a responsible solution to just reinforce the containment.

Actually, if you see the containment reinforcement as a sufficient fix regardless of reliability of the battery, please explain to me why you would need a main battery at all and not remove it to get it over with?
Even considering an unlikely dual engine failure:
The rat will still work and will take only seconds to deploy (engines take time to spool down during failures so generators still provide power for those several seconds), the APU will still fire up within 30-200 seconds (well sorry if I said 10 seconds, on older aircraft those APU's do fire up quickly and always felt to me like it was only 10 seconds. On A320's, it takes forever until the apu gen becomes available), you would still maintain uninterrupted instruments operation through any of these means.


Furthermore, CS25 states:

CS 25.1353
(c) Storage batteries must be designed and installed as follows:
(1) Safe cell temperatures and pressures must be maintained during any probable charging or discharging condition. No uncontrolled increase in cell temperature may result when the battery is recharged (after previous complete discharge)

[Edited 2013-02-25 14:26:03]

User currently offlineStitch From United States of America, joined Jul 2005, 30978 posts, RR: 86
Reply 83, posted (1 year 6 months 3 weeks 2 days 11 hours ago) and read 15625 times:
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Quoting packsonflight (Reply 80):
Are you really saying you can dispatch the 787 with only one battery?
Quoting Wisdom (Reply 82):
The issue is not the failure rate of the APU, but the "failure to start the APU rate" if the APU battery is not reliable.

In normal 787 APU-start operations via battery only, the Ship's and APU battery together start the APU. You can dispatch without the APU battery because the Ship's Battery can start the APU (the Ship's and APU batteries are identical).


User currently offline7BOEING7 From United States of America, joined Oct 2012, 1591 posts, RR: 8
Reply 84, posted (1 year 6 months 3 weeks 2 days 11 hours ago) and read 15556 times:

Quoting Stitch (Reply 83):
In normal 787 APU-start operations via battery only, the Ship's and APU battery together start the APU. You can dispatch without the APU battery because the Ship's Battery can start the APU (the Ship's and APU batteries are identical).

That may be possible but I believe if you remove the APU battery the APU is deemed INOP. Anybody got an MEL?


User currently offlineStitch From United States of America, joined Jul 2005, 30978 posts, RR: 86
Reply 85, posted (1 year 6 months 3 weeks 2 days 10 hours ago) and read 15510 times:
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Quoting 7BOEING7 (Reply 84):
That may be possible but I believe if you remove the APU battery the APU is deemed INOP.

Why would you deem it INOP? You'd normally start it by using the engine generators in flight or using ground power at the gate. Even in a fuel starvation situation, both engines don't fail simultaneously so even if one engine flamed out, you could still start the APU using the generators from the other engine (unless you dawdled, which one would hope the flight crew would not).


User currently offlinemjoelnir From Iceland, joined Feb 2013, 1449 posts, RR: 2
Reply 86, posted (1 year 6 months 3 weeks 2 days 10 hours ago) and read 15365 times:

I thing all of you are tip toeing around the possibility of electrical as opposed to a generating failure.

Ok you have generation pretty well covered, first engine with two generators, second engine with two generators, apu with two generators, rat and battery for transition, quite a line up when you do not forget to fill up the tanks.

But as I said before, an electrical failure instead of an generating failure.
Produced by a lightning strike, electrical fire, something unknown.
Generation is running AC to DC conversion is down.
How many redundancies are there.
There are at least two independent systems yes, but say both go down, is the battery not a reserve fitted into fault tree?
And is it more unlikely than both engines going out?
How similar are the redundant systems?
Do they use the similar hardware or different hardware?


User currently offlineXT6Wagon From United States of America, joined Feb 2007, 3409 posts, RR: 4
Reply 87, posted (1 year 6 months 3 weeks 2 days 10 hours ago) and read 15361 times:

Quoting Stitch (Reply 85):
so even if one engine flamed out, you could still start the APU using the generators from the other engine (unless you dawdled, which one would hope the flight crew would not).

someone else stated that the APU will auto start when a generator goes offline. So I'm not sure that the pilots attention would even be needed.

Quoting Wisdom (Reply 82):
The issue is not the failure rate of the APU, but the "failure to start the APU rate" if the APU battery is not reliable.

Its been stated multiple times that the APU doesn't need the battery to start. The APU should be running well before you ever need the battery unless you find a fault that offlines pretty much the entire electrical system in one single fault. If you missed it, thats why Boeing redid the software and hardware after the fire on test plane.

More to the point you keep demanding insane levels of redundancy and low risk. We are talking the levels of "NEVER HAPPENED IN THE HISTORY OF FLIGHT" here. Perhaps we need to go back to 4+ engine bi-plane design to ensure the level of redundancy in those systems that you want in the electrical system.


User currently offlinemjoelnir From Iceland, joined Feb 2013, 1449 posts, RR: 2
Reply 88, posted (1 year 6 months 3 weeks 2 days 9 hours ago) and read 15302 times:

Quoting XT6Wagon (Reply 87):
More to the point you keep demanding insane levels of redundancy and low risk. We are talking the levels of "NEVER HAPPENED IN THE HISTORY OF FLIGHT" here. Perhaps we need to go back to 4+ engine bi-plane design to ensure the level of redundancy in those systems that you want in the electrical system.

We are talking about a new type of battery used the first time in an commercial air plain showing a lower reliability than the types used up to now.
Talking about that and why a reliable battery configuration is needed is hardly talking about insane levels of redundancy and low risk.


User currently offlineStitch From United States of America, joined Jul 2005, 30978 posts, RR: 86
Reply 89, posted (1 year 6 months 3 weeks 2 days 9 hours ago) and read 15324 times:
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Quoting mjoelnir (Reply 86):
I thing all of you are tip toeing around the possibility of electrical as opposed to a generating failure.

The engine and APU generators all feed the 230Vac system while the batteries feed the 28Vdc system. So if you lose the 230Vac system (VF AC BUS1 and VF AC BUS2) for whatever reason, the batteries are not going to be of any help energizing anything powered from that system.


User currently offlinemjoelnir From Iceland, joined Feb 2013, 1449 posts, RR: 2
Reply 90, posted (1 year 6 months 3 weeks 2 days 9 hours ago) and read 15295 times:

Quoting Stitch (Reply 89):
The engine and APU generators all feed the 230Vac system while the batteries feed the 28Vdc system. So if you lose the 230Vac system (VF AC BUS1 and VF AC BUS2) for whatever reason, the batteries are not going to be of any help energizing anything powered from that system.

You are still nearly talking about generating.

Lets say you lose the rectifiers/AC DC converters. 230V are still up 28V DC is down.


User currently offlineWisdom From , joined Dec 1969, posts, RR:
Reply 91, posted (1 year 6 months 3 weeks 2 days 9 hours ago) and read 15283 times:

Quoting XT6Wagon (Reply 87):
More to the point you keep demanding insane levels of redundancy and low risk. We are talking the levels of "NEVER HAPPENED IN THE HISTORY OF FLIGHT" here. Perhaps we need to go back to 4+ engine bi-plane design to ensure the level of redundancy in those systems that you want in the electrical system.

Remember that a B767 has 2 engines, 1 APU, 1 RAT (flight controls), 1 Hydraulic-driven generator, 1 reliable main battery, 1 reliable APU battery, and a bleed-air system for pressurisation and anti-ice.

So excuse me for asking too much of the 787's batteries.

Never happened in the history of flight? Complete AC system failures have occurred many times in the history of flight, combine that with unreliable batteries and you have a formula for the perfect storm. No AC power thus no power to the APU, no APU start due to a battery that has a mind of its own, no pressurisation, a RAT that could fail to deploy, freeze up, or be subject to a bird strike and a main battery that may or may not work, depends on how bad a day you're having.

Worst of all, most of these things seem to always happen at the same time.
So again... sorry for being too careful. I'm sure that the B787 is so great that it would fly safely on only one of both wings.


User currently offlinekanban From United States of America, joined Jan 2008, 3547 posts, RR: 26
Reply 92, posted (1 year 6 months 3 weeks 2 days 9 hours ago) and read 15188 times:
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Quoting Wisdom (Reply 91):
unreliable batteries a

Seems to me that we have (based on hours in use) reliable batteries, with two having had a problem. I have seen no reports of the 787 requiring battery use and not getting it.

I also learned that wisdom comes from learning and actual life experience... and there seems to be a disconnect here.


User currently offlinercair1 From United States of America, joined Oct 2009, 1320 posts, RR: 52
Reply 93, posted (1 year 6 months 3 weeks 2 days 9 hours ago) and read 15183 times:
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Quoting packsonflight (Reply 80):
What is the meaning with all this?? Are you really saying you can dispatch the 787 with only one battery?? sounds rather funny to me.

Yes - the APU battery is not required by the minimum equipment list. That is why the APU battery and main battery are identical. It was designed that way so if the main battery went inop - you could move the apu battery to that location and still operate the aircraft.

Quoting Wisdom (Reply 82):
if the APU battery is not reliable.

See above.

Quoting Wisdom (Reply 82):
I don't get your point. If you have one engine that can provide power to start an APU, why would you consider the APU as necessary at all? It will add comfort for sure, but would it be essential?

Redundancy. In the 787 if you loose an engine (or maybe just one generator on one engine), the APU will start automatically.

Quoting Wisdom (Reply 82):
Actually, if you see the containment reinforcement as a sufficient fix regardless of reliability of the battery...

I never said it was a sufficient fix. I think improvement in the battery reliability will be required eventually - however I think it is likely that they will be staged. However, I have no data to support that claim and neither do you to refute. Opinions a plenty - no data. We will find out. BTW - I think it is entirely possible that the battery improvement program will be much lower profile.

The question is how soon.

The 2 issues are separate. One is reliability of the battery as a power source, the second is containment of a potential or real fire.

Quoting Wisdom (Reply 82):
... please explain to me why you would need a main battery at all and not remove it to get it over with?

No - I'm not going to explain every thing somebody else invents and attributes to me- particularly when it is absurd.   
You explain the equivalence of no battery versus one that is something that has a very low failure rate - and will likely get better.



rcair1
User currently offlineStitch From United States of America, joined Jul 2005, 30978 posts, RR: 86
Reply 94, posted (1 year 6 months 3 weeks 2 days 8 hours ago) and read 15133 times:
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Quoting mjoelnir (Reply 90):
Lets say you lose the rectifiers/AC DC converters. 230V are still up 28V DC is down.

If some event took out the Transformer Rectifier Unit and both Remote Power Distribution Units, I would not be surprised if it would affect the 28Vdc system to the point the batteries wouldn't be able to energize any of it.


User currently offline7BOEING7 From United States of America, joined Oct 2012, 1591 posts, RR: 8
Reply 95, posted (1 year 6 months 3 weeks 2 days 8 hours ago) and read 15094 times:

Quoting XT6Wagon (Reply 87):
Its been stated multiple times that the APU doesn't need the battery to start.

Yes the APU can be started in many different ways, however, nobody (with credentials) has confirmed whether the APU can be started without the APU battery in the airplane. Anybody with access to a 787 MEL/DDPG please speak up.

Quoting rcair1 (Reply 93):
Redundancy. In the 787 if you loose an engine (or maybe just one generator on one engine), the APU will start automatically.

If three or more engine generators go offline it starts.


User currently offlineWisdom From , joined Dec 1969, posts, RR:
Reply 96, posted (1 year 6 months 3 weeks 2 days 8 hours ago) and read 15042 times:

Quoting 7BOEING7 (Reply 95):
Yes the APU can be started in many different ways, however, nobody (with credentials) has confirmed whether the APU can be started without the APU battery in the airplane. Anybody with access to a 787 MEL/DDPG please speak up.

From the MMEL on the FAA website:
http://fsims.faa.gov/PICDetail.aspx?...d=99F881A26E3108C186257ABC00525F34

-31-01
APU Battery
C
1
0
(M)(O) May be inoperative provided:
a) VFSG systems operate normally, and
b) Flight remains within 180 minutes of landing at a suitable airport.


User currently offlinercair1 From United States of America, joined Oct 2009, 1320 posts, RR: 52
Reply 97, posted (1 year 6 months 3 weeks 2 days 8 hours ago) and read 15041 times:
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Quoting 7BOEING7 (Reply 95):
Yes the APU can be started in many different ways, however, nobody (with credentials) has confirmed whether the APU can be started without the APU battery in the airplane. Anybody with access to a 787 MEL/DDPG please speak up.

From the article in Aero_Q407 magazine (Boeing).

"The power source for APU starting may be the airplane battery, a ground power source, or an engine-driven generator. The power source for engine starting may be the APU generators, engine-driven generators on the opposite side engine, or two forward 115 VAC ground power sources. The aft external power receptacles may be used for a faster start, if desired."



rcair1
User currently offlineWisdom From , joined Dec 1969, posts, RR:
Reply 98, posted (1 year 6 months 3 weeks 2 days 8 hours ago) and read 15055 times:

Quoting rcair1 (Reply 97):
From the article in Aero_Q407 magazine (Boeing).

"The power source for APU starting may be the airplane battery, a ground power source, or an engine-driven generator. The power source for engine starting may be the APU generators, engine-driven generators on the opposite side engine, or two forward 115 VAC ground power sources. The aft external power receptacles may be used for a faster start, if desired."

It doesn't matter. The MMEL that I posted at reply96 says, "no APU battery, no ETOPS".

An unreliable APU battery (replaced at an estimated average of every 500 hours) is the same as no battery.
If you don't agree, argue it with the FAA.

[Edited 2013-02-25 17:28:32]

User currently offlineStitch From United States of America, joined Jul 2005, 30978 posts, RR: 86
Reply 99, posted (1 year 6 months 3 weeks 2 days 8 hours ago) and read 15119 times:
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Quoting 7BOEING7 (Reply 95):
Yes the APU can be started in many different ways, however, nobody (with credentials) has confirmed whether the APU can be started without the APU battery in the airplane.

That's already been confirmed by tdscanuck and CM. It is done by using one of the engine generators. This is also stated in in an article in the Q4_2007 issue of Aero Magazine.

Quote:
The power source for APU starting may be the airplane battery, a ground power source, or an engine-driven generator.




The 787 may also be dispatched with APU START SYS faults provided APU is started before departure and operated continuously throughout the flight.



Quoting Wisdom (Reply 98):
The MMEL that I posted at reply96 says, "no APU battery, no ETOPS".

Uh, it says "Flight remains within 180 minutes of landing at a suitable airport."

That's ETOPS-180.

[Edited 2013-02-25 17:31:54]

User currently offlinetugger From United States of America, joined Apr 2006, 5589 posts, RR: 8
Reply 100, posted (1 year 6 months 3 weeks 2 days 8 hours ago) and read 15083 times:

Quoting Wisdom (Reply 98):
It doesn't matter. The MMEL that I posted at reply96 says, "no APU battery, no ETOPS".

Then I am reading what you posted incorrectly? Your quote noted ETOPS180:

Quoting Wisdom (Reply 96):
b) Flight remains within 180 minutes of landing at a suitable airport.

What ETOPS is the 787 currently certed for?

Tugg



I don’t know that I am unafraid to be myself, but it is hard to be somebody else. -W. Shatner
User currently offline7BOEING7 From United States of America, joined Oct 2012, 1591 posts, RR: 8
Reply 101, posted (1 year 6 months 3 weeks 2 days 8 hours ago) and read 15096 times:

Quoting Wisdom (Reply 96):
From the MMEL on the FAA website:
http://fsims.faa.gov/PICDetail.aspx?...d=99F881A26E3108C186257ABC00525F34

-31-01
APU Battery
C
1
0
(M)(O) May be inoperative provided:
a) VFSG systems operate normally, and
b) Flight remains within 180 minutes of landing at a suitable airport.

Excellent, is that a public link? Is there a DDPG there also, the (M) & (O) indicate there are some maintenance and operational procedures that must be accomplished.

Quoting rcair1 (Reply 97):
From the article in Aero_Q407 magazine (Boeing).

"The power source for APU starting may be the airplane battery, a ground power source, or an engine-driven generator. The power source for engine starting may be the APU generators, engine-driven generators on the opposite side engine, or two forward 115 VAC ground power sources. The aft external power receptacles may be used for a faster start, if desired."

True, however that is written based on normal system configuration--not with a missing battery.


User currently offlineStitch From United States of America, joined Jul 2005, 30978 posts, RR: 86
Reply 102, posted (1 year 6 months 3 weeks 2 days 8 hours ago) and read 15393 times:
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Quoting tugger (Reply 100):
What ETOPS is the 787 currently certed for?

ETOPS-180 per the FAA and EASA TCDS.

FAA:

Quote:
The 787 has been evaluated in accordance with 14 CFR § 25.1535 and found suitable for 180-minute Extended Range Operations with Two-Engine Airplanes (ETOPS) when operated and maintained in accordance with Boeing Document No. D021Z002-01, “Model 787 ETOPS Configuration, Maintenance, and Procedures.”

EASA:

Quote:
The 787-8 has been evaluated in accordance with CS 25.1535 and found suitable for 180-minute Extended Range Operations with Two-Engine Airplanes (ETOPS).


User currently offlinetugger From United States of America, joined Apr 2006, 5589 posts, RR: 8
Reply 103, posted (1 year 6 months 3 weeks 2 days 8 hours ago) and read 15356 times:

Quoting Stitch (Reply 102):
ETOPS-180 per the FAA and EASA TCDS.

Thanks, that's what I thought. So according to Wisdom's quote, the 787 is OK to fly without the APU battery (provided the VFSG systems operate normally), there is no reduction in its ETOPS ability.

That is how I am reading that. Am I incorrect?

Tugg



I don’t know that I am unafraid to be myself, but it is hard to be somebody else. -W. Shatner
User currently offlineStitch From United States of America, joined Jul 2005, 30978 posts, RR: 86
Reply 104, posted (1 year 6 months 3 weeks 2 days 8 hours ago) and read 15376 times:
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Quoting 7BOEING7 (Reply 101):
True, however that is written based on normal system configuration--not with a missing battery.

Well that it says "or" implies, at least to me, that the battery need not be installed to start the APU from either an engine generator or ground power.



Quoting tugger (Reply 103):
So according to Wisdom's quote, the 787 is OK to fly without the APU battery (provided the VFSG systems operate normally), there is no reduction in its ETOPS ability.

Correct. You can dispatch without an APU battery (or an inoperative APU battery) and operate up to 180 minutes from a diversion airport.


User currently offlinealfablue From Spain, joined Jan 2013, 43 posts, RR: 10
Reply 105, posted (1 year 6 months 3 weeks 2 days 7 hours ago) and read 15376 times:

Quoting Leahy:
“It’s unfortunate that these things happen but safety is the most important thing,” Leahy said. “When incidents happen like what they had with the battery we have to put the fleet on ground till you get it fixed. We’re talking about going back to a proven nickel cadmium battery technology that would be about 60 kilograms heavier. Why take a risk for 60 kilograms?”

This guy really grows on me -- Airbus is apparently looking into another assembly line for its 350 -- the discret period is over and Leahy makes it very clear -- keep it on the ground till you get it fixed! -- he even uses the s-word -- not good PR for Lithium today.

http://www.bloomberg.com/news/2013-0...s-787-woes-fail-to-dent-sales.html

alfaBlue

P.S.: you have to love following quote -- I think the talk about the exact battery function is very interesting but in the bigger picture if Boeing now gets comments like that:

Quote:

"Frankly, I think the odds of seeing the Dreamliner fly by April are about as good as those of seeing pigs fly. FAA administrator Michael Huerta hasn't even approved the proposal, never mind expressed confidence that Boeing can hold up its end of the deal. Japanese regulator Akihiro Ohta has pledged that certification will not be given simply for finding ways to compensate for overheating batteries; the root cause for the overheating must be found."

http://www.insidermonkey.com/blog/wi...y-ba-united-continental-ual-71961/

[Edited 2013-02-25 18:24:41]

User currently offlineStitch From United States of America, joined Jul 2005, 30978 posts, RR: 86
Reply 106, posted (1 year 6 months 3 weeks 2 days 7 hours ago) and read 15345 times:
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It's easy for JL to speak when the first production A350 is just starting to come together and they have the time to make the switch.

One wonders what his statements would be if he had a few score A350s in the air with Li-Ion batteries and was pumping out another 5-10 a month...


User currently offlinealfablue From Spain, joined Jan 2013, 43 posts, RR: 10
Reply 107, posted (1 year 6 months 3 weeks 2 days 7 hours ago) and read 15243 times:

Quoting Stitch (Reply 106):
One wonders what his statements would be if he had a few score A350s in the air with Li-Ion batteries and was pumping out another 5-10 a month...

You meant on the ground -- after all we talk about a grounding. Problems for the 350 might still arise so I find his statement quite bold as well but nevertheless I think now that UA and ANA announced further cancelations and the increasing pressure which will lead to increased scrutiny of a fix will keep the 787 grounded till after summer season - maybe even longer - I just don't see her fly anytime soon again.

alfaBlue


User currently offline7BOEING7 From United States of America, joined Oct 2012, 1591 posts, RR: 8
Reply 108, posted (1 year 6 months 3 weeks 2 days 6 hours ago) and read 15158 times:

Until we have the (M) & (O) procedures from the DDPG (or equivalent) we won't know for sure whether you are allowed to start the APU without the battery installed--looks like it may be the case but...


Interesting to note, the 777 MEL deals with the APU battery in 3 ways:

(O) May be "inoperative" provided APU is started before departure and is operated for the entire flight. (No ETOPS restriction so you're good for 380 minutes or whatever 777 max is now)

(O) May be "inoperative" provided:
a) Other procedures do not require the use of the APU, and
b) Flight remains within 180 minutes of a suitable airport

(M) (O) May be "inoperative removed" provided:
a) APU battery charger is deactivated
c) Other procedures do not require the use of the APU, and
b) Flight remains within 180 minutes of a suitable airport

So if you start before you go, you're good for ETOPS 180+--if not, whether or not the battery is installed you can't use the APU and you're good for ETOPS 180.


User currently offlinecornutt From United States of America, joined Jan 2013, 338 posts, RR: 1
Reply 109, posted (1 year 6 months 3 weeks 2 days 4 hours ago) and read 14949 times:

Quoting mjoelnir (Reply 90):
Lets say you lose the rectifiers/AC DC converters. 230V are still up 28V DC is down.

You seem to want to postulate incredible combinations of circumstances that only occur in bad novels. I think there are at least four sets of rectifiers and regulators. Being solid state, they are less likely to fail than the generators. I'll go ahead and make a bold prediction here: The last 787 will go to the scrapyard, 50 years from now, without this scenario ever happening.

Quoting Wisdom (Reply 91):
So again... sorry for being too careful. I'm sure that the B787 is so great that it would fly safely on only one of both wings.

Presumably you'd require that it have eight wings, in case some Irwin Allen fantasy takes out seven of them.


User currently offlinercair1 From United States of America, joined Oct 2009, 1320 posts, RR: 52
Reply 110, posted (1 year 6 months 3 weeks 2 days 4 hours ago) and read 14966 times:
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Quoting tugger (Reply 103):
That is how I am reading that. Am I incorrect?
Quoting alfablue (Reply 105):
This guy really grows on me -- Airbus is apparently looking into another assembly line for its 350 -- the discret period is over and Leahy makes it very clear -- keep it on the ground till you get it fixed! -- he even uses the s-word -- not good PR for Lithium today.

Give me a break - you think Airbus would be changing and Leahy crowing if the 787 had not had issues? No - they'd be moving ahead with Li-Ion batteries. This is just "plane" silly stuff and you know it.

Gee - If Li-Ion is so bad - then Airbus should be very grateful for Boeing showing them (Airbus) the right way - because they were obviously misguided.....NOT. (that is slang for being sarcastic).

Airbus has smart savy engineers and I'd be just as happy on a 350 with Li-Ion batteries as I would be on the 787. I don't, for a second, think Airbus has learned anything they did not already know about Li-Ion batteries from the 787 issues. Leahy is just blowing smoke and enjoying the misfortune of the competition. I expect that from him.

Hmmm - Are you really him incognito? (AlphaBlue = AB = AirBus.... or it could be Alton Brown. Are you a good cook?)   



rcair1
User currently offlinetrex8 From United States of America, joined Nov 2002, 4768 posts, RR: 14
Reply 111, posted (1 year 6 months 3 weeks 2 days 3 hours ago) and read 14897 times:

Quoting alfablue (Reply 105):
"Frankly, I think the odds of seeing the Dreamliner fly by April are about as good as those of seeing pigs fly. FAA administrator Michael Huerta hasn't even approved the proposal, never mind expressed confidence that Boeing can hold up its end of the deal. Japanese regulator Akihiro Ohta has pledged that certification will not be given simply for finding ways to compensate for overheating batteries; the root cause for the overheating must be found."

http://www.insidermonkey.com/blog/wi...y-ba-united-continental-ual-71961/

Guess ANA also agree

http://www.flightglobal.com/news/art...s-787-suspension-to-31-may-382683/


User currently offlinesankaps From United States of America, joined Jan 2008, 2255 posts, RR: 2
Reply 112, posted (1 year 6 months 3 weeks 2 days 1 hour ago) and read 14522 times:

Quoting Stitch (Reply 106):
It's easy for JL to speak when the first production A350 is just starting to come together and they have the time to make the switch.

One wonders what his statements would be if he had a few score A350s in the air with Li-Ion batteries and was pumping out another 5-10 a month...

Not sure I understand the point of your comment. If the problem was with the A350, I'm sure his reaction would be just the same, except it would be directed at Airbus, not Boeing. Airlines want aircraft to fly, not sit on the ground. The reality is today his 787s are sitting on the ground. It would be a bit silly for him to be castigating Airbus for that, wouldn't it? Don't customers have the right to voice their displeasure at some point if a product they buy does not perform as expected?


User currently offlinemjoelnir From Iceland, joined Feb 2013, 1449 posts, RR: 2
Reply 113, posted (1 year 6 months 3 weeks 1 day 23 hours ago) and read 14185 times:

Quoting Stitch (Reply 94):
If some event took out the Transformer Rectifier Unit and both Remote Power Distribution Units, I would not be surprised if it would affect the 28Vdc system to the point the batteries wouldn't be able to energize any of it.

Why go so far? If you loose the rectifiers you loose the 28V DC.


User currently offlinealfablue From Spain, joined Jan 2013, 43 posts, RR: 10
Reply 114, posted (1 year 6 months 3 weeks 1 day 22 hours ago) and read 14119 times:

Quoting rcair1 (Reply 110):
Give me a break - you think Airbus would be changing and Leahy crowing if the 787 had not had issues?

You misunderstood my comment - I was trying to express the oposite in a way - Leahy used in a few sentences following keywords: safety, incidents, risk and proven technology. He is playing the safety card and that is unheard of by manufacturers especially if they have their own product in the making which still has to prove itself. I don't expect the upper management to resort to this type of PR, but Leahy did - Either he had a glass of vine too much in Singapore or he is very bold and confident.

Quoting rcair1 (Reply 110):
Are you really him incognito? (AlphaBlue = AB = AirBus.... or it could be Alton Brown. Are you a good cook?)  

Oh no -- I assure you, that's a coincidence which was not intended -- I do however fly one of their products but thats the choice of my airline.

Bottom line is that Airbus was lucky this time trail blazing and its just ugly to play the safety card because for sure Boeing did not want this to happen neither (whether they risked it with insufficient quality control or whether those incidents were just bad luck is another story).

But as the Japanese regulator Akihiro Ohta says: Just curing the symptoms will not cut it for them -- To be honest I think EASA and FAA have a fairly good working relationship so I don't doubt the EU following the US authorities (if the FAA approves the fix) but will other regulators do the same? The Japanese want the root cause (not a better box) and the Chinese haven't even certified the jet yet. April seems just a very very short timeframe to fix the problems at hand.

alfaBlue

P.S.: Boeing had the Japanese market tightly in their hand. Asians are very discrete and especially in Japan they like to maintain their "faces" so the public talk about "JAL Chairman: 100% Reliance on Boeing 'Abnormal'" is a sign to me that they are actually fed up with the situation. Lets not forget Qatar's Al Baker which went mute recently but threatened before the grounding that the 787 better not have any more problems or he will cancel his order.

Some quotes of the JAL chairman:

"When I first became chairman of JAL in February 2010 I found out that 100 percent of Japan aircraft were made by Boeing - I felt that was abnormal."

"We should have been much, much more careful. The only consolation is that there has been no grave accident,"

"It is unacceptable to jump at every advance of new technological breakthrough. Technology used in aviation must be proficient, endurable and confirmed to be extremely reliable,"

http://www.cnbc.com/id/100488815




[Edited 2013-02-26 03:05:21]


[Edited 2013-02-26 03:09:33]

User currently offlinemjoelnir From Iceland, joined Feb 2013, 1449 posts, RR: 2
Reply 115, posted (1 year 6 months 3 weeks 1 day 22 hours ago) and read 14079 times:

Quoting cornutt (Reply 109):
You seem to want to postulate incredible combinations of circumstances that only occur in bad novels. I think there are at least four sets of rectifiers and regulators. Being solid state, they are less likely to fail than the generators. I'll go ahead and make a bold prediction here: The last 787 will go to the scrapyard, 50 years from now, without this scenario ever happening.

Most of the things thought about for preventing accidents are very unlikely.
A rectifier going down is not unusual, several is unlikely.
That is why you have several.
I hope that quite a few of the imagined faults will not happen during the lifetime of the B787,
that does not change that you have to think about them and calculate how often it happens.


The discussion is for what do you need the main battery and if it is it okay that the battery is less reliable than the types used in the older types of air plane, or if the regulators will demand a more reliable battery design apart from fixing the containment.

When the B 787 was certified, Boeing estimated the lifetime at about 3 to 4 years, the event of losing ONE cell in a runaway at 1 to ten millions flight hours and the two occurrences happening, the thermal runaway of the whole bater, were not planed for.
When ETOPS 180 was certified, it was calculated with a reliable main battery.

My opinion is: the better containment should get the B 787 flying again. To keep the ETOPS 180 rating without further changes to the battery regarding the reliability is another question.


User currently offlineWisdom From , joined Dec 1969, posts, RR:
Reply 116, posted (1 year 6 months 3 weeks 1 day 22 hours ago) and read 14024 times:

You gotta love Airliners.net
Since 9 threads the debate is on whether a stronger containment is sufficient for ETOPS 330.
Now suddenly, after some official publications were presented, the debate shifted to ETOPS 180 as the new standard.

Even for ETOPS 180, the assumption would be that the main battery can start the APU, hence you don't need the APU battery. That's on the assumption that the main battery is reliable.

Again the same here, an unreliable battery is the same as no battery, so no ETOPS.


User currently offlinerwessel From United States of America, joined Jan 2007, 2351 posts, RR: 2
Reply 117, posted (1 year 6 months 3 weeks 1 day 22 hours ago) and read 14002 times:
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Quoting Wisdom (Reply 82):
My opinion is that given failure rates of the B787 batteries, it would not be a responsible solution to just reinforce the containment.

Actually, if you see the containment reinforcement as a sufficient fix regardless of reliability of the battery, please explain to me why you would need a main battery at all and not remove it to get it over with?

This is getting silly. You need to main battery to power the electrical system during the recoveries from certain failures. Without knowing the various probabilities involved, we can't say for sure, but the requirement for the battery reliability (in the sense of being there to deliver electrical power), is that when combined with the probability of needing the battery for that role, the net reliability needs to meet some requirement. Now it may be that the battery currently has too low a reliability to meet that requirement, or perhaps there was sufficient margin in the design to allow even the flawed battery to provide a sufficiently reliable backup.

Quoting tugger (Reply 103):
Thanks, that's what I thought. So according to Wisdom's quote, the 787 is OK to fly without the APU battery (provided the VFSG systems operate normally), there is no reduction in its ETOPS ability.

That is how I am reading that. Am I incorrect?

Yes at least for now. There's not actually a link between the two, however. It's possible that the 787 will earn a longer ETOPS rating in the future, but the limit when dispatched with an MEL'd APU battery will remain at 180 minutes.


User currently offlinehivue From United States of America, joined Feb 2013, 1077 posts, RR: 0
Reply 118, posted (1 year 6 months 3 weeks 1 day 21 hours ago) and read 13823 times:

Quoting 7BOEING7 (Reply 95):
Yes the APU can be started in many different ways, however, nobody (with credentials) has confirmed whether the APU can be started without the APU battery in the airplane. Anybody with access to a 787 MEL/DDPG please speak up.
Quoting Stitch (Reply 99):
The 787 may also be dispatched with APU START SYS faults provided APU is started before departure and operated continuously throughout the flight.

See the Boeing video with Mike Sinnet posted in part 10 --

http://video.boeing.com/services/pla...0eUADvmgWcuM2F&bctid=2167891130001

Some posters dismissed it as PR fluff but I found it very informative.

At the 16:00 mark he talks about the APU battery. He implies that the APU battery is required for APU operation. He makes it sound like teh APU battery is the sole power source for the APU controller. He says:

"If you lose the APU battery in flight -- if it were to fail -- the only thing that happens is the APU safely shuts down."

He also says that "the airplane can be dispatched for revenue service with a failed APU battery. It doesn't provide a flight critical function..."

So it seems that the battery has the same criticality/backup level as the APU. My guess is that in circumstances where you can MEL the APU you can MEL the APU battery, and in circumstances where you can't MEL the APU you can't MEL the battery. (And dispatching with no APU battery means dispatching with no APU.)

[Edited 2013-02-26 05:37:59]

User currently offline7BOEING7 From United States of America, joined Oct 2012, 1591 posts, RR: 8
Reply 119, posted (1 year 6 months 3 weeks 1 day 17 hours ago) and read 13336 times:

Quoting hivue (Reply 118):

Some posters dismissed it as PR fluff but I found it very informative.

At the 16:00 mark he talks about the APU battery. He implies that the APU battery is required for APU operation. He makes it sound like teh APU battery is the sole power source for the APU controller. He says:

"If you lose the APU battery in flight -- if it were to fail -- the only thing that happens is the APU safely shuts down."

He also says that "the airplane can be dispatched for revenue service with a failed APU battery. It doesn't provide a flight critical function..."

So it seems that the battery has the same criticality/backup level as the APU. My guess is that in circumstances where you can MEL the APU you can MEL the APU battery, and in circumstances where you can't MEL the APU you can't MEL the battery. (And dispatching with no APU battery means dispatching with no APU.)

Thank you very much for providing an answer to the never ending question. I probably should have listened to Mike's presentation all the way through to begin with. His ZA002 presentation was also that of an engineer not a manager doing "PR fluff".


To sum it up, although the APU can be started from many different sources there are APU functions that can only be handled by the APU battery. If the battery is dead or not installed (swapped to the Main battery position) the APU cannot be started and the RAT becomes the third independent source allowing up to ETOPS 180 flights. For ETOPS 180+ you need an APU.

I imagine when the 787 achieves ETOPS 180+ the MEL will look similar to the 777 APU Battery MEL posted in Reply108 above.

THe Main battery is installed to provide a smooth transition to RAT power and provide braking capabilty after landing (if necessary).


User currently offlinercair1 From United States of America, joined Oct 2009, 1320 posts, RR: 52
Reply 120, posted (1 year 6 months 3 weeks 1 day 17 hours ago) and read 13245 times:
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Quoting alfablue (Reply 114):
You misunderstood my comment - I was trying to express the oposite in a way -

Yep - I sure did. Interesting how comments in a forum can be taken so differently than intended.

Quoting alfablue (Reply 114):
Bottom line is that Airbus was lucky this time trail blazing and its just ugly to play the safety card because for sure Boeing did not want this to happen neither

  
I might say - maybe Boeing will be lucky next time - but honestly, I'd prefer neither company have to deal with issues like this. Of course, that is unrealistic and the net result will likely be better aircraft (not always tho)

Quoting 7BOEING7 (Reply 119):
Thank you very much for providing an answer to the never ending question. I probably should have listened to Mike's presentation all the way through to begin with. His ZA002 presentation was also that of an engineer not a manager doing "PR fluff".

I'm sorry - I watched the full presentation too. However, I do not think this is an authoritative answer. I don't question his technical ability or intent - just I think it is quite possible he misspoke. As as engineer whose job was to represent technology to technical press world wide for many years - I can sympathize. More than once a simple error crept into my presentations and I did not catch it. That was particularly the case when talking about a part of the system I was familiar with, but not intimately involved in the design of. For that reason, and because there are other tidbits of evidence, I'm not ready to conclude that the APU battery is required for APU operations. That seems like an arbitrary decision - looking at the Boeing supplied diagrams, that is not required. It would be very easy to isolate the APU battery from the APU - just as it would need to be isolated from the main buss's (the APU battery). There are also clear connections from the main busses to the APU S/G's (I hate that - they are really alternators, not generators....) Why would you make that decision while at the same time making the decision to design the a/c so the APU battery could be used to replace the main battery. Why give up a system like the APU? It doesn't make sense to me as an electrical engineer. Now - that is a gut feel - not data - and I could be wrong. However, a single statement in a presentation to the press, no matter how well intentioned does not read as authoritative. What it would be nice to see is the actual MEL.



rcair1
User currently offlinefrmrCapCadet From United States of America, joined May 2008, 1718 posts, RR: 1
Reply 121, posted (1 year 6 months 3 weeks 1 day 17 hours ago) and read 13187 times:

A little off topic, but I don't think it has been specifically mentioned.

Airline manufacturers and regulatory agencies are unique (or bad grammar very unique). Their cooperation over the last century has functioned to make flying better and safer year after year. And the close cooperation was built in very early. Read Sutter's book, Boeing helped write the original specs for safe jetliners - and it was not done under the table or in smoke filled rooms. It was done openly and by engineers.

The drug industry, as well as foods, hospitals, automobiles, financial spend millions to deny, lie, and get by. Just off the top of my head I could write pages about the dangers and short cuts that endanger us daily in these fields.

The air industry is the shining exception. From the rudest FA to the greenest pilot, the reddest necked mechanic, and the striking ATCs - all of them bring a committment to air safety. I have never worried and neither do any of us as we get on a plane in most of the world. We know there are a few exceptions.



Buffet: the airline business...has eaten up capital...like..no other (business)
User currently offlinehivue From United States of America, joined Feb 2013, 1077 posts, RR: 0
Reply 122, posted (1 year 6 months 3 weeks 1 day 17 hours ago) and read 13189 times:

Quoting rcair1 (Reply 120):
just I think it is quite possible he misspoke

You could very well be correct. However, his statement in the video that if the APU battery goes belly up in flight and the APU is running the APU shuts down seems pretty clear and straightforward to me.

[Edited 2013-02-26 08:30:11]

[Edited 2013-02-26 08:32:05]

User currently offline7BOEING7 From United States of America, joined Oct 2012, 1591 posts, RR: 8
Reply 123, posted (1 year 6 months 3 weeks 1 day 17 hours ago) and read 13091 times:

Quoting frmrCapCadet (Reply 121):
What it would be nice to see is the actual MEL.

We do have the MEL. It's above in Reply 96 from WISDOM who also provided us with the FAA website which gets you to to all the MELS. Unfortunately we don't as of yet have the DDPG (Dispatch Deviation Procedures Guide) which would tell us what (O) Operating and (M) Maintenance procedures are necessary to dispatch with the battery dead/missing.

The 777 MEL above in Reply 108 gives an indication that with either the battery dead or missing the APU is unavailable. Most Boeing airplanes have APU functions that are only available from the APU battery bus, i.e. no APU battery--no APU.

[Edited 2013-02-26 08:46:41]

Sorry, wrong person right quote????


[Edited 2013-02-26 08:57:16]

User currently offlinetarmacphotos From United States of America, joined Jul 2007, 383 posts, RR: 2
Reply 124, posted (1 year 6 months 3 weeks 1 day 13 hours ago) and read 12565 times:

I just saw this on Flightaware

http://flightaware.com/live/flight/U...2/history/20130226/1915Z/KLAX/RJAA

Is this a glitch or are they flying?


User currently offlineStitch From United States of America, joined Jul 2005, 30978 posts, RR: 86
Reply 125, posted (1 year 6 months 3 weeks 1 day 13 hours ago) and read 12478 times:
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Quoting tarmacphotos (Reply 124):
Is this a glitch or are they flying?

Glitch. It's operated with a 777-200ER.

[Edited 2013-02-26 12:30:50]

User currently offlinerotating14 From United States of America, joined Jan 2012, 659 posts, RR: 0
Reply 126, posted (1 year 6 months 3 weeks 1 day 10 hours ago) and read 12071 times:

Hello all,

So I arrived home for from work and caught the tail end of the CNBC show Fast Money, which highlighted Boeing for a bit but what caught my eye was the breaking news bulletin about the FAA probably allowing 787 flights by next week. Anyone else catch this also?


User currently offlineStitch From United States of America, joined Jul 2005, 30978 posts, RR: 86
Reply 127, posted (1 year 6 months 3 weeks 1 day 10 hours ago) and read 12322 times:
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Quoting rotating14 (Reply 126):
So I arrived home for from work and caught the tail end of the CNBC show Fast Money, which highlighted Boeing for a bit but what caught my eye was the breaking news bulletin about the FAA probably allowing 787 flights by next week. Anyone else catch this also?

Cowen & Co. analyst Cai von Rumohr posted a research note today stating he thought the FAA might respond to Boeing's proposed fix next week, but he also noted he did not expect the grounding AD to be lifted before mid-year. His view is the FAA would still require additional changes after they lift the grounding.

http://www.suntimes.com/business/184...er-solution-next-week-analyst.html


User currently offlinerotating14 From United States of America, joined Jan 2012, 659 posts, RR: 0
Reply 128, posted (1 year 6 months 3 weeks 1 day 10 hours ago) and read 12306 times:

Update --> So it's not allowing them but giving Boeing the yay or nay for the proposed fix.


http://www.suntimes.com/business/184...er-solution-next-week-analyst.html


User currently offlinePHX787 From Japan, joined Mar 2012, 7560 posts, RR: 18
Reply 129, posted (1 year 6 months 3 weeks 1 day 10 hours ago) and read 12268 times:

Quoting rotating14 (Reply 128):
Update --> So it's not allowing them but giving Boeing the yay or nay for the proposed fix.

So this pretty much implies that the FAA is going to review the proposed fix, give them the yay/nay on doing the fix, and subsequently allowing them to run tests to prove this fix is safe, which is per the wording of the A.D. Once they run these tests and fixes and have the other airlines do these fixes as well, we can see the A.D. lifted, right?



次は、渋谷、渋谷。出口は、右側です。電車とホームの間は広く開いておりますので、足元に注意下さい。
User currently offlineServantLeader From United States of America, joined Jan 2013, 69 posts, RR: 0
Reply 130, posted (1 year 6 months 3 weeks 1 day 9 hours ago) and read 12133 times:

Quoting rcair1 (Reply 62):
Engineering responds to science, PR to emotion.

And science is inexact and

Quoting hivue (Reply 118):
Some posters dismissed it as PR fluff but I found it very informative.

IMO it is the "PR stuff" that will decide if and when the 787 goes back into revenue service. The hard engineering / science work has reached a point of diminished returns -- barring a breakthough on either of those fronts in the next week the FAA will decide whether better containment and/or venting of a battery system known to self-ignite equates to 1000% safe -- color me sketpitcal.

[Edited 2013-02-26 16:00:43]

User currently offlineWisdom From , joined Dec 1969, posts, RR:
Reply 131, posted (1 year 6 months 3 weeks 1 day 9 hours ago) and read 12060 times:

Quoting mjoelnir (Reply 115):
My opinion is: the better containment should get the B 787 flying again. To keep the ETOPS 180 rating without further changes to the battery regarding the reliability is another question.

This is my view as well.
Better containment should provide sufficient safeguard for normal operations without ETOPS, under certain conditions:

-The containment must block the emission of odd-smelling vapors and carry temperature sensors.
-Double or triple EWIS inspections during all heavy maintenance inspections, preferably right before closing up.
-APU serviceable before any flight
-Max. Diversion time 60 minutes
-Additional training for flight crews regarding the electrical system, including multiple failures simulation
-Have the captain carry a back-up communication and navigation kit, consisting of a 2-way VHF radio (I've seen a lot of airline pilots carry one) and an aviation GPS, both rechargeable and charged to last 60 minutes.


User currently offlinekanban From United States of America, joined Jan 2008, 3547 posts, RR: 26
Reply 132, posted (1 year 6 months 3 weeks 1 day 9 hours ago) and read 11998 times:
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Quoting Wisdom (Reply 131):
under certain conditions:

maybe a slight over kill.. one the passenger next to you may smell worse than these fumes BTW 10 flights in the last 8 days had smoke or odors ...

and 5 had engine failures..

it is beyond me why you want extra ordinary limitations on this aircraft and are content to all others fly.. ( I believe there was one that had navigational discrepancies between two computers)..

there is not one model out there that doesn't have a system failure or perceived failure occasionally, in fact here were 40 reportable events not including runway excursions last week.

so please stop the nonsense.


User currently offline7BOEING7 From United States of America, joined Oct 2012, 1591 posts, RR: 8
Reply 133, posted (1 year 6 months 3 weeks 1 day 8 hours ago) and read 11929 times:

Quoting kanban (Reply 132):
so please stop the nonsense.



I agree. If the FAA signs off on the present Boeing fix I think ETOPS 180 will not be greatly affected. Possibly adding a working APU as an initial requirement. ETOPS 180+ hasn't been blessed yet and it may be harder to get it as soon as was initially planned.


User currently offlineNAV20 From Australia, joined Nov 2003, 9909 posts, RR: 35
Reply 134, posted (1 year 6 months 3 weeks 1 day 6 hours ago) and read 11677 times:

Isn't 'von Rumohr' a marvellous name for an analyst?  

Hopefully we are approaching a 'turning-point.' So far, though, Boeing are still at the laboratory-testing stage, and the FAA are 'playing a bit hard to get' on the issue of flight tests:-

"Boeing is conducting laboratory tests on its proposed fixes for the lithium-ion batteries on its new 787 jets, and federal regulators said Tuesday that they would need to see the results before deciding whether to allow flight tests.

"The Federal Aviation Administration is conducting its own evaluation of the changes, which are meant to keep the batteries from catching fire or emitting smoke, as occurred on two flights in January.

"Industry and federal officials said the agency had rejected a request from Boeing to set a date to begin checking the solutions on flights by Boeing’s test aircraft.

"Laura J. Brown, an agency spokeswoman, said Tuesday that “reports that we are close to approving test flights are completely inaccurate.”


http://www.nytimes.com/2013/02/27/bu...t-boeing-battery-results.html?_r=0



"Once you have flown, you will walk the earth with your eyes turned skywards.." - Leonardo da Vinci
User currently offlinehivue From United States of America, joined Feb 2013, 1077 posts, RR: 0
Reply 135, posted (1 year 6 months 3 weeks 18 hours ago) and read 10843 times:

Quoting NAV20 (Reply 134):
Isn't 'von Rumohr' a marvellous name for an analyst?

  

Might be a good one for some a.net posters too.  


User currently offlineWisdom From , joined Dec 1969, posts, RR:
Reply 136, posted (1 year 6 months 3 weeks 17 hours ago) and read 10633 times:

Quoting kanban (Reply 132):
it is beyond me why you want extra ordinary limitations on this aircraft and are content to all others fly.. ( I believe there was one that had navigational discrepancies between two computers)..

I'm a rational guy. I've seen airplanes wide open and have seen things only a few other guys in this world have seen.

Do I have an issue with the B787? Yes I do. My issue is that the B787 design was marketing driven as opposed to bluntly designing a marvelous airplane.

First issue, CFRP all over. Will it really last longer? I don't think so. Since 90 years aircraft were built out of aluminium and steel. CFRP has different load patterns and is very unpredictable (cfr John Leahy and the A380 wing cracks). Titanium on the other hand is very similar to aluminum and steel, so I don't mind its use at all.

Second issue, all-electric. All-electric is not a new concept for an airplane. In fact, it was contemplated since the early days of the jet era, the B707 and DC-8. These aircraft required a separate turbocompressor to get ram air compressed, so the question was whether they will be powered electrically and placed next to the Air cycling machine with larger generators on the engines or will they be placed directly on the engines and run ducts from there, independently from the electrics.
Both designs went for redundancy, ie "bleed air" (technically it's engine-power generated compressed ram air) the idea being that as long as the engines were running, there would be need for pressurisation. The logic is right and obvious, if you have no engines, you can't sustain flight at altitude so you don't need pressurisation.
As long as engines are running and you're flying up there, you might need pressurisation. Makes sense no?

The issue Boeing created by going electric, is to remove this redundancy, meaning that it's possible now that while the engines are running fine, the aircraft may not maintain pressurisation when a major electrical failure strikes.

Quoting kanban (Reply 132):

Quoting Wisdom (Reply 131):
under certain conditions:

maybe a slight over kill.. one the passenger next to you may smell worse than these fumes BTW 10 flights in the last 8 days had smoke or odors ...

No overkill, aviation is about better safe than sorry.
Fumes from batteries are very obnoxious, they can start the development of cancer cells if exposed at high concentration for prolonged times.



Do I have an issue with li-ion technology? No, frankly no.
I supply thingies that are centered on li-ion technology and they are just marvelous and uberly reliable batteries.
Thanks to Boeing however, I will be spending a lot more money to get my li-ions shipped, as they will become CAO (cargo aircraft only), treated as dangerous goods requiring dangerous goods inspection and freight companies will charge more for all the extra work and risk involved.

Thank you Boeing, your marketing success is going to hit companies worldwide with millions of added logistics costs, trickling down to consumers as increased purchase cost of goods.
Do you guys realise the impact this is going to have on prices you pay for computers, cell phones, etc...?


User currently offlinehivue From United States of America, joined Feb 2013, 1077 posts, RR: 0
Reply 137, posted (1 year 6 months 3 weeks 16 hours ago) and read 10525 times:

Quoting Wisdom (Reply 136):
The issue Boeing created by going electric, is to remove this redundancy, meaning that it's possible now that while the engines are running fine, the aircraft may not maintain pressurisation when a major electrical failure strikes

The implication here is that bleed air will not fail independently of engine failure. I am not involved in aviation but I suspect this is not the case. There have to be valves and things involved that can fail. Of course, bleed air systems will have backups but so will electrical systems. I'm not sure any redundancy has been lost.

Quoting Wisdom (Reply 136):
they will become CAO (cargo aircraft only), treated as dangerous goods requiring dangerous goods inspection

Maybe this is a good thing if the 787 Li-Ion batteries are as dangerous as you and many others seem to imply. Perhaps Boeing has inadvertently done us all a favor?


User currently offlinekanban From United States of America, joined Jan 2008, 3547 posts, RR: 26
Reply 138, posted (1 year 6 months 3 weeks 16 hours ago) and read 10524 times:
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Well Wisdom, I spent 35 years in the industry and have seen many dramatic changes and saw and understood many more things in the last 50 years than I saw or comprehended in my first quarter century... We have been using composites of various types for years in both commercial and military applications.. nay sayers don't get it.. however if you want to start separate thread.. go ahead and get flamed.

the issue here is three out of 300 or so batteries.. two failed, one bulged.. hardly the result of an all electric environment..

Quoting Wisdom (Reply 136):
Thanks to Boeing however, I will be spending a lot more money

The cause is the battery chemistry not Boeing..

Quoting Wisdom (Reply 136):
Thank you Boeing,

ditto..

Why not blame Boeing for horse meat in you meatballs?

Quoting Wisdom (Reply 136):
Fumes from batteries are very obnoxious, they can start the development of cancer cells if exposed at high concentration for prolonged times.

smoke and odors in the plane (many of which if inhaled in copious quantities will have an effect on cells and life itself) are common and are already dealt with quickly..


User currently offlinemjoelnir From Iceland, joined Feb 2013, 1449 posts, RR: 2
Reply 139, posted (1 year 6 months 3 weeks 14 hours ago) and read 10123 times:

Quoting rcair1 (Reply 93):
Quoting kanban (Reply 138):
the issue here is three out of 300 or so batteries.. two failed, one bulged.. hardly the result of an all electric environment..

3 out of 100 batteries, 50 frames times 2 batteries each.
In the ANA bird the second battery was bulging, that is 2 batteries in one air plane.
And Boeing had a reliability issue with the batteries anyway.
All the exchanged batteries, the most common cause was discharged to far, but not the only one.
No battery longer in use than a year.
All on a battery with a projected lifespan of three to four years.

Quoting kanban (Reply 138):
The cause is the battery chemistry not Boeing..

Boeing only chose those batteries.

Quoting kanban (Reply 138):
ditto..

Why not blame Boeing for horse meat in you meatballs?

Boeing did not order the meatballs, or did they?


User currently offlineSassiciai From UK - Scotland, joined Jan 2013, 346 posts, RR: 0
Reply 140, posted (1 year 6 months 3 weeks 13 hours ago) and read 9992 times:

11 threads already, and the speculation is the same now as in post 2 of the first thread!

I cant contribute to all this speculative stuff about battery technology that has kept everyone busy (???) for 11 threads. But I'm keen to discuss the impact of this fleet-wide grounding on the general area of airlines' operations!

Already 50 delivered aircraft are grounded, and another "X" which should have been delived by end-February 2013 are also grounded. If there is no releif on the horizon by mid-year, there's another 20 - 40 planes "not in service". Then it goes on, month by month!

Already we know that LOT, ANA, UA, etc are amending their ops planning to have zero availability for 787 for some time.

How are the existing customer airlines coping with this (schedule reduction, cancel new routes, etc), and what are the knock-on effects on near-term customers who have yet to receive their first, but now dont know when they will?


User currently offlinehivue From United States of America, joined Feb 2013, 1077 posts, RR: 0
Reply 141, posted (1 year 6 months 3 weeks 13 hours ago) and read 9997 times:

Quoting mjoelnir (Reply 139):
No battery longer in use than a year.
All on a battery with a projected lifespan of three to four years.

IIRC from previous posts in this thread, it's likely that few/none of the swapped out batteries went in the trash. Mx checked them, fixed ones that needed fixing, recharged them and they could then go back in service. They were swapped out because an over-discharged battery cannot be charged while in the plane (or at leat not without a lot of hassle).


User currently offlineStitch From United States of America, joined Jul 2005, 30978 posts, RR: 86
Reply 142, posted (1 year 6 months 3 weeks 13 hours ago) and read 9994 times:
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Quoting Sassiciai (Reply 140):
How are the existing customer airlines coping with this (schedule reduction, cancel new routes, etc), and what are the knock-on effects on near-term customers who have yet to receive their first, but now dont know when they will?

They're canceling services, reducing frequencies, subbing other equipment, extending existing leases and other options.

The next batch of new customers are the Chinese, but China was dragging it's feet on certifying the plane even before the grounding so the effect on them is probably the least pronounced as they were not in a position to take delivery, anyway.


User currently offlinesankaps From United States of America, joined Jan 2008, 2255 posts, RR: 2
Reply 143, posted (1 year 6 months 3 weeks 13 hours ago) and read 9977 times:

Quoting mjoelnir (Reply 139):
Boeing only chose those batteries.

Not just chose the battery, but selected the underlying technology, specified the specs, and pretty much self-certified them. Only thing they did not do is manufacture the batteries.

So for anyone (especially a self-proclaimed industry insider) to imply that Boeing somehow does not have any responsibility for the battery debacle, only the battery maker does, especially since it is not yet known whether it is the battery or the surrounding systems that are causing the problems, is highly unexpected and irresponsible.

[Edited 2013-02-27 12:25:49]

User currently offlineSassiciai From UK - Scotland, joined Jan 2013, 346 posts, RR: 0
Reply 144, posted (1 year 6 months 3 weeks 13 hours ago) and read 9945 times:

The existing customers are facing what one could call "tactical"" problems - they have timetables, bookings, and even, in some cases, "787-glory" programmes (e.g. ANA and LOT, to name but 2). So yes, they are in the process of ensuring short term lift, by renewing leases and prolonging service life of existing frames, to address actual ops problems. ANA having 17 787s grounded must be a bit of a scheduling problem!

How are future customer airlines reacting/planning to this situation? All are impacted, for sure, so how are they accomodating this?


User currently offlineServantLeader From United States of America, joined Jan 2013, 69 posts, RR: 0
Reply 145, posted (1 year 6 months 3 weeks 13 hours ago) and read 9910 times:

Quoting Sassiciai (Reply 144):
How are future customer airlines reacting/planning to this situation? All are impacted, for sure, so how are they accomodating this?

In a word, not very well thank you very much. This thread gets deep into the physics and chemistry of the Li-ion battery system and its function aboard the 787, which is all well and good, but that means little to customers who had to endure 3+ years of delays and now a global grounding with no end in sight. This is going to leave a mark.

[Edited 2013-02-27 12:33:33]

User currently offlinejumpjets From United Kingdom, joined Apr 2012, 818 posts, RR: 0
Reply 146, posted (1 year 6 months 3 weeks 13 hours ago) and read 9844 times:

Quoting Stitch (Reply 142):
The next batch of new customers are the Chinese

Not to mention Thompson Airlines/TUI in the UK who have been heavily promoting their new super 787 services from this May and BA who presumably, before this issue, were about to announce their routes for the first of their planes due to arrive from mid year onwards.


User currently offlineSassiciai From UK - Scotland, joined Jan 2013, 346 posts, RR: 0
Reply 147, posted (1 year 6 months 3 weeks 13 hours ago) and read 9835 times:

Quoting ServantLeader (Reply 145):
In a word, not very well thank you very much. This thread gets deep into the physics and chemistry of the Li-ion battery system and its function aboard the 787, which is all well and good, but that means little to customers who had to endure 3+ years of delays and now a global grounding with no end in sight. This is going to leave a mark.

Thanks! it's exactly that I'm a bit distressed at 11 threads about batteries and chemistry, with little discussion on the obvious impact on airline operations.

There is a technical issue of the batteries. Let technicinas resolve that (or change the specifications), and lets all relax on this A-forum on Airliners. Please open a new thread on the "Chemistry in aviation" area!

There are 50 787 in customer hands, and another 750+ in progress. With no plan for the lifting of the grounding, how are the customers of these 750+ preparing/reacting?

Even airline execs are not well clued up on battery technology; nor should they be! Are there any "Plan B"s out there being drawn up? If not, why not?


User currently offlineZKCIF From Lithuania, joined Oct 2010, 297 posts, RR: 0
Reply 148, posted (1 year 6 months 3 weeks 12 hours ago) and read 9666 times:

Quoting Sassiciai (Reply 147):
another 750+ in progress. With no plan for the lifting of the grounding, how are the customers of these 750+ preparing/reacting?

This concerns those who expect to get something from the first 100 from these 750. for others, the dates are not specified so precisely. Manufacturing is still taking place, so (provided the grounding does not exceed some 6 months) Boeing will have a flurry of deliveries after grounding has ended.

The REAL winners are lessors whose 767s instead of gracing mohaves and maranas are designing contrails being leased at highish prices


User currently offlinemjoelnir From Iceland, joined Feb 2013, 1449 posts, RR: 2
Reply 149, posted (1 year 6 months 3 weeks 11 hours ago) and read 9502 times:

Quoting hivue (Reply 141):
IIRC from previous posts in this thread, it's likely that few/none of the swapped out batteries went in the trash. Mx checked them, fixed ones that needed fixing, recharged them and they could then go back in service. They were swapped out because an over-discharged battery cannot be charged while in the plane (or at leat not without a lot of hassle).


Completely discharged was one of several reasons, the other (s) not defined.
So how many were bad and not just discharged. 1, 2, 10, 20?
And for what reason did they go bad?
Any information that there were more bulging batteries?

My laptop warns me and shuts down.
The acceptance that the system, while supervising the batteries, allows them to be completely discharged in non emergency situations, is at least strange.

[Edited 2013-02-27 14:07:32]

User currently offlinehivue From United States of America, joined Feb 2013, 1077 posts, RR: 0
Reply 150, posted (1 year 6 months 3 weeks 11 hours ago) and read 9471 times:

Quoting Sassiciai (Reply 147):
There are 50 787 in customer hands, and another 750+ in progress.

50 in customer hands (or, rather, sitting on their ramps), yes, but not 750+ "in progress" -- most of those are just line items in purchase contracts (by the time Boeng starts putting together #750 this will probably all be a very dim memory).

Does anyone have decent numbers for how many actual deliveries and how many airline EIS's have been delayed to-date as a result of the AD?


User currently offlinercair1 From United States of America, joined Oct 2009, 1320 posts, RR: 52
Reply 151, posted (1 year 6 months 3 weeks 11 hours ago) and read 9472 times:
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CUSTOMER SERVICE & SUPPORT

Quoting ServantLeader (Reply 130):
And science is inexact

Huh? Are there things in physics and science we don't understand? Yes. Are there tradeoffs between 'perfect' science and estimates? Yes?
But I'm not going along with a blanket statement that science is inexact.

Quoting Wisdom (Reply 136):
Thanks to Boeing however, I will be spending a lot more money to get my li-ions shipped, as they will

Li-Ion batteries have been on the hot list for shipping, and with increased intensity, for some time. Many think that shipment if Li-Ion batteries by aircraft should be cargo only - and that it should be highly regulated.
BUT - there is a major difference between shipping Li-Ion batteries and having one in a controlled, monitored and contained environment.
Don't lay your woes at shipping Li-Ion batteries at Boeing's feet - that is just plan silly. It is hardly the case that all the shipping regulators suddenly went "Hmmm - Boeing had problems with 2 Li-Ion Batteries. Gee, I never knew there was an issue with shipping Li-Ion batteries. Maybe we'd better change all the regulations."

Quoting hivue (Reply 137):
The implication here is that bleed air will not fail independently of engine failure. I am not involved in aviation but I suspect this is not the case.

Of course bleed air can fail. It can also pose fire hazards and all sorts of things.
Frankly - I'd rather run wires than ducts. It is a lot easier, smaller, and probably safer.



rcair1
User currently offlineAesma From France, joined Nov 2009, 6651 posts, RR: 11
Reply 152, posted (1 year 6 months 3 weeks 11 hours ago) and read 9627 times:

Quoting Sassiciai (Reply 147):
Thanks! it's exactly that I'm a bit distressed at 11 threads about batteries and chemistry, with little discussion on the obvious impact on airline operations

I thought the Tech/Ops thread would be discussing these issues but apparently it's similar to this one : Tech/Ops Discussion Of The 787 Grounding (by CM Jan 22 2013 in Tech Ops)



New Technology is the name we give to stuff that doesn't work yet. Douglas Adams
User currently offlinehivue From United States of America, joined Feb 2013, 1077 posts, RR: 0
Reply 153, posted (1 year 6 months 3 weeks 11 hours ago) and read 9617 times:

Quoting mjoelnir (Reply 149):
Completely discharged was one of several reasons, the other (s) not defined.
So how many were bad and not just discharged. 1, 2, 10, 20?

I agree. That would be very interesting to know. And if several actually were bad very early in their expected lifetimes rather than just in need of a re-charge, why didn't someone raise a red flag before 2 fried within 8 days?


User currently offlineWisdom From , joined Dec 1969, posts, RR:
Reply 154, posted (1 year 6 months 3 weeks 10 hours ago) and read 9509 times:

Quoting rcair1 (Reply 151):
Li-Ion batteries have been on the hot list for shipping, and with increased intensity, for some time. Many think that shipment if Li-Ion batteries by aircraft should be cargo only - and that it should be highly regulated.
BUT - there is a major difference between shipping Li-Ion batteries and having one in a controlled, monitored and contained environment.
Don't lay your woes at shipping Li-Ion batteries at Boeing's feet - that is just plan silly. It is hardly the case that all the shipping regulators suddenly went "Hmmm - Boeing had problems with 2 Li-Ion Batteries. Gee, I never knew there was an issue with shipping Li-Ion batteries. Maybe we'd better change all the regulations."

Yes it's Boeing's fault.
ICAO said it in clear words:

ICAO Decision Temporarily Restricts Carriage of Lithium Ion Aircraft Batteries as Cargo on Passenger Aircraft
COM 3/13
​MONTRÉAL, 13 February 2013 – Pending the outcomes of investigations now being carried out in the United States and Japan, the President of the Council of the International Civil Aviation Organization (ICAO) has provisionally approved an interim amendment that will prohibit the carriage of lithium ion aircraft batteries as cargo on passenger planes. Final approval of the amendment from the ICAO Council is expected when it returns to Session later this month.
http://www.icao.int/Newsroom/Pages/I...s-cargo-on-passenger-aircraft.aspx


ICAO is considering to make this permanent and my guts tell me they will, together with IATA.
Li-ion batteries that aren't connected to a circuit and shipped as they are supposed to be, are safe as long as there's nothing catching fire in the same hold as they are loaded. Stuff like paper and cardboard boxes are also flammable, regardless of their content.

There are always amateurs from some shady factories in China who ship them like they're sardine boxes.

Quoting kanban (Reply 138):
We have been using composites of various types for years in both commercial and military applications.. nay sayers don't get it.. however if you want to start separate thread.. go ahead and get flamed.

Like I said in many other threads, name me one aircraft that is all composite and has more than 10.000 cycles on it. Reinforced concrete is a composite too. I've seen applications with Tungsten, Kevlar, Graphite, glass fiber and so on. The only thing I can tell you for sure about all of them is that each of these materials has a lower rigidity and combined, they are stronger.
However, when one link in the chain breaks, the material loses all rigidity.

I do believe that for the main loads they are designed to carry, they will showcase higher fatigue resistance and better load bearing. However for the other loads, such as vibrations, shear, thermal, friction and non-main loads, they will have worse properties than aluminum and that's what you will only find out after 10.000 cycles/20.000 hours, mark my words.
Add the fact that even the main loads will be highly doubtful. Proof is that regardless of all the design work that went into it and all the know-how, the B787 failed its first wing breaking test by rather embarassing margins. What's going to happen to the fuselage that undergoes stress in all directions in very unpredictable pattterns?
Then everybody talks about the floor beams or the fan blades on the B777 as if those structures undergo the same stress as a complete fuselage or a wing.



If you want to discuss impact on airlines, start your own thread instead of forcing us out.
What's the impact? Plain simple, everyone is unhappy, everyone is scrambling to find interrim lift, short-term lease rates are higher, customers are keeping quiet while Boeing sorts its mess out but they will rumble later on, get some discounts on future deliveries and life goes on.
What more is there to say?


User currently offlineAeroWesty From United States of America, joined Oct 2004, 20632 posts, RR: 62
Reply 155, posted (1 year 6 months 3 weeks 10 hours ago) and read 9481 times:

.

Quoting Sassiciai (Reply 147):
Thanks! it's exactly that I'm a bit distressed at 11 threads about batteries and chemistry, with little discussion on the obvious impact on airline operations.

What is it that you want to do? Keep a running list of flights that have been either cancelled or are on hold due to the groundings? That might be an unwieldy data set to manage in an open forum.

For instance, UA is keeping their 5 remaining 762s in the fleet that they were expecting to get rid of. 4 are running international routes temporarily, and one is running domestic ops, to cover for where other equipment has had to be moved around. UA has also delayed the refurbishment of some aircraft, as they can't be taken out of service while the 787s remain on the ground.

I'm sure you could build a table of which flights have been substituted by what equipment on the affected airlines, but it's probably too fluid of a situation for some to make it into a static set of data. LO is probably the easiest one to document—they were expecting to ground their whole 767 fleet as 787s came in.



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