NathanH
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RE: FAA Grounds 787 Part 4

Tue Jan 22, 2013 11:33 pm

Quoting alfablue (Reply 151):
I can not believe you asked that! Thats the worst I have read here today I think

The statement was made that technological advancement shouldn't risk life. All that was being said was that in the course of human history, that has been in incorrect statement.

Frankly, your hysteria on this is getting a little much. Some of us are trying to follow this and get reasoned insight into the technological issues at hand, and then you come along making hyperbolic statements and parading rumors as fact.
 
alfablue
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RE: FAA Grounds 787 Part 4

Tue Jan 22, 2013 11:46 pm

Quoting NathanH (Reply 153):
Frankly, your hysteria on this is getting a little much. Some of us are trying to follow this and get reasoned insight into the technological issues at hand, and then you come along making hyperbolic statements and parading rumors as fact.

The news overnight seems to have become increasingly troubling for Boeing, as investigations into the 787′s problems fan out in all directions.

http://www.forbes.com/sites/eamonnfi...gs-787-crisis-important-new-links/

Mary Schiavo says quick fix looks unlikely as regulators appear split on what caused battery defects in Dreamliner 787s

http://www.guardian.co.uk/business/2...0-dreamliner-fire-split-regulators

well - call me hysteric if you like - i heard worse in my life  

Read the facts than on the links.

AlfaBlue
 
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Stitch
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RE: FAA Grounds 787 Part 4

Tue Jan 22, 2013 11:59 pm

Quoting liquidair (Reply 152):
I understand the A350 may share this technology, but frankly, they're not in service yet, and certainly haven't caught fire with passengers on board, hence my citing the comparison as irrelevant.

A significant plurality of the 1000+ posts have been arguing that Lithium-Ion batteries are inherently dangerous and their installation aboard a commercial airliner will eventually result in a catastrophic event. Under that line of reasoning, that the A350 has not yet encountered a battery fire or leak of electrolytes is what is irrelevant, as it will assuredly happen at some point in the model's service life because it has Lithium-Ion batteries.
 
RNAVFL350
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RE: FAA Grounds 787 Part 4

Wed Jan 23, 2013 12:04 am

Quoting ComeAndGo (Reply 139):
No, you have a potential source of fire and no extinguishers. that's not the same.

The potential source of fire is installed within a containment (vented so as to not produce a bomb) which seems to have worked as per its design. Others here have already discussed the leaking battery material/electorlytes from the containment in earlier posts, and the fact that this EE bay was designed with the possibility of leaking fluids due to the PECS(liquid cooling) system that cools the panels/electronics.

I am pretty sure that the fuel carried on the airplane is also a potential source of fire with no extinguishers as well. Or less dramatic, the coffee makers, though there may be extinguishers for this.
 
UALWN
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RE: FAA Grounds 787 Part 4

Wed Jan 23, 2013 12:17 am

Quoting Cubsrule (Reply 124):
Do you believe that the 380 should be grounded until the lithium ion batteries are removed from its emergency lighting system?

As far as I know, there has not been any fire attributed to the Li ion batteries in the almost 100 A380s that are flying since first entering service over 5 years ago. The situation regarding the 787 is very different.
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RNAVFL350
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RE: FAA Grounds 787 Part 4

Wed Jan 23, 2013 12:22 am

Quoting alfablue (Reply 141):
she is grounded - isn't that a fact? A grounding after certification is no problem? two battery fires are no problems?

Fact is it was grounded because 2 separate battery incidents occured in a very short span of time and the containment of said batteries also needs to be investigated. End of story.

You stated that the 787 was plagued with all sorts of problems related to its electrical architecture. From the evidence provided so far, it appears that it may be a battery issue alone, and very little to do with the electrical architecture.

Sure there was an incident during a test/certification flight (ZA002) which was beleived to be FOD, and was subsequently modified after the fact, but that is what test flights are for. I remember watching a test flight video on the A380 during flutter testing where the fairings under the wings literally broke off the plane at high speed, but this issue was also resolved and then eventually certified.

I am just curious to here about all the other problems that the 787 is supposedly plagued with after certification aside from the incident with United and the VFSG/P200 panel.
 
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kanban
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RE: FAA Grounds 787 Part 4

Wed Jan 23, 2013 12:39 am

Quoting ContnlEliteCMH (Reply 148):
Quoting liquidair (Reply 143):
Technological advance shouldn't risk life..

Aside from the obviously incorrect historical nature of this statement -- technological advance usually involves risk to life and health -- why not?

Of course most technological advances seem to come from military applications intent on ending life and health that are then tamed for non military uses.

Quoting alfablue (Reply 151):
I just say the grounding is justified

Repeating this over and over won't cause it to happen.. the horse is dead.. we get your opinion.. just we don't give it the weight you espouse.

Quoting alfablue (Reply 154):
Read the facts than on the links.

Love the case where opinions in the press become facts .. there is too much we don't know and they don't know.

BTW, back in reply 109, I asked about the electrolyte flammability.. anyone have an answer..????
 
kellmark
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RE: FAA Grounds 787 Part 4

Wed Jan 23, 2013 12:42 am

Quoting NathanH (Reply 153):
Frankly, your hysteria on this is getting a little much. Some of us are trying to follow this and get reasoned insight into the technological issues at hand, and then you come along making hyperbolic statements and parading rumors as fact.

Nathan I have to say, in following this thread, that Alfablue makes a lot of sense, especially from the point of view of someone that puts his life and the life of his passengers on the line everyday.

I love the B787, but it is clear that fires on aircraft are fundamentally unacceptable. You can't just pull off to the side of the road. And containing a fire is great, but preventing it from happening in the first place is far better.

All three aspects of the system, the battery itself, the software controller/electrical system and the containment system have to be reviewed and examined carefully. The situation has to be duplicated to understand how it occurred. It may be that few, if any changes are required. But it is difficult to believe that at this point, especially with all of the evidence of just how unstable li-on battery systems can be in a variety of environments, and how catastrophic their failures can be. I think we have been very lucky that the 787s were not on extended overwater flights when these incidents occurred.

I also fly, as a flight instructor. And I believe that one should always mitigate risk as much as possible in aviation. And right now, we (meaning the authorities, the airlines and the manufacturer) need to have a very clear understanding of what caused this multiple occurrence problem, and what are the best ways to correct it. It may take time. Remember, it took more than a year for the investigators to determine what really happened with BA38, the 777 at LHR, with the fuel heat exchanger icing problem. I hope that it doesn't take that long here. But in comparing those two situations. Delta had an engine that had the same problem occur but it was at altitude, not on final approach. So there were two occurrences there as well, but one resulted in serious but non-fatal accident thanks to the last minute actions of the crew.

Several commenters have mentioned the DC10 accident with the #2 engine failure which knocked out the 3 hydraulic systems for the flight controls, where the aircraft crashed while attempting to land at Sioux City. For many years I worked at Eastern Airlines, and we had a similar failure to that DC10 on one of our L-1011 aircraft, as it was climbing out from EWR to SJU. The #2 engine compressor failed catastrophically, and the fan section detached from the front of the engine, went forward into the cabin of the aircraft and out the right side of the fuselage. In doing so, it cut the rudder cables, knocked out 3 of the 4 hydraulic systems and depressurized the aircraft and of course the #2 was failed. But the L-1011 did not lose all 4 hydraulic systems. It still had one left to be able to control the airplane with the elevators and ailerons, and the crew was able to land the aircraft at JFK, using differential engine power for yaw control. Ultimately, what saved the L-1011 compared to the DC10 was that the L-1011 had 4 hydraulic systems instead of 3 in the DC-10. Also, I think there was some luck involved. Subsequently, Rolls Royce put a fan brake on the front of the engine to prevent it from detaching from the engine, and Lockheed put some armored plating over the hydraulics in that area. The point being that they took several steps to mitigate the problem.

In any case, this seems that, with multiple occurrences we need to err on the side of safety, especially with fires. Alfablue is right.
 
cmf
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RE: FAA Grounds 787 Part 4

Wed Jan 23, 2013 12:58 am

Quoting wjcandee (Reply 147):
In the US as a whole, 32,310 people died in traffic fatalities in 2011, per the NHTSA. That's the equivalent of SEVEN no-survivor crashes of a fully-loaded 747-400 per MONTH, or about one every four days.

Careful, incomplete data is dangerous statistics.
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nm2582
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RE: FAA Grounds 787 Part 4

Wed Jan 23, 2013 12:58 am

Quoting lightsaber (Reply 116):
What is a 'balancer? Links are appreciated. As I prefaced, I do not claim to be a battery expert, but I'm interested in the details.

Lightsaber

A balancer is a circuit designed to equalize the voltage of all cells in a series-wired lithium battery pack assembly.

No two lithium cells are absolutely identical in capacity - the cell may be rated at 65Ah, but the reality is there is a tolerance - one cell might be 64.92Ah, and another might be 65.37Ah. They also self-discharge at differing rates (lithium cells generally self discharge at very low rates, but it still differs from cell to cell).

If you assemble a series circuit of these cells, and never make any attempt to balance them, the individual charge state of the cells will drift. The cells with the lowest capacity will experience higher voltage swings (as it takes less energy to charge them, and they have less energy to give before being discharged). Because they experience higher voltage swings, this further ages the cell and further lowers the capacity. Initially, there is nothing at all wrong with the lower capacity cells - they are within tolerance, have no defects, and are absolutely perfectly safe for use.

So let's look at a purely theoretical scenario of lithium battery usage with no balancer:

Let's assume you've made a design choice to consider 4.0V per cell to be the maximum permissible charge state (this is less than the maximum safe value for the pack - but it gives you some tolerance and also makes the pack last much longer), and let's also assume you have 8 of these cells in series. Ergo, a pack with 32V as the "max". You then charge this battery to 32V. When the pack is brand new and the cells are all close in capacity, the ending voltages (after charge) of each individual cell would be closely grouped - some at 4.00V, maybe some at 3.99V, some at 4.01V, maybe a few at 4.02V or 3.98V. But they will be very close. Over time, with use, the cells start drifting more. Eventually, one or more cells become clearly weaker (less capacity) than the others. As a result, it experiences higher voltages when the pack is charged, and lower voltages when the pack is discharged; this causes some lithium plating and other internal damage which further reduces capacity. Eventually, this weak cell fails because it experienced an over-voltage event during charging (it goes over-voltage because it can't absorb any further energy due to it's low capacity; and the chemistry of the cell dictates that it's voltage must go higher) or it fails because it fell below the minimum voltage during a discharge cycle (lithium cells are damaged by low voltage).

Now, the exact same scenario with a balancer:

Every time the pack is charged, the balancer is active. All cells are kept at exactly the same voltage. No one cell experiences any undue loads or damage because all cells are operated within their normal (safe) range. When charged to 32V, the voltages of each individual cell in the pack are exactly 4.00V. The capacity of the individual cells still varies (due to original variances in capacity when new, and due to the normal course of action as the cells age over hundreds or even perhaps a few thousand cycles) but the balancer always keeps the cells safe and in a low risk state by keeping all cells balanced at the exact same state of charge.

State of charge: the voltage of a lithium cell is directly correlated with the state of charge (the % of full capacity for that individual cell) of the cell.
 
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Stitch
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RE: FAA Grounds 787 Part 4

Wed Jan 23, 2013 1:02 am

Quoting nm2582 (Reply 162):
A balancer is a circuit designed to equalize the voltage of all cells in a series-wired lithium battery pack assembly.

So even if one of the cells in the pack is significantly degraded in comparison to it's peers, provided it receives a steady 4V during charging thanks to the load balancer, there is no risk of it entering thermal runaway or leaking electrolytes?
 
aeroblogger
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RE: FAA Grounds 787 Part 4

Wed Jan 23, 2013 1:07 am

Quoting RNAVFL350 (Reply 158):

You stated that the 787 was plagued with all sorts of problems related to its electrical architecture. From the evidence provided so far, it appears that it may be a battery issue alone, and very little to do with the electrical architecture.

There were issues with a UA aircraft's electrical system, which caused a divert to MSY. QR grounded an aircraft due to a similar issue. An Air India aircraft was grounded for a while because of issues with the airpacks, which turned out to be an electrical issue.

There is a clearly demonstrated pattern of electrical problems with this aircraft.
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Shenzhen
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RE: FAA Grounds 787 Part 4

Wed Jan 23, 2013 1:08 am

Quoting liquidair (Reply 143):
And for the people who still insist on comparing the 787 with the A350 - what on earth has that got to do with it? This isn't about A vs. B. It's about safeguarding human life as best possible- and fires on planes don't fit into that, hence the grounding.

Lets just hope that the FAA doesn't start grounding entire fleets when something happens that they can't explain (such as an airplane crashing into the ocean). Every day there are reports of smoke in the cabin. There multiple airplane fires (Egyptian 777, Turkish 737NG, Malaysian 330.......) that happen that the fleet isn't grounded. They should have mandated inspections/testing of the battery and then issued new AD's as the investigation warranted. Had there been a couple hundred 787 airplanes with "n" tail numbers flying, the fleet would not have been grounded.

This is a very slippery slope, and hopefully other regulators (countries) will allow mitigation to get the airplanes back into the air.

Cheers
 
alfablue
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RE: FAA Grounds 787 Part 4

Wed Jan 23, 2013 1:21 am

Quoting Shenzhen (Reply 165):
This is a very slippery slope, and hopefully other regulators (countries) will allow mitigation to get the airplanes back into the air.

but wouldn't mitigation of the risk be to provide ANA and other affected airlines with interim lift and do a thorough investigation into the system and its architecture and fix and re-certify what's wrong - no matter how long it takes?

I agree on the slippery slope but the question mark I have is whether rushing the 787 back into service is the solution. It seems like asking for even more troubles.

AlfaBlue
 
AeroWesty
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RE: FAA Grounds 787 Part 4

Wed Jan 23, 2013 1:24 am

Quoting alfablue (Reply 166):
the question mark I have is whether rushing the 787 back into service is the solution.

What evidence do you have that the 787 is being rushed back into service? Links to anything which would be relevant would be helpful.
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nm2582
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RE: FAA Grounds 787 Part 4

Wed Jan 23, 2013 1:25 am

Quoting Stitch (Reply 163):
So even if one of the cells in the pack is significantly degraded in comparison to it's peers, provided it receives a steady 4V during charging thanks to the load balancer, there is no risk of it entering thermal runaway or leaking electrolytes?

That's essentially correct. There are a few edge cases, but you can absolutely take an old degraded cell (perhaps one that has lost 20% of it's capacity, which is generally regarded as "end of useful life") and provided that the balancer keeps the cell voltage in the proper safe range, the cell will be as safe as any other and at no additional risk of explosion/thermal runaway/fire/etc.

Possible edge cases:

* The load balancer does not have sufficient balancing capability (i.e. it can not cope with a large imbalance, due to an inability to bleed current at the same rate that the charger is putting it in) combined with a non-integrated charger design (the charger does not reduce charge current to a rate which the balancer can effectively cope with)

* the cell has prior damage such that it is already unsafe (internal shorts, ....)
 
Shenzhen
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RE: FAA Grounds 787 Part 4

Wed Jan 23, 2013 1:31 am

Quoting alfablue (Reply 166):

but wouldn't mitigation of the risk be to provide ANA and other affected airlines with interim lift and do a thorough investigation into the system and its architecture and fix and re-certify what's wrong - no matter how long it takes?

Mitigation, as I see it, would be a comprehensive testing of the batteries and their charging systems. OHM/CMM manuals provide the means to test components on the airplane. If there is anything that the experts believe should be tested beyond, then include that in the (global AMOC) alternate means of compliance to the AD to get the birds back in the air.

Cheers
 
alfablue
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RE: FAA Grounds 787 Part 4

Wed Jan 23, 2013 1:36 am

Quoting AeroWesty (Reply 167):
What evidence do you have that the 787 is being rushed back into service? Links to anything which would be relevant would be helpful.

here you go - an article about the attitude of the Boing management - if they think the grounding is unjustified and and tell operators that all is according schedule (for april) it seems they know more than the law-makers or investigating authorities and leads me to think there is a certain rush - read for yourself - the other three links is just for you and others to see the scope into the discussion and that I still think it will not have an easy fix! after all if politicians want a hearing - is that good PR?

http://seattletimes.com/html/busines...020173453_787teethingpainsxml.html

http://www.reuters.com/article/2013/...87-norwegian-idUSLNE90L01620130122

http://www.suntimes.com/news/sweet/1...mliner-to-be-focus-of-hearing.html

http://www.aviationweek.com/Article....e-xml/AW_01_21_2013_p25-537815.xml

http://www.huffingtonpost.com/stan-sorscher/boeing-787_b_2512541.html
 
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Stitch
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RE: FAA Grounds 787 Part 4

Wed Jan 23, 2013 1:42 am



Quoting nm2582 (Reply 168):
That's essentially correct. There are a few edge cases, but you can absolutely take an old degraded cell (perhaps one that has lost 20% of it's capacity, which is generally regarded as "end of useful life") and provided that the balancer keeps the cell voltage in the proper safe range, the cell will be as safe as any other and at no additional risk of explosion/thermal runaway/fire/etc.

Thank you for that insight.


Quoting AeroWesty (Reply 167):
What evidence do you have that the 787 is being rushed back into service?
Quoting alfablue (Reply 170):
here you go - an article about the attitude of the Boing management - if they think the grounding is unjustified and and tell operators that all is according schedule (for april) it seems they know more than the law-makers or investigating authorities and leads me to think there is a certain rush

If Boeing has the power to "rush" the FAA into lifting the grounding, one would think they would have had the power to prevent it in the first place...

 

[Edited 2013-01-22 17:43:44]
 
bellancacf
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RE: FAA Grounds 787 Part 4

Wed Jan 23, 2013 1:44 am

to nm2582 at 168: The Tesla roadster has, I read elsewhere, 6831 cells in its battery. What on earth does the balancing circuit look like? Is each cell really monitored individually? There's got to be a trick in there somewhere . . . But then, if the 787 has 8 cells to be handled by each charger (there are 2 chargers, aren't there?), the comparative simplicity ought to make keeping these cells balanced a piece of cake. And if the cells are too large, well, make them smaller and do whatever it is that Tesla's doing.  
 
Shenzhen
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RE: FAA Grounds 787 Part 4

Wed Jan 23, 2013 1:45 am

Quoting alfablue (Reply 166):
but wouldn't mitigation of the risk be to provide ANA and other affected airlines with interim lift and do a thorough investigation into the system and its architecture and fix and re-certify what's wrong - no matter how long it takes?

Every year there are dozens of ADs, mandating something. An AD is not created unless someone feels there is a safety issue. Most provide up to 2, 4, 5 years (usually based on scheduled maint) to comply (after an NPRM).

The current AD provides NO means of compliance, therefore UAL (or Boeing) will need to submit an AMOC that provides their mitigation to the AD concerns, and a comprehensive risk analysis.

Cheers
 
tdscanuck
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RE: FAA Grounds 787 Part 4

Wed Jan 23, 2013 1:52 am

Quoting WingedMigrator (Reply 31):
Intuitively you can think of it this way: if you make it to 0.13 million hours with no failures, the hourly failure rate is extremely likely below 0.1 per hour (with a confidence of many nines). Pick any confidence level, say 95%, and you can compute the upper bound of the failure rate... with ZERO events. Well, actually 0.13 million successful 1-hour trails...

That method only works if you have a normal distribution (or a large sum of identically distributed distributions). In this case, we have no idea if the failure time distribution is normal (there are some good reason to think it probably isn't) and N=2 is way too low for central limit theorem to apply. With two events you can at least calculate the variance but, without knowing the distribution, even that doesn't tell you much.

Quoting DocLightning (Reply 34):
Quoting tdscanuck (Reply 14):
Since there's no chance that the FAA would have accepted a statement that "the PECS system will never leak", Boeing would have had to design the entire aft EE bay to handle chemicals flying around anyway.

But glycol and water may have very different properties than electrolyte. Is electrolyte caustic or alkaline?

I'm not a chemist but, from what I can tell, it's probably mildly caustic. I agree it's quite different than coolant, but the obvious major hazard with spraying conductive liquid into an electrical bay is shorts and that would have had to be dealt with to handle the coolant issue. Chemical reactivity is also a concern, although it would typically act much more slowly than a short (if it was wildly corrosive they couldn't have used a steel box for containment in the first place). That would at least buy you time, and any single component failure in the aft EE bay was already designed for...given what the APU battery does, any other component failure would act like a single failure in flight.

Quoting DocLightning (Reply 34):
How reactive is it? Will it burn if it gets hot or if current passes through it? I do not know. I do know that most coolants are chosen to be minimally reactive.

It's apparently flammable but I don't know under what conditions.

Quoting smolt (Reply 51):
I wonder if flight data recorder or something will tell us how much voltage and current had been applied to the battery?

It's on the flight recorder (for both batteries).

Quoting smolt (Reply 51):
If something does, how long will it take?

The DFDR has already been downloaded and decoded. If you actually have access to the hardware it's a pretty quick process.

Quoting smolt (Reply 51):
Also just interesting is if the battery is pressured and air conditioned? If not, can the lithium put up with so frequently
pressure and temperature going ups and downs inside commercial aircraft?

All the EE bay compartments are part of the pressure vessel, so they experience basically the same pressure as the passengers (modulo a small differential that drives the cooling air flow). Temperature in the EE bay is typically a little higher than the cabin because of the high power density.

Quoting liquidair (Reply 57):
I'm no engineer, pilot or expert- buy I do know that I wouldn't get on a plane where things catch fire.

Then you should never get on a plane...stuff catches fire on planes quite often. The vast majority of the time it's stuff that's not part of the aircraft itself (cargo or garbage), which is why the airplane is designed to handle it. There are also flammable components that are part of the airplane by its design (fuel, oil, batteries, oxygen generators). Since these can't be designed out, the airplane has to be build to deal with them if they catch fire.

Quoting liquidair (Reply 57):
The fact of the matter is that accidents happen when an unforseen set of events come together to create an incredibly improbable outcome.

Yes. Fortunately, in this case, a battery fire was a foreseen event and designed for. The problem is that it wasn't supposed to happen this often, so the probability of interaction with other events is out of whack...it's those interactions that drive the certification of multiple failures via fault tree analysis, so changes to the input probabilities need to be carefully studied to see if the high level combinations threaten the aircraft to an unacceptable degree.

Quoting liquidair (Reply 57):
And whichever way you look at it, pissing out liquid stuff all over the EE bay is not good design- it's a failure.

Yes. But individual components on aircraft fail quite regularly; that's why no single failure is allowed to threaten safe flight and landing, regardless of how likely the failure is. Interactions are dealt with on a probability basis. The big open question, in this case, is if battery fires are more likely than expected, how does that interact with all the other systems. If a battery fire, by itself, could threaten safe flight of the aircraft then it would never have been certified in the first place.

Quoting AlfaBlue (Reply 58):
The Qantas incident was never supposed to happen and yet it did but only few criticized the failure of the nacelle (which should have contained the debris of an exploding engine).

No. You're confusing blade containment (which is a requirement) with rotor burst containment (which isn't). The nacelle in the Qantas event did not fail. There is no known practical way to contain a rotor burst; that's why it's a design requirement for the rest of the airplane that it be able to withstand a rotor burst (which the A380 did). That it did so is a testament to the A380 engineers *and* the flight crew...the engineers made sure that the flight crew had an aircraft that was even capable of flight (despite an incredibly unlikely rotor burst that cut two independent, separated, and redundant wires).

Quoting AlfaBlue (Reply 58):
Reading some of the posts defending the container as a prove of safety is just beyond missing or understanding what safety means.

I don't think anybody has defended the containment as proof of safety; they have defended it as potentially proof of containment, which was the whole point. Neither aircraft was rendered incapable of safe flight and landing, which is the real requirement.

Quoting AlfaBlue (Reply 58):
For some armchair CEO, safety experts and wanna be pilots I can promise you that a fire outside the engine hot section is a non acceptable risk no matter what underlying statistic tools you use for its likelihood or its containment.

You need to include the FAA, EASA, all other regulators, and all OEM's into that pile then. A fire outside an engine hot section *is* an acceptable risk if the fire, by itself, won't bring down the aircraft (through any combination of mitigation tools, including suppression, detection, and containment) and if the probability of the fire, when combined with the probability of other failures, is less than 1e-9 to bring down the aircraft. This is how aircraft have been certified for decades.

Quoting AlfaBlue (Reply 58):
IMHO this technology should have not been approved for airline operation and contrary to what many seem to believe here the JAL Boston incident would have warranted a grounding already.

How would the JAL Boston incident warrant grounding by itself?

Quoting AlfaBlue (Reply 58):
This aircraft has a deeply flawed electrical system and the recent incidents just made that very clear to very many people.

What are the specific deep flaws that you're concerned about? The battery is obviously one. What are the others?

Quoting AlfaBlue (Reply 63):
That's just another layer of safety but the batteries are not supposed to light up in the first place.

Yes. And engines aren't supposed to have rotor bursts, airplanes aren't supposed to get hit by lightning, and passengers aren't supposed to put lit cigarettes in the garbage. But all these things happen and cannot be absolutely prevented, so the designers make sure that, if these things happen, the aircraft can still get the passengers safely to the ground.

Quoting AlfaBlue (Reply 63):
The engine is not supposed to fail in a fashion that parts fly around but in the event it happens it should be contained

No. No jet aircraft ever build has had the ability to contain a rotor burst.

Quoting AlfaBlue (Reply 63):
Do you get the concept that in modern aviation I don't want things on board over the ocean that light up for an unknown reason and right next to all vital systems and I have no tools to prevent that or mitigate the effects except praying that the engineers didn't built in a design flaw into the container (as we saw with RR and the A380).

1) The engineers didn't build a design flaw into the A380 "container"...the entire rest of the system performed as designed, given that a rotor burst occured (it is physically impossible to engineer rotor bursts out completely).
2) It's obvious that flight crews (or anybody else) don't *want* fires for any reason. This is not a reason to not engineer protections in in case do occur.

Quoting AlfaBlue (Reply 63):
The container is not relevant here - it's the fact that you have a fire on board you can not control - contained or not - it does not matter!

The container is hugely relevant; the container (and other protective design features) is the reason that the second JAL flight ended in an evacuation with minor injuries, rather than something somewhere between massive smoke inhalation injuries and a hull loss. It's also the reason that the aircraft from the first event is sitting entirely intact on the ramp in Boston, rather than being a charred pile of carbon fiber.

Quoting AlfaBlue (Reply 65):
I think we have safer battery tech available and saving some weight and improving economics is no acceptable reason to endanger lives.

Lives are endangered every time anybody flies (or does almost anything). The point is to reduce risk to an acceptable level (the level is well defined and hasn't changed for a very long time). Jet engines have killed far more people than airplane battery fires...should we get rid of jet engines?

Quoting AlfaBlue (Reply 65):
Yes - based on recent evidence I would suggest that the certifying bodies DO NOT allow the use of lithium batteries in commercial aircraft.

What is the basis for banning an entire technology, rather than a particular implementation of it? Battery fires did not begin with lithium batteries.

Quoting liquidair (Reply 68):
How many mass produced passenger jets are there with lith-ion batteries?

At this point, a couple of hundred.

Quoting liquidair (Reply 68):
Which were designed to have failing thermal runaway fires?

All of them.

Quoting liquidair (Reply 68):
It's not a question of designing in the containment- there shouldn't be this issue in the first place.

That's a single-point failure approach ("Don't design for failure, just have it not fail."). In addition to being terrible engineering practice, it's flat-out illegal. You can't certify any aircraft under that basis.

Quoting PlaneInsomniac (Reply 74):
The amount of word mincing, pseudo-legal babble, and over- and re-interpretation of published information for the sole purpose of downplaying the problem in this forum has reached unimaginable proportions.

The discourse around this topic falls into three main buckets:
1) Requests for clarification
2) Attempts to downplay the problem
3) Attempts to "upplay" the problem

Much of the detailed discussion is around 1), which is great and what a.net is best at. Relatively little (although not zero) has been 2). Considerably more has been around 3), which is why a great deal of explanation is going on. Much as legal terms have particular definitions in the courts that don't necessarily match the lay definition, the same thing happens with aviation (both on the engineering and certification side). Using the lay definition or not being very technical may lead to very erroneous conclusions if you're not careful.

Quoting AlfaBlue (Reply 79):
Why did the Boeing management flip upon the news of the grounding? Because they know about the flaws and the flawed elec. system and now the whole world knows and vividly discusses it too.

Why on earth would Boeing management pick the most damaging and most expensive possible path? Even if you're so cynical as to think that Boeing was only chasing $$$, knowing the system is fatally flawed and covering it up is far more expensive than any other alternative. There is no possible reason for them to take the path you're claiming.

Quoting spacecadet (Reply 85):
Lots of planes end up being certified with foreseeable design defects;

All planes end up being certified with foreseeable design defects. That's what most AD's are about.

Quoting AlfaBlue (Reply 88):
We should all fight for the right to let Boeing and other manufactures use us as live lab rats to prove or disprove a new technology.

This argument would apply to all technologies ever introduced in aviation. If you want to freeze aviation technology at some point, which point are you picking?

Quoting alfablue (Reply 100):
I used the nacelle sample because its close enough as an example to what the containment is supposed to do with the battery.

No, it's not. The nacelle wasn't designed to contain a rotor burst, the battery box was designed to contain the damage from a battery fire. In both cases, so far, it looks like the design worked as intended.

Quoting alfablue (Reply 107):
I for example never understood neither why the Airbus A380 could fly with wings braking before the limit and than just present a computer program calculation or whatever

Because the major purpose of the test isn't to prove the strength of the structure, it's to validate the tools used to design the structure. Once you calibrate the tools, you have very high confidence in the accuracy of small changes from the test article. If the wing had broken at 100% instead of 150%, you can bet the regulators would have made Airbus break another one. But they got to something like 147%. With that data, showing the impact of the strengthening is very straightforward. It would require an absolutely enormous analysis failure (about two orders of magnitude higher) to not get from a tested 147% to an analyzed 150%.

Quoting alfablue (Reply 121):
I mean where does economics versus safety stop.

When the risk balances the cost. That's how transportation systems have been done since long before airplanes were invented. In the particular case of aviation, the scale has actually swung way over to the safety side relative to other forms of transport; we're far more tolerant of risk on cars and trains (and even walking) than we are on airplanes.

Quoting alfablue (Reply 121):
Whats wrong with being on the safe side?

Within reason, nothing. But going all the way to "absolute safety", as some have called for in this discussion, means ending commercial aviation entirely.

Quoting alfablue (Reply 127):
Quoting Cubsrule (Reply 124):
Do you believe that the 380 should be grounded until the lithium ion batteries are removed from its emergency lighting system?

If they are a danger to flight safety than yes.

They're not a danger to flight safety. Neither were the 787 batteries, by themselves. What's up in the air is compound failures.

Quoting liquidair (Reply 143):
Technological advance shouldn't risk life

Technological advance always risks life, in as much as the mere process of flying has some risk. This is a variant of the "absolute safety" argument.

Tom.
 
Shenzhen
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RE: FAA Grounds 787 Part 4

Wed Jan 23, 2013 1:54 am

By Andrea Shalal-Esa

WASHINGTON (Reuters) - A key Senate committee will hold a hearing in coming weeks to examine U.S. aviation safety oversight and the Federal Aviation Administration's decision to allow Boeing Co to use highly flammable lithium-ion batteries on board its new 787 Dreamliner, a congressional aide said on Tuesday.

Wow, and this isn't political?
 
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DocLightning
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RE: FAA Grounds 787 Part 4

Wed Jan 23, 2013 2:02 am

Quoting Shenzhen (Reply 165):
Lets just hope that the FAA doesn't start grounding entire fleets when something happens that they can't explain (such as an airplane crashing into the ocean).

If it had happened twice in two days, then I would have argued that the A330 fleet world-wide should be grounded. It didn't for a very good reason: it was crew error. The cause, although not known, was the reason why two such events did not occur in rapid succession.

Quoting Shenzhen (Reply 165):
Every day there are reports of smoke in the cabin.

Again, when it happens on two aircraft of one type within a few days due to malfunction in the same component, then it should be grounded. Especially when it is a new type with only 50 frames flying and less than 60,000 flight hours total.

Bottom line: the number of events per flight hour should be low. In this case, two such events in the 787 fleet in 72 hours would correspond to >10 such events every day in the worldwide A330 fleet. If that were happening, you bet the A330 fleet would be grounded. And, in fact, after the AS MD80 went swimming off Point Mogu, the MD80 fleet was grounded until the jackscrew inspections could be done.
-Doc Lightning-

"The sky calls to us. If we do not destroy ourselves, we will one day venture to the stars."
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PHX787
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RE: FAA Grounds 787 Part 4

Wed Jan 23, 2013 2:06 am

Quoting Shenzhen (Reply 175):
WASHINGTON (Reuters) - A key Senate committee will hold a hearing in coming weeks to examine U.S. aviation safety oversight and the Federal Aviation Administration's decision to allow Boeing Co to use highly flammable lithium-ion batteries on board its new 787 Dreamliner, a congressional aide said on Tuesday.

Well they have every right to inspect it. I mean, Japanese government is getting involved too.

We just don't need anything bad happening anymore to aircraft
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par13del
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RE: FAA Grounds 787 Part 4

Wed Jan 23, 2013 2:09 am

Quoting Stitch (Reply 171):
If Boeing has the power to "rush" the FAA into lifting the grounding, one would think they would have had the power to prevent it in the first place...

Stop, you are starting to make sense  
Quoting Shenzhen (Reply 175):
WASHINGTON (Reuters) - A key Senate committee will hold a hearing in coming weeks to examine U.S. aviation safety oversight and the Federal Aviation Administration's decision to allow Boeing Co to use highly flammable lithium-ion batteries on board its new 787 Dreamliner, a congressional aide said on Tuesday.

This one makes absolutely no sense, we all know that the politicians in the USA are in Boeing's back pocket, see the illegal subsidies and the bogus tanker contract, why would they do this, is there no loyalty?
 
WingedMigrator
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RE: FAA Grounds 787 Part 4

Wed Jan 23, 2013 2:16 am

Quoting tdscanuck (Reply 174):
That method only works if you have a normal distribution

A normal distribution is not relevant to the problem at hand. Confidence levels can be calculated for the Poisson distribution just as they can for any PDF, and the Poisson distribution is relevant here because it describes the behavior of discrete, rare events... such as battery failures. Poisson statistics allow you to infer a failure rate even if you haven't observed a single failure, provided that the underlying failure rate is constant. The basic N=2 logic, where N is the number of observations, doesn't apply because lack of failure is also an observation.
 
AeroWesty
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RE: FAA Grounds 787 Part 4

Wed Jan 23, 2013 2:16 am

Quoting alfablue (Reply 170):
leads me to think there is a certain rush

So you've gone from asking, "whether rushing the 787 back into service is the solution," as if this was a foregone conclusion based on factual events, to now it's just your opinion being that the process is being rushed when asked to back it up.

Quoting Stitch (Reply 171):
If Boeing has the power to "rush" the FAA into lifting the grounding, one would think they would have had the power to prevent it in the first place.

   We just have a pot-stirrer in our midst, best I can tell.
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tdscanuck
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RE: FAA Grounds 787 Part 4

Wed Jan 23, 2013 2:17 am

Quoting alfablue (Reply 151):
point 2 : would you have rather seen a battery fire in the news on a transoceanic flight? Thanx heavens they were close to an airport where they could land! They had a fire onboard!!!
Quoting kellmark (Reply 160):
I think we have been very lucky that the 787s were not on extended overwater flights when these incidents occurred.

This is the type of "upplaying" I was talking about. Battery fire was a design condition; not one that anybody expected would even be called into play (like most design conditions) but one that, should it occur, could not impact safe flight and landing. This is certification 101 stuff.

Quoting alfablue (Reply 151):
I just say the grounding is justified and should not be lifted after a deep investigation into many of the 787 development, outsourcing, documentation and certifying is conducted

I'm really hoping you meant "and *should* be lifted" in that sentence. If not, are you suggesting grounding the 787 forever?

Quoting alfablue (Reply 151):
I wish I could sit you on a 787 over the pacific ant test the containment box 1000 times and see if it always holds what it promises!

As someone who actually sat in a 787 over the Pacific (and other environs) with intentionally inserted failures far more dangerous than this one, I'd happily go out and test the containment box as you describe. That would, however, be a lousy test design, you could do much better (and I would assume that Boeing, the FAA, and NTSB are doing just that).

Quoting liquidair (Reply 152):
I'll reiterate- accidents occur when something happens that wasn't foreseen, most likely extremely improbable. But they do happen and as such a flaming battery on a new plane is really serious

But a flaming battery was a foreseen failure. I'm confused why this keeps coming up.

The regulators will *never* let you claim something will never fail. They flat out won't accept that. You have to show that any failure, regardless of how unlikely. From the FAA:
"a. The following basic objectives pertaining to failures apply:

(1) In any system or subsystem, the failure of any single element, component, or connection during any one flight (brake release through ground deceleration to stop) should be assumed, regardless of its probability. Such single failures should not prevent continued safe flight and landing, or significantly reduce the capability of the airplane or the ability of the crew to cope with the resulting failure conditions."

The issue with the current problem is that it might not comply with regulations that require the probability of a catastrophic event due to foreseeable *combinations* of failures must be extremely remote.

Quoting RNAVFL350 (Reply 156):
I am pretty sure that the fuel carried on the airplane is also a potential source of fire with no extinguishers as well.

Actually, the 787 at least has a flammability reduction system in all tanks (as will the A350). That's not going to help if you start a fire in there, but it will reduce the probability of a fire. Those arguing that Jet-A is proven safe should remember that the FAA actually reversed course on that about 10 years ago and mandated flammability reduction systems on new types.

Quoting kellmark (Reply 160):
I have to say, in following this thread, that Alfablue makes a lot of sense, especially from the point of view of someone that puts his life and the life of his passengers on the line everyday.

What of the lives of the flight crews and engineers who took the plane up and inserted failures worse than Alfablue will likely ever see in service, just so that certification could be granted and Alfablue could fly the plane in the first place? There seems to be this pervasive, very wrong, idea that the engineers and pilots who make these design decisions aren't directly impacted by them. Many of them fly on the tests that make those very failures happen (and yes, those tests sometimes include fires).

Quoting kellmark (Reply 160):
I love the B787, but it is clear that fires on aircraft are fundamentally unacceptable. You can't just pull off to the side of the road. And containing a fire is great, but preventing it from happening in the first place is far better.

Nobody would agree with you more than the OEMs. Prevention is, by far, the preferred option. But it is unacceptable to have it be the only option. *Even* if you do all that's physically possible to prevent the fire, you should still plan for mitigation in case it does occur.

Quoting kellmark (Reply 160):
It may take time. Remember, it took more than a year for the investigators to determine what really happened with BA38, the 777 at LHR, with the fuel heat exchanger icing problem.

And note that the 777 fleet kept flying (safely!) all that time. This issue was actually considerably more of a threat, since it was an unforeseen common mode failure.

Tom.
 
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RE: FAA Grounds 787 Part 4

Wed Jan 23, 2013 2:19 am

Quoting DocLightning (Reply 176):
Again, when it happens on two aircraft of one type within a few days due to malfunction in the same component, then it should be grounded. Especially when it is a new type with only 50 frames flying and less than 60,000 flight hours total.

Bottom line: the number of events per flight hour should be low. In this case, two such events in the 787 fleet in 72 hours would correspond to >10 such events every day in the worldwide A330 fleet. If that were happening, you bet the A330 fleet would be grounded. And, in fact, after the AS MD80 went swimming off Point Mogu, the MD80 fleet was grounded until the jackscrew inspections could be done.

Its not the bottom line (maybe yours). When an Egypian 777 flight deck burns due to an oxygen fire, the FAA mandates changes to the crew oxygen system, because there is a safety issue in the design, why not ground the fleet to ensure it doesn't happen again, but this time in flight? Why wait for an expert analysis understand the risk? How do we know it won't happen tomorrow, it did happen yesterday?

Was the MD80 fleet just grounded, or was there an inspection (such as freeplay) that was required before further flight?

When the A330 went down, nobody knew why until sometime after the event. Why not ground the fleet, after all, safety is number one, no?

Quoting par13del (Reply 178):
WASHINGTON (Reuters) - A key Senate committee will hold a hearing in coming weeks to examine U.S. aviation safety oversight and the Federal Aviation Administration's decision to allow Boeing Co to use highly flammable lithium-ion batteries on board its new 787 Dreamliner, a congressional aide said on Tuesday.

This one makes absolutely no sense, we all know that the politicians in the USA are in Boeing's back pocket, see the illegal subsidies and the bogus tanker contract, why would they do this, is there no loyalty?

The NLRB sued Boeing because they opened a new 787 factory in South Carolina. The SC governor laughed at the current administration during the Republican Convention.

I don't think there is much happiness between the current US government and Boeing.

Cheers
 
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Stitch
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RE: FAA Grounds 787 Part 4

Wed Jan 23, 2013 2:21 am

Quoting Shenzhen (Reply 175):
WASHINGTON (Reuters) - A key Senate committee will hold a hearing in coming weeks to examine U.S. aviation safety oversight and the Federal Aviation Administration's decision to allow Boeing Co to use highly flammable lithium-ion batteries on board its new 787 Dreamliner, a congressional aide said on Tuesday.

Wow, and this isn't political?

Well they just extended the US debt ceiling until May, so they evidently have some free time on their hands...  
 
RickNRoll
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RE: FAA Grounds 787 Part 4

Wed Jan 23, 2013 2:22 am

Quoting wjcandee (Reply 147):
The design issue is and always has been to contain the things that are anticipated occasionally to catch fire or to limit their effects, just as is it to contain the things that will always be on fire and will sometimes explode. Things can and will catch fire, fail, or go boom on an airplane, but good design will minimize or eliminate their effects, such that the event is non-catastrophic, and hopefully not even serious.

I find it hard to accept that the battery in the second incident was 'designed' to fail the way it did. What appears to have happened from the photo is that enough pressure built up in the container that it managed to squeeze up the corners away from the screws anz ooze and bubble out. It just doesn't look like a 'design' to me.
 
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RE: FAA Grounds 787 Part 4

Wed Jan 23, 2013 2:23 am

Quoting Stitch (Reply 142):
Boeing's mandatory retirement age is 65

Sorry for the off topic, but I'm curious about this.... Is this for higher ups only or for all Boeing employees?

As for the topic at hand, what is the target date to get the 787's back in the air? What's the earliest they can get?

And I would have no problems flying on the 787.
A Safe Flight Begins With Quality Maintenance On The Ground.
 
Shenzhen
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RE: FAA Grounds 787 Part 4

Wed Jan 23, 2013 2:24 am

Quoting tdscanuck (Reply 181):
his is the type of "upplaying" I was talking about. Battery fire was a design condition; not one that anybody expected would even be called into play (like most design conditions) but one that, should it occur, could not impact safe flight and landing. This is certification 101 stuff.

There are operator reports of airplane thermal damage due to batteries overheating in "non" 787 airplanes. Maybe the FAA will bring these reports to the Senate hearings?
 
Shenzhen
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RE: FAA Grounds 787 Part 4

Wed Jan 23, 2013 2:28 am

Quoting tdscanuck (Reply 181):
Quoting kellmark (Reply 160):
It may take time. Remember, it took more than a year for the investigators to determine what really happened with BA38, the 777 at LHR, with the fuel heat exchanger icing problem.

And note that the 777 fleet kept flying (safely!) all that time. This issue was actually considerably more of a threat, since it was an unforeseen common mode failure.

Tom.

They actually "mitigated" the effects of the snowballing in the exchanger by requiring flights crews to push the throttles forward before their decent. Worked great, as there were additional flameouts, but at altitude, where procedures allowed a re-light (and no mass groundings).
 
prebennorholm
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RE: FAA Grounds 787 Part 4

Wed Jan 23, 2013 2:37 am

Quoting Stitch (Reply 131):
Per the A350 Systems Description, the A350 uses four identical Lithium-Ion batteries connected to the 28V DC network.
Quoting Stitch (Reply 131):
Will EASA require additional testing of these four batteries to ensure they will neither catch fire nor leak electrolyte?

One thing is sure, Airbus will never try to have a similar design certified by EASA. To even try to have a dozen CAAs and the airlines accept that after all this, that would be an uphill battle which nobody would even try to fight.

They will contain those batteries in a way so they can burn safely and and emit all smoke and smell out of the plane without even touching EE-bays, cargo hold or cabin.

Maybe that has always been their design, I don't know. But if not, then sure it will be long time before first test flight.

It will be heavier per w/h than the present 787 design. But since nobody can guarantee no Li-Ion thermal runaway, then they have no other choice.

Except maybe that customers demand Li-Ion free planes, and they revert to 330/340 battery technology.

Following this investigation there will be updated data on general liability of Li-Ion. If those data indicate a maintenance or reliability nightmare, then customers (the airlines) will of course demand Li-Ion free planes.
Always keep your number of landings equal to your number of take-offs
 
bellancacf
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RE: FAA Grounds 787 Part 4

Wed Jan 23, 2013 2:41 am

Here's an excerpt from Wikipedia's "Tesla Roadster" article. Non-propagation of thermal runaway and constant cooling are emphasized. Note that this article says that the type of battery is unclear; elsewhere, I believe that I saw LiCo given as the type. But, yeah, 11 sheets * 9 bricks/sheet * 69 cells/brick = 6831 cells. I wonder what the other people in the room said when _that_ first was scribbled on the whiteboard. It seems that there is quite another way of using LiCo cells to do about the same thing. However, this assembly is charged from the very predictable grid, not from fluctuating sources -- does anyone have an opinion on whether that rules out this many-little-cells approach?

Quote: "Battery system

Connected power supply

Tesla Motors refers to the Roadster's battery pack as the Energy Storage System or ESS. The ESS contains 6,831 lithium ion cells arranged into 11 "sheets" connected in series; each sheet contains 9 "bricks" connected in series; each "brick" contains 69 cells connected in parallel (11S 9S 69P). The cells are of the 18650 form-factor commonly found in laptop batteries. Sources disagree on the exact type of Li-Ion cells - GreenCar says lithium cobalt oxide (LiCo),[104] while researchers at DTU/INESC Porto state lithium manganese oxide (LMO).[105] LiCo has higher reaction energy during thermal runaway than LMO.[106]

The pack is designed to prevent catastrophic cell failures from propagating to adjacent cells (thermal runaway), even when the cooling system is off.[107] Coolant is pumped continuously through the ESS both when the car is running and when the car is turned off if the pack retains more than a 90% charge. The coolant pump draws 146 watts.[41][108][109][110]

A full recharge of the battery system requires 3½ hours using the High Power Connector which supplies 70 amp, 240 volt electricity; in practice, recharge cycles usually start from a partially charged state and require less time. A fully charged ESS stores approximately 53 kWh of electrical energy at a nominal 375 volts and weighs 992 lb (450 kg).[111][112]"
 
Shenzhen
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RE: FAA Grounds 787 Part 4

Wed Jan 23, 2013 2:44 am

Quoting Stitch (Reply 183):

Well they just extended the US debt ceiling until May, so they evidently have some free time on their hands...

Too funny, isn't it? They probably know as much about batteries as they do budgets  

Cheers
 
tdscanuck
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RE: FAA Grounds 787 Part 4

Wed Jan 23, 2013 2:44 am

Quoting RickNRoll (Reply 184):
I find it hard to accept that the battery in the second incident was 'designed' to fail the way it did.

The batteries are never designed to fail. The rest of the aircraft is designed to keep flying safety *if* the battery fails. That's what people mean why they say a failure was "designed for."

Tom.
 
ikramerica
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RE: FAA Grounds 787 Part 4

Wed Jan 23, 2013 2:45 am

Quoting Shenzhen (Reply 175):

It's political and corrupt.

Japan, in an effort to save face, grounds the 787 without sufficient reason. This may be in response to criticism after the tsunami where it was demonstrated Japan was too late to take action regarding safety and allowed nuclear plants to decide if they were safe rather than an oversight agency.

Not to look like they don't care about safety as much as Japan, and possibly as punishment for opening a 787 FAL in a *gasp* right to work state and gor outsourcing so much to other nations, and likely under pressure from France who opened their own investigation for some reason, the US grounded the 787 for nebulous reasons based on hypothetical possible risk of something that hasn't actually happened, and for which the aircraft was designed with redundancies and containment, with NO answer on how anyone might comply and return the 787 to the skies.

These moves will cost Boeing 100s of millions of dollars for no reason, no loss of life, no incidents any more severe than the hundreds of other evac incidents around the world every year.

Why wasn't the 747 grounded after TWA 800? Or after the side ripped off over the Pacific? Why wasn't the A330 grounded after the AF hull loss? Why wasn't the A380 grounded while the engine issue was solved? Why were check and go good enough for those cases but not now?

Now, not to be outdone and never one to not take the opertinity to look like they care about anything but lobbying money, the Senate will investigate how such an "unsafe" aircraft could possibly be certified.
Of all the things to worry about... the Wookie has no pants.
 
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Aesma
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RE: FAA Grounds 787 Part 4

Wed Jan 23, 2013 2:53 am

About car accidents, need I explain the differences with airplanes crashing ?

Anyway I'm betting that when autodrive is safe/cheap/reliable it will become illegal to drive ones car. At first it will only be people failing medical tests or strict driving tests. Then everybody, because the risk is just too great.
New Technology is the name we give to stuff that doesn't work yet. Douglas Adams
 
RickNRoll
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RE: FAA Grounds 787 Part 4

Wed Jan 23, 2013 2:57 am

Quoting tdscanuck (Reply 191):
The batteries are never designed to fail. The rest of the aircraft is designed to keep flying safety *if* the battery fails. That's what people mean why they say a failure was "designed for."

Engines have protection for blades flying off and fire extinguishers in case of fire. They are designed to cope with failure. I can't see where the batteries are. A fire extinguisher won't apply in this case, but a workable venting or other containment mechanism that is more sophiscated than random oozing out of cracks at the top of the battery where the lid is screwed on would be more appropriate, IMHO.
 
Shenzhen
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RE: FAA Grounds 787 Part 4

Wed Jan 23, 2013 3:10 am

Quoting RickNRoll (Reply 194):
Engines have protection for blades flying off and fire extinguishers in case of fire. They are designed to cope with failure. I can't see where the batteries are. A fire extinguisher won't apply in this case, but a workable venting or other containment mechanism that is more sophiscated than random oozing out of cracks at the top of the battery where the lid is screwed on would be more appropriate, IMHO.

What about the turbine disk that went through the side of a T-tail and killed a passenger. What about the BIG hole in front of the engine, what protection does that provide for blades that decide to depart a failing engine and are flung forward of the kevlar containment rings?. How about a combustion chamber burn through that melts a strut, yet no groundings?

Nothing is perfect.

How does the APU get its fuel from the wing, hmmmmm that must be unsafe. What if some fuel leaks from the hose and spills through the shroud... that could certainly fuel a fire.

Time to buy stock in the government owned Railroad  

Cheers
 
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kanban
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RE: FAA Grounds 787 Part 4

Wed Jan 23, 2013 3:56 am

Quoting alfablue (Reply 166):
rushing the 787 back into service is the solution.

Nobody is rushing the plane back into service, they are rushing to understand the cause... your comment is typical trolling

Quoting Shenzhen (Reply 175):
Wow, and this isn't political?
Quoting par13del (Reply 178):
This one makes absolutely no sense, we all know that the politicians in the USA are in Boeing's back pocket, see the illegal subsidies and the bogus tanker contract, why would they do this, is there no loyalty?

Trolling again?... yes Congress will hold hearings, part of their job it to look like they care. but it's not the subject here.

Quoting AirframeAS (Reply 185):
Sorry for the off topic, but I'm curious about this.... Is this for higher ups only or for all Boeing employees?

Top ranks only, there's a limit on the Board as well but I think it's higher... there are still one or two employees that built B-17's on the payroll.

Quoting RickNRoll (Reply 184):
What appears to have happened from the photo is that enough pressure built up in the container that it managed to squeeze up the corners away from the screws anz ooze and bubble out. It just doesn't look like a 'design' to me.

Now your a design expert...? or are you still trolling? THE BOX DID EXACTLY WHAT IT WAS SUPPOSED TO DO... got it? Flames did not fill the electrical bay, burn through the CFRP, warm the buns in steerage, the runaway was contained exactly the way the engine cowling contains most of the engine when one fails.. however from you comments we should seal up both ends of the nacelle preventing any air movement through the engine in addition to the sidewall containment.
 
cornutt
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RE: FAA Grounds 787 Part 4

Wed Jan 23, 2013 4:24 am

Quoting AirframeAS (Reply 185):
As for the topic at hand, what is the target date to get the 787's back in the air? What's the earliest they can get?

Good question. Considering a fairly optimistic scenario... let's say that they determine tonight that the problem is a manufacturing problem with the batteries that failed, and that they are able to devise a battery test procedure that can be executed at airline maintenance facilities. I'd guess it would take two days minimum (of squadrons of people working around the clock) to prepare the necessary data to substantiate the safety case, and another two days of around-the-clock for the FAA to review and approve the data. During this time, the FAA allows airlines to ferry their planes back under some temporary flight restriction (e.g., batteries disconnected, APU started on ground power and remains running throughout the flight). So after four days, the airlines have an approved test procedure, and aircraft queued up. I have no clue how long it takes to remove the batteries from the aircraft using normal maintenance procedures; let's say that they can turn around one aircraft per day -- remove the batteries, test them, and reinstall them assuming they pass the test. So the earliest that a 787 could be put back into revenue service in this scenario would be Monday the 28th. After that, it would be one aircraft per day for each airline, less any aircraft that need their batteries replaced -- I don't know how many might be in stock, and any that are have to be tested too.

So the absolute minimum for getting all delivered 787s back into service appears to be about five weeks from when the solution is found. And that's assuming an awful lot of people are working day and night.
 
prebennorholm
Posts: 7029
Joined: Tue Mar 21, 2000 6:25 am

RE: FAA Grounds 787 Part 4

Wed Jan 23, 2013 4:37 am

Quoting ikramerica (Reply 192):
...France who opened their own investigation for some reason...

The reason is clearly that they will make sure that such an incident on for instance an A350 is a lot better contained.

Quoting RickNRoll (Reply 194):
...but a workable venting or other containment mechanism that is more sophiscated than random oozing out of cracks at the top of the battery where the lid is screwed on would be more appropriate, IMHO.

Exactly. Something like that will be the end of this story.

The technicians can fight all the battles they want over this issue, whether it was contained well enough and such. But for Boeing to win the war they have also have to win the PR battle. And they have to win acceptance not just from the FAA, but also from all involved CAAs around the world.

If they walk the way that they try to convince the world that this incidence was contained well enough, then they will lose the war.

The price will be a little weight growth and possibly a few ft3 reduced cargo space. The sooner they start working on this outcome, the sooner the plane will fly again.
Always keep your number of landings equal to your number of take-offs
 
tdscanuck
Posts: 8572
Joined: Wed Jan 11, 2006 7:25 am

RE: FAA Grounds 787 Part 4

Wed Jan 23, 2013 4:41 am

Quoting cornutt (Reply 197):
I have no clue how long it takes to remove the batteries from the aircraft using normal maintenance procedures; let's say that they can turn around one aircraft per day -- remove the batteries, test them, and reinstall them assuming they pass the test. So the earliest that a 787 could be put back into revenue service in this scenario would be Monday the 28th.

In a situation like that, especially since the number of airlines is low, seed units are a virtual certainty.

Boeing would pre-emptively do the test procedure on all batteries in spare stock and at the vendor...as soon as approval was granted, those known-good batteries (the seed units) would be on overnight freight (with appropriate shipping paperwork and packaging, obviously) to the airlines. They would pull the battery from an aircraft, insert the known good battery, and send that aircraft on it's way while they were testing the removed battery. So the turn time for the aircraft would just be the time to swap the battery (probably about an hour). Provided spare parts are available (which they've got to be...if nothing else, they could be pulled from aircraft on the production line), this is a pretty normal way to get through a part inspection more quickly. It's been used before on other problem LRUs on other types.

Depending on the nature of the inspection, I'd expect Boeing and regulator teams to be shipside to do it as quickly as possible.

That's all *if* it's an inspectable problem...that would be a great outcome, given what's already happened.

Tom.
 
YVRLTN
Posts: 2339
Joined: Wed Oct 04, 2006 1:49 pm

RE: FAA Grounds 787 Part 4

Wed Jan 23, 2013 4:42 am

Quoting kanban (Reply 109):
we have discussed that the electrolyte is flammable.. but at what temperature? does the boiled extruded goo have the same or a significantly high ignition temperature?

I dont know the answer, but from the photo from Shamu330 in post 207 in thread 3, as well as the green substance there does seems to be some brown scorch marks too on the fuselage. That suggests it was pretty hot temperature wise (despite hitting the cold air outside) or it was flammable enough to interact with the fuselage to cause scorching.

For that stuff to be flowing inside the aircraft, I can see it would be pretty nasty *if* it touched any wires or anything else critical, but I assume for this very reason there would be nothing that would be effected in the vicinity or path to the outlet valve? Would be nice to see lower in the photo ADent provided in post 105 of this thread.

That being said and my assumption being the truth, I do feel the containment worked as best as could possibly be hoped for.

Quoting kanban (Reply 109):
the A350 will be using similar batteries (4 instead of 2) and I've seen a few notes that they are following this investigation very closely

I cant find the post now, but I asked the question at the end of a thread that was locked which was never answered where someone mentioned the huge purchase cost for these types of batteries vs those used even in the 764 (a similar sized aircraft).

I assume the whole purpose of using these batteries is to save weight = fuel burn. However, if they have to be replaced on an annual basis (the NH one may have been for example) or certainly far more regularly than current batteries, would the cost saving in fuel really cover the actual outlay costs of the batteries themselves? I cant remember the numbers unfortunately, but the fuel saving seemed relatively paltry in comparison to the outlay costs.

What Im getting at is obviously Boeing cant go back with the 787 (unless in the highly unlikely event that the FAA request otherwise) but Airbus may have a choice with the A350, even if it causes a delay, and they are no doubt looking into this.

Quoting UALWN (Reply 157):
As far as I know, there has not been any fire attributed to the Li ion batteries in the almost 100 A380s that are flying since first entering service over 5 years ago

AFAIK there has been no need to use these batteries in commercial service? Apart from being a smaller capacity to start with, it seems this battery in the 787 gets a far bigger work out.

Quoting RNAVFL350 (Reply 158):
Sure there was an incident during a test/certification flight (ZA002) which was beleived to be FOD

I sure would like to know what that "FOD" was...

Quoting aeroblogger (Reply 164):
There were issues with a UA aircraft's electrical system, which caused a divert to MSY. QR grounded an aircraft due to a similar issue. An Air India aircraft was grounded for a while because of issues with the airpacks, which turned out to be an electrical issue.

There is a clearly demonstrated pattern of electrical problems with this aircraft.

I really do wonder if there is a basic weakness with some of the basic parts within the whole electrical system, which manifests itself in different ways depending on the system it operates. Include the NH windshield too. Obviously, a system connected to a lithium battery is going to manifest itself in the most spectacular way of all the incidents. It would seem there is a faulty batch of batteries, which I did concur with as the facts seem to make that obvious, but I am not 100% sure.

Quoting Shenzhen (Reply 165):
Lets just hope that the FAA doesn't start grounding entire fleets when something happens that they can't explain (such as an airplane crashing into the ocean).
Quoting Shenzhen (Reply 182):
When the A330 went down, nobody knew why until sometime after the event. Why not ground the fleet, after all, safety is number one, no?

If another A330 went down within 10 days under the same circumstances - mysterious dive into the ocean with the same error messages relayed - it could well have been. It seemed quite possible it could have been severe weather related which no aircraft would have survived. However, you can see with two 787's on the ground to inspect with a toothcomb and obvious common failures, the FAA acted.

I have no doubt the 787 will be yet another amazing aircraft for Boeing like all its 7*7 predecessors and these incidents will just be stats on wiki in the future - I cant wait for AC to get theirs so I can add one to my log
Follow me on twitter for YVR movements @vernonYVR
 
XT6Wagon
Posts: 2726
Joined: Tue Feb 13, 2007 4:06 pm

RE: FAA Grounds 787 Part 4

Wed Jan 23, 2013 4:45 am

I'm saddened by the amount of trolling in these threads.

Do all these people avoid flying in highly flammable aluminum airliners? I mean its been used as rocket fuel so better not fly in an aluminum aircraft.

All the battery technologies have risk. Understanding and mitigating the specific risks is critical to safety. Lead acid like your car battery is mindblowingly unsafe when treated incorrectly. Overcharging for example causes high temps, hydrogen outgassing, swelling of the battery, leaking of acid, and possible explosions. So in this case we don't really reduce the risk by switching to lead acid, just change the nature of the problems.

Same with the transition from Piston to turbine engines. Turbine failures were quite nasty safety issues.... yet the industry embraced the possiblity of a hull loss due to this not due to economics, but rather the piston engines were massively less safe if less spectacular in the failure modes. They failed far more often, and liked to leak fuel and oil all over hot surfaces which made in flight fires not unheard of.

Fully on topic, while I agree with the grounding, I wouldn't hesitate to fly in a 787 this minute. We have clearly seen the redundancy works. The safety systems work. The FAA needs to find out what causes it as even though its safe as is, the airline industry hasn't gotten to be the safest form of transport by ignoring problems that are possible to correct.
 
SonomaFlyer
Posts: 2216
Joined: Tue Apr 20, 2010 2:47 pm

RE: FAA Grounds 787 Part 4

Wed Jan 23, 2013 4:47 am

Quoting cornutt (Reply 197):
Quoting AirframeAS (Reply 185):
As for the topic at hand, what is the target date to get the 787's back in the air? What's the earliest they can get?

Good question. Considering a fairly optimistic scenario... let's say that they determine tonight that the problem is a manufacturing problem with the batteries that failed, and that they are able to devise a battery test procedure that can be executed at airline maintenance facilities. I'd guess it would take two days minimum (of squadrons of people working around the clock) to prepare the necessary data to substantiate the safety case, and another two days of around-the-clock for the FAA to review and approve the data. During this time, the FAA allows airlines to ferry their planes back under some temporary flight restriction (e.g., batteries disconnected, APU started on ground power and remains running throughout the flight). So after four days, the airlines have an approved test procedure, and aircraft queued up. I have no clue how long it takes to remove the batteries from the aircraft using normal maintenance procedures; let's say that they can turn around one aircraft per day -- remove the batteries, test them, and reinstall them assuming they pass the test. So the earliest that a 787 could be put back into revenue service in this scenario would be Monday the 28th. After that, it would be one aircraft per day for each airline, less any aircraft that need their batteries replaced -- I don't know how many might be in stock, and any that are have to be tested too.

So the absolute minimum for getting all delivered 787s back into service appears to be about five weeks from when the solution is found. And that's assuming an awful lot of people are working day and night.


I don't think we have enough information to do anything but wildly guess. There are too many things we have to assume to make such a guess. The Japanese, with NTSB/FAA assistance are expanding their investigation of the battery manufacturer and adding a company (as yet unnamed in the UK to the list). They do seem to be focused at the moment on the battery but we can't assume this is the only area of inquiry.

I think its prudent to believe the grounding will last a couple more weeks at least. Given the step the FAA took, they will want to have all bases (and asses) covered on this one. That includes not just the battery but the charging system including hardware and software. That takes time to do properly.

I

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