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Unflug
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RE: FAA Grounds 787 Part 6

Mon Jan 28, 2013 8:43 am

Quoting vivekman2006 (Reply 37):
OMG No! Nowhere on this planet does the air temperature reach 100C (212F) Not even close!100C is the temperature at which water boils and is absolutely un-survivable! The highest temperature ever recorded on Earth is 56.7C (134F) in Death Valley, CA

I don't think that air temperature is relevant in this case, we are talking about limits for car batteries. I am quite sure that the inside of a black car in Death Valley can easily reach 100C.
 
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seahawk
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RE: FAA Grounds 787 Part 6

Mon Jan 28, 2013 8:51 am

Quoting JoeCanuck (Reply 47):
The FAA approved the containment...and for the most part, the containment did it's job; it prevented the spread of fire, significant damage from fire and significant damage from electrolyte. Obviously, some electrolyte did escape containment, and like with so many deficiencies in other aircraft, it was a scenario either never thought of or thought to be too unlikely to ever happen to be cause for concern.

Well, I would say the containment worked reasonably in the first incident, but failed in the second. Flammable liquids (or paste) must not escape the containment.

It is like the containment of any storage tank for flammable liquids. If the tank fails and burns and the material burns inside the containment, the safety design works. If the tank just releases the material and it escapes the containment, the safety design failed, even if the material never burned in that incident.

Just imagine having a type 2 incident (release of flammable liquids) followed by the ignition and fire of a type 1 incident and you got the potential risk that the FAA must consider. And from a pure technical point of view, each battery cell is one storage tank in this example, so a combination of both types of events seem possible as far as I can understand the problem.
 
Flyglobal
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RE: FAA Grounds 787 Part 6

Mon Jan 28, 2013 9:41 am

Quoting pliersinsight (Reply 24):
Are you taking battery compartment temps or air temp. I'm not so sure the air temperature reaches 100C (212F) in Death Valley. I've never been to India.....



To make thinks clear: we talk about a car which stays in the sun in 45°C for lets say 2-3 hs. It heats up quickly above the outside temperature. At least automotive has to design for 70-85°c. Its not only the batteries - also other car electronics have to work - engine management system, entertainment system under this conditions.

That's why batteries for car applications have extensive vent and even cooling ducts around the cells. I was surprised that the Dreamliner battery cells are just next to each other. I didn't expect it as extensive as in electric cars, but at least some!

Anyhow - hope they can get it wo work.
I am sure at Boeing - a Tesla/ Volt car like solution is part of an option discussed.

regards

Flyglobal
 
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rotating14
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RE: FAA Grounds 787 Part 6

Mon Jan 28, 2013 9:51 am

I was watching the news ticker and saw something close to the link below. Looks like the investigation is shifting from the battery itself and now to the monitoring system behind the battery. Personally I think its too soon to be moving away from the batteries. I vouch for others when I say that the batteries on the -8 need room the breathe and cool down.


http://www.salon.com/2013/01/28/boei...nitoring_system_maker/?mobile.html
 
XT6Wagon
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RE: FAA Grounds 787 Part 6

Mon Jan 28, 2013 10:19 am

Quoting KELPkid (Reply 40):
I just hope that when all is said and done, if the FAA's calls of the sky falling proves to be baseless, then someone makes those heads go rolling

To me the FAA has been reasonable. The grounding while largely fueled by Media Frenzy, does make cautionary sense until they get a handle on the common cause. (unlinked causes would be highly unlikely in events so close together, like two people in the same family winning the grand prize at two different lottos in the same week)

The NTSB on the other hand... Their statements blow my mind. To listen to them Boeing knowingly was selling firebombs to airlines and claiming they were fresh from the hands of God and all the perfection that implies. They seem to not understand basic things like the laws, regulations, special requirements, and in fact basic physics at times when they make statements about the 787.

Quoting seahawk (Reply 51):
Flammable liquids (or paste) must not escape the containment.

Please point out where it says that... Others have time and again pointed out it DOESN'T say that in the special requirements.

More to the point, you really need to define Flammable. You can put fires out with diesel fuel. You can power rockets with aluminum and iron. As far as I know we have never seen any definition of how the electrolyte reacts. We don't know its self ignition temp. We don't know if it can be burned at lower temps in the presence of a flame. If it can be burned quickly if converted to a mist or particulate stream is also unstated.

For all we know the flames escaping the containment vessel were other substances in the box contained in quanity. I'm assuming it has a fair bit of various insulating materials, all which likely burn well below the tempature of the battery in thermal runaway.

Also ignored by many calling for 100% containment, lets look at a recent viral video.
http://www.youtube.com/watch?v=ChCVfn9ePDc
you might note that there was NO combustion involved in this explosion. The tank reached a pressure at which it could not hold and then suffered complete failure. If you don't believe me, spend some research into boiler explosions. Many of the largest blasts in the 19th century outside of war were boiler explosions. Just a bit of water and heat would toss chunks of locomotives for miles.

So when you call for 100% containment you are asking for the intentional creation of a potential explosion. One in which many fairly vital electrical panels are located in relative close proximity. This would be thousands of times worse than a little burning electrolite getting sprayed onto the external metal covers. Which hasn't been shown to be possible much less probable during flight.
 
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Faro
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RE: FAA Grounds 787 Part 6

Mon Jan 28, 2013 11:06 am

Some new developments from Reuters:

http://www.reuters.com/article/2013/...mliner-japan-idUSBRE90R05C20130128

Quote:
Japan's government stepped in to give Boeing Co's now-grounded 787 Dreamliner and its made-in-Japan technology a boost in 2008 by easing safety regulations, fast-tracking the rollout of the groundbreaking jet for Japan's biggest airlines, according to records and participants in the process.
Quote:
There is no suggestion that easing regulatory standards contributed to the problems facing the Dreamliner, idled around the world after a string of malfunctions ranging from fuel leaks to battery meltdowns. There is also no evidence to suggest that continuing the mandate for more frequent manual inspections for new aircraft, including the Boeing 787, before 2008 would have helped catch signs of trouble earlier.

Difficult to see whether this will have any bearing on the duration of the grounding or not. Definitely not a favourable development for ANA and JAL though if the Japanese authorities feel they have to be more conservative than the FAA to cater to local public opinion.


Faro

[Edited 2013-01-28 04:12:14]
 
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seahawk
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RE: FAA Grounds 787 Part 6

Mon Jan 28, 2013 11:23 am

Quoting XT6Wagon (Reply 54):
So when you call for 100% containment you are asking for the intentional creation of a potential explosion. One in which many fairly vital electrical panels are located in relative close proximity. This would be thousands of times worse than a little burning electrolite getting sprayed onto the external metal covers. Which hasn't been shown to be possible much less probable during flight.

Please read my post correctly. I said flammable liquids, this does not mean 100% containment. I am fully aware that gases must be able to escape in an controlled manner, to avoid overpressure and possible damage from this. This is something I would consider standard safety design. Yet I think this failed in the second incident.
 
RickNRoll
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RE: FAA Grounds 787 Part 6

Mon Jan 28, 2013 11:43 am

Quoting XT6Wagon (Reply 54):
So when you call for 100% containment you are asking for the intentional creation of a potential explosion. One in which many fairly vital electrical panels are located in relative close proximity. This would be thousands of times worse than a little burning electrolite getting sprayed onto the external metal covers. Which hasn't been shown to be possible much less probable during flight.

Not if you can provide sufficient expansion for the solids, and an escape valve externally for the gases. The existing container was what you have described, although it does leak, but not in a controlled manner. Since it just depends on uncontrolled and unpredictable deformation of the lid, then there is no saying if fire and smoke can escape, or flammable liquids can spurt out. If it had not leaked, could it have exploded?

Have we had a final word yet on if flame escaped in the first incident.. I keep reading conflicting claims on that.
 
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PITingres
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RE: FAA Grounds 787 Part 6

Mon Jan 28, 2013 2:00 pm

Quoting seahawk (Reply 56):
I said flammable liquids, this does not mean 100% containment.

XT6Wagon's statement stands correct. There is no criteria for containment of liquids, flammable or not. The only criterion that matters is that the leakage not be able to hurt anything critical.

Even if you assume that the leaked electrolyte is flammable and burns, if there isn't much of it, it would not necessarily pose a hazard to the EE bay which must be designed to withstand a certain amount of damage.

Now, I'm not advocating that allowing the gunk to drip uncontained was a good idea. I rather think that the designers are wishing that they had added a drip tray or splash guard surrounding the primary containment. I'm just contradicting the notion that any electrolyte leakage is prohibited. It's the results that matter, not the leakage.
 
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7BOEING7
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RE: FAA Grounds 787 Part 6

Mon Jan 28, 2013 2:29 pm

Quoting Aesma (Reply 45):
You just made me think of something. You're talking about the venting of the battery itself, but what about the outflow valve ? If that gets blocked, then there is nowhere to go for the smoke except in the cabin/cockpit.

The forward overboard vent valve while not as large as the aft outflow valve is still large enough that blocking it would be difficult and is not in a position for large quantities of viscous material to find its way out of the airplane through it. The drain valves that run along the bottom of the airplane are closed by pressure shortly after takeoff, so I'm guessing a dedicated "drip/vent" line would be required.
 
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InsideMan
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RE: FAA Grounds 787 Part 6

Mon Jan 28, 2013 3:17 pm

don't know if this was posted earlier, interesting article....

http://www.huffingtonpost.com/2013/0...ive-japan-eased-saf_n_2564630.html
 
Kaiarahi
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RE: FAA Grounds 787 Part 6

Mon Jan 28, 2013 3:30 pm

Quoting tdscanuck (Reply 41):
I don't think it can ever be shown to be baseless...conservative, maybe, but it would be hard to argue they had *no* reason to be concerned.

Which does make me wonder how they'll react when a consumer device lets go in the cabin with serious damage. Of the 132 incidents documented so far by the FAA, it was just dumb luck in at least a dozen cases that there weren't serious consequences. Will they ban all devices on flights? Require the installation of a containment compartment into which pax must place all devices?
 
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Stitch
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RE: FAA Grounds 787 Part 6

Mon Jan 28, 2013 3:43 pm

Quoting beau222 (Reply 43):
Does the 748 series use the same type of battery or batteries that the 787 is having issues with?

No. I's probably NiCad (747s before the 747-400 use lead acid).
 
mham001
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RE: FAA Grounds 787 Part 6

Mon Jan 28, 2013 3:45 pm

Quoting rotating14 (Reply 53):
I vouch for others when I say that the batteries on the -8 need room the breathe and cool down.

I don't know about others but these batteries only get hot under heavy discharge/charge. The 787 batts don't see that much use by design. I do think however having the BMS in the same box is absurd. This would not have have happened were I in charge of that design.
 
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PITingres
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RE: FAA Grounds 787 Part 6

Mon Jan 28, 2013 4:41 pm

Quoting mham001 (Reply 63):
I do think however having the BMS in the same box is absurd. This would not have have happened were I in charge of that design.

Well, maybe. Trouble is that as soon as you take the management circuitry out of the box you have cabling and connectors to worry about, and they fail too. Plus it would be an added weight and expense. I'm sure that the engineering trade has to come down on the side of reliability even if other (non-battery) things fail, as opposed to preserving the BMS state if the battery poofs. Moving the BMS out of the box might be the right thing anyway, but I don't think it's quite the slam-dunk that you present it as. How about leaving it in the box and adding a little potting or thermal insulation around it?
 
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par13del
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RE: FAA Grounds 787 Part 6

Mon Jan 28, 2013 5:31 pm

Article on the BBC, now what.
http://www.bbc.co.uk/news/business-21230940
 
rolfen
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RE: FAA Grounds 787 Part 6

Mon Jan 28, 2013 5:40 pm

7 years to design the battery and they still couldn't get it right?
 
sankaps
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RE: FAA Grounds 787 Part 6

Mon Jan 28, 2013 5:55 pm

Excerpt from the Wall Street Journal today: "Shortly after the Federal Aviation Administration issued safety rules in 2007 for using lithium-ion batteries on Boeing Co.'s 787 Dreamliner jets, an industry standards-setting group called for stricter testing to prevent battery fires on aircraft.

Boeing and FAA officials decided that since design and testing of the plane was so far along, mandating the tougher standards would disrupt years of joint safety work and unfairly delay production of the cutting-edge Dreamliners, said people familiar with the details. "

Full article can be linked through http://thunderfeeds.com/reader/news/...-battery-tests-wall-street-journal



[Edited 2013-01-28 09:58:08]
 
spacecadet
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RE: FAA Grounds 787 Part 6

Mon Jan 28, 2013 6:00 pm

Quoting par13del (Reply 65):
Article on the BBC, now what.

Now they move on to looking at other parts of the electrical system, or to the design of the battery itself.

It does not mean they're at a dead end, as some others have suggested. It just means they appear to have ruled out the simplest potential cause: a faulty battery, or a "bad batch" of batteries.
 
frmrCapCadet
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RE: FAA Grounds 787 Part 6

Mon Jan 28, 2013 6:02 pm

There are reports coming out that that are clearing various parts and systems from fault, can one of the experts here tell us what this means. To an amateur the various reports look inconsistent.

Batteries OK
http://seattletimes.com/html/busines...2020230485_apasjapanboeing787.html

Charging system OK
http://seattletimes.com/html/nationw...230108_dreamlinerbattery28xml.html

This leaves the 'monitoring' system, but how could that cause a fault in a good battery and a good charging system? There are of course two different incidents and things may have failed in slightly different ways. EGADS! That real makes it hard.
 
asctty
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RE: FAA Grounds 787 Part 6

Mon Jan 28, 2013 6:11 pm

Quoting par13del (Reply 65):
Article on the BBC, now what.
http://www.bbc.co.uk/news/business-2...30940

Thank you, my specific post on this was deleted by the moderators.

Lithium Ion batteries are used all over complex industry sectors as part of Uninterrupted Power Supply (UPS) units, notably in my field submarines, with little or no significant defects. Indeed the main hazards are disposing of them safely at the end of a lifecycle. The battery monitoring systems are also very reliable and are usually supplied along with the battery by the manufacturer. These monitoring circuits relay information to the battery charging system, which may or may not be supplied by the battery OEM. In my experience the charging units supplied by the OEM are also very reliable, but there is evidence that non-OEM systems may not be so. Recent high profile laptop and car battery faults/recalls bear testament to this.
The question I ask therefore is who has supplied the charging equipment for the B787 batteries and did any failure studies of the charging equipment consider the effect on the battery itself?
If the Japanese investigation is found to be conclusive that the OEM battery is not at fault, then the investigation perhaps need to focus more toward somewhere else on the aircraft to identify the root cause.
 
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seahawk
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RE: FAA Grounds 787 Part 6

Mon Jan 28, 2013 6:15 pm

No obvious fault in the 2 major systems, this is not good.
 
SonomaFlyer
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RE: FAA Grounds 787 Part 6

Mon Jan 28, 2013 6:47 pm

The articles seem to rule out the battery and charging system. I am assuming they rule out any material defect in the assembly of the battery?

If the battery was not defective and the charging system is not defective, we should see this investigation broaden. This is of course problematic because it means the grounding would continue and the other systems (which presumably includes the software associated with these systems) are complex and reviewing code for debugging purposes takes time.

This is shaping up to be quite a mystery
 
rolfen
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RE: FAA Grounds 787 Part 6

Mon Jan 28, 2013 6:48 pm

Quoting frmrCapCadet (Reply 69):

There are reports coming out that that are clearing various parts and systems from fault, can one of the experts here tell us what this means. To an amateur the various reports look inconsistent.

I don't think any system can be "cleared" in the sense where it can be absolved from any responsibility. Electrical systems are complex and bugs can be hidden deep inside and appear randomly. It might also be a problem with a specific batch...

When working with complex systems you can never rule out a component before fully understading what happened!
 
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DocLightning
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RE: FAA Grounds 787 Part 6

Mon Jan 28, 2013 6:58 pm

Quoting SonomaFlyer (Reply 72):

This is shaping up to be quite a mystery

It is, and if it turns out that the explanation is "statistical aberration," then it will take many hundreds of thousands of event-free flying hours to demonstrate that.

The failure to find a consistent cause is very disturbing and indicates that this grounding may be quite prolonged.
 
Kaiarahi
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RE: FAA Grounds 787 Part 6

Mon Jan 28, 2013 7:04 pm

Before everyone concludes that 2+2=22, what the NTSB actually said was that it found no obvious anomalies in the undamaged JL battery (i.e. the forward bay battery). The NTSB said in last Thursday's briefing that the failed (APU) battery showed evidence of a short circuit (hole caused by an electrode). There are photos on the NTSB website. They are still "deconstructing" the failed battery.

They have also found no significant anomalies in the charging unit made by Securaplane (that's the unit that took 7 years to design and develop - no one has said that the battery took 7 years).

So far, they've also said that the circuit boards for the battery monitoring system (apparently made by Kanto) were too degraded to provide useful information.
 
rheinwaldner
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RE: FAA Grounds 787 Part 6

Mon Jan 28, 2013 7:51 pm

Quoting seahawk (Reply 9):
yet they still use an active cooling and heating system to control the individual battery packs

Lipos don't like cold temperatures. They loose a lot of capacity. Thus the real RC nerds heat them to 40°C before flying in Winter. That's for sure the reason why Tesla heats in some cases their lipos...

Quoting Kaiarahi (Reply 32):
generally

The issue is that the 787 is not grounded because of things that happen generally. Generally you are correct. Generally the 787 would not have been grounded. If it'd have behaved generally...

I repeat that it is not rocket science to charge and treat lipos in a way that they never start burning. Especially in such a highly professional environment and error-prone application. The NTSB and the FAA are right in demanding that the cells never get heated up unsafely. Because it is possible to build a system like that. The point is that the existing design fails to meet that requirement and that the reason is unknown. Thats all.
 
ComeAndGo
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RE: FAA Grounds 787 Part 6

Mon Jan 28, 2013 8:03 pm

Quoting Kaiarahi (Reply 61):
Which does make me wonder how they'll react when a consumer device lets go in the cabin with serious damage.

it already happened, the airlines will ban Li-Ion's from flight. Virgin Atlantic did so a few years ago.
 
Unflug
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RE: FAA Grounds 787 Part 6

Mon Jan 28, 2013 8:25 pm

Quoting ComeAndGo (Reply 77):
it already happened, the airlines will ban Li-Ion's from flight.

No more cell phones, cameras, tablets and notebooks in the cabin? That will be kind of hard to enforce.
 
ba319-131
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RE: FAA Grounds 787 Part 6

Mon Jan 28, 2013 8:44 pm

Well, if the batteries have found to be 'clear' for duty, this seems to fall back to the electrical system in general. Given the huge amount of electrical cabling etc in this plane, the grounding could well be a long drawn out process, something Boeing nor the airlines can really afford.

This is turning into a true nightmare for everybody linked in whatever way to the 787 program.

Thankfully both of my 787 intercontinental flights went without issue, however with the publicity this ground has been getting will certainly eat into the Dreamliners 'halo' effect.

I hope Airbus are watching this closely and learning as much as they can, the A350 can ill afford similar delays and problems.

Quoting Unflug (Reply 78):

- Agreed, just not possible to enforce.
 
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scbriml
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RE: FAA Grounds 787 Part 6

Mon Jan 28, 2013 8:44 pm

Quoting ComeAndGo (Reply 77):
Virgin Atlantic did so a few years ago.

That was a short-term issue related to two specific brands of laptop - Dell and Apple had a massive battery recall in 2006 after several battery fires. The laptops weren't banned but customers were asked to remover the batteries before take-off and could only use the device if their seat had a power source.

VS certainly doesn't ban batteries now.   
 
ComeAndGo
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RE: FAA Grounds 787 Part 6

Mon Jan 28, 2013 9:01 pm

According to the NTSB slide presentation each battery cell has a Rupture Valve. Where does the electrolyte go to if it escapes through that valve. And if the electrolyte is conductive does it not pose a problem for the exposed cell terminals on top of each battery cell?
 
tdscanuck
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RE: FAA Grounds 787 Part 6

Mon Jan 28, 2013 9:13 pm

Quoting packsonflight (Reply 42):
As I understand this, the special condition say that battery fire should contained and not pose a danger to other system, and this goes for the whole flight envelope with no exceptions.

The "exception" is the "extremely remote" stipulation...the FAA didn't require 100% protection, as they do for any single failure, but allow a (very small) probability of multiple things lining up. I don't see why turbulence wouldn't enter into that fault tree, as they do with lightning.

Quoting beau222 (Reply 43):
Does the 748 series use the same type of battery or batteries that the 787 is having issues with?

Different.

Quoting Aesma (Reply 45):
You just made me think of something. You're talking about the venting of the battery itself, but what about the outflow valve ? If that gets blocked, then there is nowhere to go for the smoke except in the cabin/cockpit.

There's another outflow valve (forward bilge) and overpressure relief valves (just below the main deck floor). The outflow valves are also large...it would take an extremely big piece of debris to fully block them.

Quoting cornutt (Reply 46):
Although if the outflow valve was completely blocked, I think the whole aircraft would quickly be in trouble with over-pressurization. I assume there are over-pressure relief valves, but I have no idea where in the aircraft they might be.

They're on the left side forward, I believe, just below the main deck floor.

Quoting seahawk (Reply 51):
Well, I would say the containment worked reasonably in the first incident, but failed in the second. Flammable liquids (or paste) must not escape the containment.

That's *not* a requirement of the special condition. In fact, by the way the special condition is written, it's explicitly allowed.

Quoting seahawk (Reply 51):
It is like the containment of any storage tank for flammable liquids. If the tank fails and burns and the material burns inside the containment, the safety design works. If the tank just releases the material and it escapes the containment, the safety design failed, even if the material never burned in that incident.

The object is to make sure any release is harmless. Normal flammability containment isn't pressure tight, it has to vent something or it needs to be built as a pressure vessel.

Quoting mham001 (Reply 63):
I do think however having the BMS in the same box is absurd. This would not have have happened were I in charge of that design.

The farther you move the BMS from the battery, the more potential failure points you inject into the fault tree. Given the extremely tight requirements the FAA put on the BMS, integration with the battery was probably, by far, the most reliable available option. The fact that the BMS was destroyed in the fire isn't that significant, since once a thermal runaway begins the BMS can't do anything about it anyway, it's too late.

Quoting sankaps (Reply 67):
Boeing and FAA officials decided that since design and testing of the plane was so far along, mandating the tougher standards would disrupt years of joint safety work and unfairly delay production of the cutting-edge Dreamliners, said people familiar with the details.

Before everybody freaks out, note that this is how virtually all certification is done. They freeze the certification basis at a point in time (usually when the OEM notifies the regulatory that they're pursuing a new or amended TC) and agree to hold it there for a fixed period (usually 5 years) so that the OEM's have some design stability. Changes in the interim are assessed against the certification basis and they only roll in new requirements if they believe there's a really compelling need to do so. In this case, the FAA had no reason to think the existing standards weren't tough enough.

Tom.
 
asctty
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RE: FAA Grounds 787 Part 6

Mon Jan 28, 2013 9:16 pm

Quoting ComeAndGo (Reply 81):
According to the NTSB slide presentation each battery cell has a Rupture Valve. Where does the electrolyte go to if it escapes through that valve. And if the electrolyte is conductive does it not pose a problem for the exposed cell terminals on top of each battery cell?

The point here is that that batteries are OK if the control system works. Who owns the control system? The battery manufacturer specifies safe parameters for it to be operated within, If is is connected to a system that does not maintain these parameters then failure may result.

In the general hierarchy of risk reduction; Eliminate, Reduce, Isolate or Contain, where released electrolyte ends up and containing it is way down the list as the likelihood of a release should be engineered out. Don't forget that if the Rupture Valve is activated then the battery is now useless in its function as a safety supply to the aircraft electrical system. Now that is really important is it not? It appears that the Japanese authorities have found no manufacturing reason for the batteries to fail. So where does the fault reside? Surely it must be upstream/downstream of the battery depending if it is on charge or load.

I have stated before that these batteries reside safely in many safety critical system UPS's with a very high reliability, else they would be approved for such applications.
 
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Francoflier
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RE: FAA Grounds 787 Part 6

Mon Jan 28, 2013 9:46 pm

Quoting Unflug (Reply 78):
No more cell phones, cameras, tablets and notebooks in the cabin

The ban concerns checked luggage, freight, anything that is not accessible in flight.

Let's not forget that Li-ion batteries have already downed an aircraft once.
 
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7BOEING7
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RE: FAA Grounds 787 Part 6

Mon Jan 28, 2013 10:00 pm

Quoting tdscanuck (Reply 82):
Quoting Aesma (Reply 45):You just made me think of something. You're talking about the venting of the battery itself, but what about the outflow valve ? If that gets blocked, then there is nowhere to go for the smoke except in the cabin/cockpit.
There's another outflow valve (forward bilge) and overpressure relief valves (just below the main deck floor). The outflow valves are also large...it would take an extremely big piece of debris to fully block them.

Quoting cornutt (Reply 46): Although if the outflow valve was completely blocked, I think the whole aircraft would quickly be in trouble with over-pressurization. I assume there are over-pressure relief valves, but I have no idea where in the aircraft they might be.
They're on the left side forward, I believe, just below the main deck floor.

If there is smoke in the fwd equipment area the fwd vent valve opens to clear the smoke overbd. It is a several inch hole in the airplane and it would be impossible for a glob of goo to find its way there let along block it. That's the valve with the black stuff in the ANA photo. The fwd outflow valve is bigger but generally almost closed during normal flight to pressurize the airplane. The bilge (water, goo whatever) goes out the drain valves which run along the keel beam at the bottom of the fuselage and are only open below 2+/- psi--so through out most of the flight they are closed--these could be blocked but that's not a big deal. For the positive pressure (over pressure) relief valves to open you'd have pressurize the airplane above its max limit which would mean both outflow valves (fwd & aft) would have to be closed and the fwd vent valve would have to be closed.
 
asctty
Posts: 144
Joined: Sat Dec 13, 2008 5:23 am

RE: FAA Grounds 787 Part 6

Mon Jan 28, 2013 10:12 pm

Quoting 7BOEING7 (Reply 85):
If there is smoke in the fwd equipment area the fwd vent valve opens to clear the smoke overbd. It is a several inch hole in the airplane and it would be impossible for a glob of goo to find its way there let along block it. That's the valve with the black stuff in the ANA photo. The fwd outflow valve is bigger but generally almost closed during normal flight to pressurize the airplane. The bilge (water, goo whatever) goes out the drain valves which run along the keel beam at the bottom of the fuselage and are only open below 2+/- psi--so through out most of the flight they are closed--these could be blocked but that's not a big deal. For the positive pressure (over pressure) relief valves to open you'd have pressurize the airplane above its max limit which would mean both outflow valves (fwd & aft) would have to be closed and the fwd vent valve would have to be closed

This is locking the door after the horse has bolted in safety terms as it will not prevent the battery overhating in the first place. A very complex suggestion as to how to deal with a battery that has potentially not been operated correctly thereby presenting a hazard to the aircraft. What if the battery was called upon to supply emergency power and permit safe landing of the aircraft?

Please reassure me this is not the normal hazard assessment approach in the airline industry?
 
Michiganatc
Posts: 145
Joined: Fri Nov 28, 2008 3:34 pm

RE: FAA Grounds 787 Part 6

Mon Jan 28, 2013 10:18 pm

Forgive me if this was already talked about, I haven't had a chance to read through the 750+ posts  

With the 787's all grounded, what airports did United's end up at? I'm hoping to see 1 or 2 at the United hangars next week.

Thanks!
 
AeroWesty
Posts: 19551
Joined: Sat Oct 30, 2004 7:37 am

RE: FAA Grounds 787 Part 6

Mon Jan 28, 2013 10:30 pm

Quoting michiganatc (Reply 87):
With the 787's all grounded, what airports did United's end up at?

Location/plane number:

IAH: 901, 902, 905 & 906
LAX: 903
NRT: 904
 
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7BOEING7
Posts: 3039
Joined: Fri Oct 12, 2012 5:28 pm

RE: FAA Grounds 787 Part 6

Mon Jan 28, 2013 11:16 pm

Quoting asctty (Reply 86):

This is locking the door after the horse has bolted in safety terms as it will not prevent the battery overhating in the first place. A very complex suggestion as to how to deal with a battery that has potentially not been operated correctly thereby presenting a hazard to the aircraft. What if the battery was called upon to supply emergency power and permit safe landing of the aircraft?

Please reassure me this is not the normal hazard assessment approach in the airline industry?


All I was describing was the present way all the various "holes" in the airplane operate and the fact that the battery spreading goo around probably wouldn't block any of them or cause an overpressure event. It wasn't a battery design safety discussion.
 
justloveplanes
Posts: 1014
Joined: Thu Jul 08, 2004 5:38 am

RE: FAA Grounds 787 Part 6

Mon Jan 28, 2013 11:23 pm

Quoting francoflier (Reply 84):
Let's not forget that Li-ion batteries have already downed an aircraft once.

If you are referring to the UPS 747, I think that was an entire pallet of Li Ion batteries. A huge amount of stored energy and a potential fireball. The ANA flight by comparison burned through the main on board battery completely, in flight, with no ill effects save for some sludge in the forward bay and smell.

BTW, If the containment had been "a little bit" better to start with, I don't think any of this grounding would have happened. Two failed components. This would be treated as a reliability issue and not a hazard, there is only so much energy in these things and you can design safe containment without any rocket science. There are much more stringent containment solutions used in much more hazardous environments (refineries, oil rigs and other, explosive, high heat and high vibration environments) that are in widespread use. This is not a problem without a ready solution, lots of proven know how for this type thing.

I believe the NTSB, JAA and others should approach this from a two step process:

Update the containment (straightforward, maybe a bit time consuming, but straightforward and predictable)
Re-examine the problem from a loss of system redundancy point of view for flight safety vice a flight hazard and then conclude grounding or AD.

[Edited 2013-01-28 15:26:03]
 
rwessel
Posts: 2448
Joined: Tue Jan 16, 2007 3:47 pm

RE: FAA Grounds 787 Part 6

Mon Jan 28, 2013 11:35 pm

Quoting ComeAndGo (Reply 81):
According to the NTSB slide presentation each battery cell has a Rupture Valve. Where does the electrolyte go to if it escapes through that valve.

Into the empty space in the battery case. And if enough boils out of the cells, obviously out the battery case vents and onto the floor of the EE bay. The scope of the latter may be one of the issues the FAA and NTSB are having.

Quoting ComeAndGo (Reply 81):
And if the electrolyte is conductive does it not pose a problem for the exposed cell terminals on top of each battery cell?

Doesn't matter, the battery is dead/dying/self-destructing at that point anyway. The rupture values are there to prevent a pressure buildup that would lead to an explosive rupture.
 
RickNRoll
Posts: 1878
Joined: Fri Jan 06, 2012 9:30 am

RE: FAA Grounds 787 Part 6

Mon Jan 28, 2013 11:37 pm

Quoting JoeCanuck (Reply 47):
The FAA approved the containment...and for the most part, the containment did it's job; it prevented the spread of fire, significant damage from fire and significant damage from electrolyte. Obviously, some electrolyte did escape containment, and like with so many deficiencies in other aircraft, it was a scenario either never thought of or thought to be too unlikely to ever happen to be cause for concern.To solve that particular problem, they build a more robust container...perhaps double or triple walled with expansion space and dedicated venting. That obviously doesn't solve the battery problems, but it would take care of the containment.

That's one problem.

According to the FAA "The battery failures resulted in release of flammable electrolytes, heat damage, and smoke on two Model 787 airplanes."

However, there is no controlled means of releasing pressure in the existing design. The case is sealed, until pressure forces it to deform, allowing flammable material to be released. It allows heat damage to occur to surrounding equipment, so the case is not protecting the environment adequately either, in respect to the heat generated by a thermal runaway.

The enhanced case is obviously the answer, but what would this require in respect of design, manufacturing, testing and certification? How long would this process take? Would the FAA keep the 787 grounded till this whole process is complete.
 
AeroWesty
Posts: 19551
Joined: Sat Oct 30, 2004 7:37 am

RE: FAA Grounds 787 Part 6

Mon Jan 28, 2013 11:44 pm

Idle question: Other than just looking at the photo of the EE bay from the JAL plane, has there been any indication what other than the battery pack was damaged, and how long it would take to repair the ancillary damage the plane sustained?
 
RickNRoll
Posts: 1878
Joined: Fri Jan 06, 2012 9:30 am

RE: FAA Grounds 787 Part 6

Tue Jan 29, 2013 12:09 am

Another question. Wouldn't Boeing have had to do a battery failure containment test during certification. Given the design of the container, I would assume it would have behaved pretty much the same then as it did in the recent events. Would it not have had flammable electrolyte leaking out in those tests, and have generated the same amount of heat. Why would that have been acceptable then, but not now?
 
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Stitch
Posts: 27645
Joined: Wed Jul 06, 2005 4:26 am

RE: FAA Grounds 787 Part 6

Tue Jan 29, 2013 12:19 am

Quoting RickNRoll (Reply 94):
Another question. Wouldn't Boeing have had to do a battery failure containment test during certification. Given the design of the container, I would assume it would have behaved pretty much the same then as it did in the recent events. Would it not have had flammable electrolyte leaking out in those tests, and have generated the same amount of heat. Why would that have been acceptable then, but not now?
BECAUSE THE SPECIAL CONDITIONS DO ALLOW THE CONTAINMENT VESSEL TO LEAK ELECTROLYTES.

If it did not, it risks explosion. That is why the top of the container has a handful of screws holding it on and it overlaps the sides of the case so it can vent electrolyte. If it was designed to not allow a leak, they would have welded the top shut, as well.

What is NOT allowed to happen is that the leaked electrolytes subsequently take out a flight-critical system. And while JA804A didn't suffer damage to critical systems from the electrolyte, the FAA and NTSB are not convinced that it cannot happen.
 
RickNRoll
Posts: 1878
Joined: Fri Jan 06, 2012 9:30 am

RE: FAA Grounds 787 Part 6

Tue Jan 29, 2013 12:30 am

Which does not answer the question. If the events now would have been pretty well identical to the tests then, why is it different now?
 
spacecadet
Posts: 3584
Joined: Thu Sep 20, 2001 3:36 am

RE: FAA Grounds 787 Part 6

Tue Jan 29, 2013 12:34 am

Quoting justloveplanes (Reply 90):
Update the containment (straightforward, maybe a bit time consuming, but straightforward and predictable)
Re-examine the problem from a loss of system redundancy point of view for flight safety vice a flight hazard and then conclude grounding or AD.

The NTSB has made it clear that they're not going to accept fires on airliners, period. As various people have said, there's always going to be that chance, however remote and with any kind of battery, so you're never going to make it impossible. But the NTSB's problem here is that the fire happened on the JAL flight, and then a week later something similar happened on an ANA flight. The only way you're going to satisfy the NTSB is to make the frequency of such events much, much less than that.

In other words, updating containment and re-examining redundancy are not going to solve the issue from the NTSB's perspective. What's going to solve the issue is making the problem occur with far lesser frequency. That means finding the root cause and fixing it.

The FAA could always go against the NTSB's recommendations and remove or revise the AD, and there's a chance that they might do that if things drag on for an indeterminate amount of time, but that would probably be a foolish PR move because they'd basically be telling people "we know we said we were grounding the plane for safety reasons, but... well, yeah, just go fly it anyway."

Think about it - that wouldn't be good for anyone, including Boeing or the airlines who fly the plane. In fact, it would put the airlines in a pretty terrible position.

[Edited 2013-01-28 16:36:56]
 
ComeAndGo
Posts: 815
Joined: Thu Mar 31, 2005 5:58 pm

RE: FAA Grounds 787 Part 6

Tue Jan 29, 2013 12:42 am

Quoting rwessel (Reply 91):
Doesn't matter, the battery is dead/dying/self-destructing at that point anyway.

Right, but if one cell is dying and the others are fine the potential short circuit could contribute to more doom, fireworks and fire. And there is no space on the side of the cell with the rupture valve. According to the slide in the NTSB presentation the two ports are next to the battery casing on one side and next to the adjacent cell on the other side. There's no empty space. The empty space is were the charging circuit board is at and on top of the battery where the terminals are at. This battery is crammed together like a sandwich.
 
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Stitch
Posts: 27645
Joined: Wed Jul 06, 2005 4:26 am

RE: FAA Grounds 787 Part 6

Tue Jan 29, 2013 12:44 am

Quoting RickNRoll (Reply 96):
Which does not answer the question. If the events now would have been pretty well identical to the tests then, why is it different now?

That I would like to know, myself.   

JA804A operated for a year without a problem. 10 months with one battery and 3 months with another. And NH has three birds between 12 and 17 months with no issues.

And yet JA829J operated some two weeks before it had a problem. But JL has other birds going on 9+ months with no issues.

To my mind, something has to have changed. Some new variable has been introduced that significantly altered the probabilities of a battery issue. I've heard third-hand of a software update being applied to some 787s, but to date nobody else has picked it up so I don't know if there is any truth to it.

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