Please carry on discussion here.

Previous thread located here: FAA Grounds 787 Part 5 (by iowaman Jan 23 2013 in Civil Aviation)#1

NZ1
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DocLighting writes:
" If there is, say, severe turbulence, it could navigate around the compartment that way."

Doc, you've taken blood samples - they're thinner than the electrolyte goo you're talking about. This stuff is not magically sticky in a picture and later capable of gymnastics in turbulence.

Also, just how turbulent are you talking about?

I don't see ANY liquid which is already stuck to something changing its direction in a major way with, say, a 2g event. I suspect that we'd have other issues to worry about at that point.

And, frankly, positing a battery meltdown followed by severe turbulence is something best left to Hollywood.

Really and truly, these situations just don't line up like that. Outside of Hollywood, that is.

Cheers!

Has John Leahy made a comment at all about the grounding and how it may affect the A350 program?

Some of the comments in the previous thread before it was locked are unbelievable!

"When has the FAA or NTSB ever been proactive?"

Well -- they are being proactive right now! Grounding the battery system and thereby the aircraft until they can be sure the root cause issues are identified and fied, before something disastrous occurs.

"It is all just politics".

In other words, Obama is to blame. Right. Boeing is based primarily in two states which helped Obama get re-elected -- Washington and Illinois. But Obama wants to screw them?

Guys -- we need to take a step back, read the NTSB statement, and just calm down and accept that the grounding wasa prudent, proactive step given the two incidents just 9 days apart, involving a new system and technology that had only recently been certified but hadn't really stood the test of time and extensive usage yet. That is exactly the right thing they did. And I love Boeing and its products as much as anyone else.

Quoting RottenRay (Reply 1): And, frankly, positing a battery meltdown followed by severe turbulence is something best left to Hollywood.

Murphy's Law. And aviation probably supplies one of the best (or worst) examples of same with the KLM/Pan Am collision at Tenerife in 1977: a bomb had exploded earlier at Las Palmas and the aircraft were diverted to Tenerife. Then you had the fog, the absence of ground radar, the misheard ATC instructions and the blocked-off taxiway. Had one of those events not occurred there would have been no collision.

Quoting RottenRay (Reply 1): Really and truly, these situations just don't line up like that. Outside of Hollywood, that is.

Unfortunately reality offers sometimes more phantasy than hollywood. Take almost any air crash investigation and you will find situations have lined up in ways not to be expected...

Quoting RottenRay (Reply 1): Doc, you've taken blood samples - they're thinner than the electrolyte goo you're talking about. This stuff is not magically sticky in a picture and later capable of gymnastics in turbulence.

Do you know the consistency of this material over all temperature ranges? If so, how do you know? Also, blood is not terribly viscous and it gets all over everything. Are you saying this stuff is like blood?

Quoting Braybuddy (Reply 4): Murphy's Law. And aviation probably supplies one of the best (or worst) examples of same with the KLM/Pan Am collision at Tenerife in 1977: a bomb had exploded earlier at Las Palmas and the aircraft were diverted to Tenerife

Yup. Just about every major aviation disaster in history has occurred because of an unlikely chain of events all coinciding (leaving aside intentional sabotage).

Quoting liftsifter (Reply 2): Has John Leahy made a comment at all about the grounding and how it may affect the A350 program?

Even Mr. Leahy is smart enough to know to keep his mouth shut.

Anyway, it is far too early in the investigation to determine whether Airbus will actually need to make changes to the design of the A350, but you can rest assured that some people at TLS are watching these proceedings with great interest. And you can rest assured that none of them are gloating about it, because they know that if they are not careful, their new A350 might be next.

First, I'd like to thank once again CM, tdscanuck, rcair1 and others for informative posts. I would also like to welcome b2319 to a.net, your post certainly got me thinking about containment and relief valves as far more complex beasts than I had thought before. Thanks.

Second, I have a plea that this thread would not descent into political speculation or accusing NSTB or FAA of misbehaviour. They are one of the most respected organizations in the world in this area, and it would be, IMO, unthinkable that they would be misbehaving any way. They are the true experts. They have all the information that we do not have here in a.net. Exact state of containment systems and other equipment in the bays, for instance. If they say they need to ground the plane, they have a reason to do so. Even if it is just not being certain that no other damage occurs in some (perhaps obscure) other scenario than the one played out in the two incidents. Let them do their work.

And now to the topic of my post. I'm trying to understand different scenarios for lifting the grounding.

Scenario 1: Operational changes

ETOPS limitations, in-the-ground inspections, lower thresholds for diversion, perhaps some battery usage/charging changes in flight. If these procedures would be sufficient, the grounding could have been over in days. I can only conclude that either these procedures are insufficient, or that the NTSB does not understand the events well enough to allow the grounding to be lifted yet. Obviously, the root causes need to be found.

Scenario 2: Battery manufacturing quality

A problem is discovered in battery batches and/or manufacturing process, the issue is fixed and the planes start to fly again. If this was the solution, we could see the end of the grounding in weeks, particularly if defective batteries can be found by testing.

I think this is somewhat unlikely as the only fix, as I suspect the NTSB wants to understand how well the containment works in the eventual cases that even with high-quality batteries, there can be a thermal runway in one of them some day.

Scenario 3: Battery charging systems

Or perhaps these systems misbehaved in some way. A fix to them would be an engineering (and re-certification) process. In the best case this would take a few months, in the worst case more. I remember that the battery system manufacturer took seven years to design the current batteries. In my opinion, that is a very long time, and changing a component should be possible in months.

Charging system issues is a possible root cause, but it is looking a bit unlikely perhaps, if the early reports are true that the batteries were not overcharged. That being said, if the per-cell history of events burned down with the batteries, how would we know?

Scenario 4: Containment structures

It is probably not sufficient to fix the containment structures, but if a battery manufacturing fault is found, fixed, and the containment is enhanced to make the NTSB/FAA confident that it works in all cases, then the plane cloud clearly fly.

It is difficult to estimate how long this would take. A steel plate "shower curtain" would be very easy to add. Certification, analysis that it works in all cases would probably take longer. I'd say months.

A more significant modification, such as fluid venting out of the aircraft or even enlarging or moving the battery containment structure could take much longer. Half a year for venting out, years for moving the structure or making the EE bay larger to fit the new containment structure. FWIW, I think the shower curtain is probably going to be sufficient.

Scenario 5: Electrical system

Or maybe there is some issue with the electrical system that is causing trouble for the batteries. If this is the case, it would be very difficult and time-consuming to understand and fix the issues. But as an engineer, I find it difficult to believe this to be the case. Surely the design has voltage and current regulators that isolate the quality of the aircraft electricity from the quality of the electricity fed to the batteries.

But if they need to do something with the electrical system, it could take years. Adding a more high-quality regulation circuitry could be easy, however, maybe only months.

Conclusions

I think the issues are somewhere in categories 2 through 4. If a battery or charging system fault can be identified and a slightly enhanced containment put into place, the plane should fly in 4-6 months, if not sooner, at least as a temporary measure for current frames. And a more intelligent new containment adopted for future frames.

But it is also possible that once the events are understood, the current containment system is deemed adequate (as tdscanuck and CM believed early on in this thread). Then the critical time factor is understanding why the batteries failed, and I'd predict that to take some number of months anyway.

In the other extreme, it is also possible that the containment system needs a significant change. If no intermediate solution can be found, this could drag on for over a year. (Interestingly, according to Wikipedia, A350 should enter service mid 2014. If the worst comes to worst, we could see the 350 fly commercially before the 787 is back in the air. But I do not believe this to happen.)

Finally, I should add that none of this is rocket science. Batteries and charging systems are well understood. And the energy levels for containment are still... small, when you consider the size and energy content of the device. It is some number of times bigger than a car battery, not a nuclear bomb. Boeing engineers know how to enhance it, if it needs enhancing.

[Edited 2013-01-27 01:03:37]

Just maybe we will have to accept that lion batteries will catch fire, on any airplane that uses them. It will be up to the containment to be able to handle any fire. Or just ban the use of lion in air craft all together. Someone needs to develop a JET-A fueled fuel cell quickly..

Looking at the Tesla Roadster electric car for example, I find it interesting that the individual cells are so small in their design, yet they still use an active cooling and heating system to control the individual battery packs. Even the space between each cell seems much larger in relation to the cell size, than in the Boeing solution:

I know it is a little of topic but interesting: http://www.teslamotorsclub.com/showt...hp/3810-Roadster-battery-%28ESS%29

Quoting B2319 (Reply 260): I joined a.net because, in part 3 of this thread, someone said the electrolyte "wasn't a liquid, it was a paste". What an absolutely ill-informed post if there ever was one. Anyway, the physical properties of the material to be vented will play a vital part of the safe handling of the release. Some examples of physical properties are density, viscosity, possibly solids content and so on.

How totally incorrect and ill informed the above post is. With out revealing too much information, the paste statement was relayed to us by the manufacturers, you can figure that out for yourself if you'd like, not just a statement put out there by a anet member. But if someone knows more than Boeing and Thales, be my guest, go ahead and post your information. This is why folks are bailing on this thread.

Quoting CALTECH (Reply 11): How totally incorrect and ill informed the above post is. With out revealing too much information, the paste statement was relayed to us by the manufacturers, you can figure that out for yourself if you'd like, not just a statement put out there by a anet member. But if someone knows more than Boeing and Thales, be my guest, go ahead and post your information. This is why folks are bailing on this thread.

I'm bailing too. You can pick up a copy of any physical chemistry textbook and try and understand my point. (I studied using Atkins, though there were others). The scientific terms for the three phases are solids, liquids and gases. Sometimes vapours and gases are interchangable, in some contexts.

From memory, the post was a claim that a paste was somewhat not a liquid or didn't posses a liquid component. In any case, there weren't any links supplied for me to consider the original source.

If you've the ability to determine that my criticism of scientifically-incorrect statements, independent of the source, albeit non-referenced, originated with yourself, well, that's impressive.

My GBP 15.40 experiment with a.net, has been exactly that- an experiment.

I'm bailing from both the thread, and the forum, and have no plans to contribute, nor lurk, again.

With thanks and regards

B-2319.

Assuming (a) the cause of the overheating problem were identified (b) a fix had been designed, built and tested to a level where it would be acceptable to FAA (c) a fix for the containment issue had been designed, built and tested to a level where it would be acceptable to FAA, how long would it take the FAA to certify the aircraft as being safe again?

Once the aircraft were certified as safe, how long would it take to put the revised components into production and start installing them on the 787's delivered so far?

Would it be a few weeks between a solution to the problems being found and installation starting? Several (2/3/4) months?

Anyone have any idea how long the aicraft delivered will remain on the ground after a remedy is devised and approved?

Quoting b2319 (Reply 12): I'm bailing too. You can pick up a copy of any physical chemistry textbook and try and understand my point. (I studied using Atkins, though there were others). The scientific terms for the three phases are solids, liquids and gases. Sometimes vapours and gases are interchangable, in some contexts.

So what you know is learned from a book. Interesting.

Quoting b2319 (Reply 12): From memory, the post was a claim that a paste was somewhat not a liquid or didn't posses a liquid component. In any case, there weren't any links supplied for me to consider the original source.

The memory point is incorrect and way off the mark. No where was it stated that it was not a liquid or didn't posess a liquid component, that has been inserted from a fallible memory. There were no links, it is what has been said by those who work with the batteries. Boeing is where the info comes from. Again, if you have info that shows Boeing has it wrong, please by all means please post it.

Quoting b2319 (Reply 12): If you've the ability to determine that my criticism of scientifically-incorrect statements, independent of the source, albeit non-referenced, originated with yourself, well, that's impressive.

Think It was my post that first brought up that the electrolyte is more of a paste than a liquid such as those found in lead acid batteries. A incorrect post #260 was made in the last thread #5, that was impressive, ' I joined a.net because, in part 3 of this thread, someone said the electrolyte "wasn't a liquid, it was a paste". What an absolutely ill-informed post if there ever was one. '

So excuse me if there is a issue with your "absolutely ill-informed post."

Quoting sweair (Reply 8): Someone needs to develop a JET-A fueled fuel cell quickly..

It's called an APU sweair

Quoting LN-KGL (Reply 18):

A fuel cell is a bit kinder to the environment than the APU as that is a small jet turbine itself. A fuel cell can use multiple fuels and create less pollution and noise. Maybe the cost and the heat is a problem?

Quoting seahawk (Reply 10): Looking at the Tesla Roadster electric car for example, I find it interesting that the individual cells are so small in their design, yet they still use an active cooling and heating system to control the individual battery packs. Even the space between each cell seems much larger in relation to the cell size, than in the Boeing solution: I know it is a little of topic but interesting: http://www.teslamotorsclub.com/showt...SS%29

And so will be other LI Car battery systems, like the Chevy Volt and newer Toyota's. Automotive use requires you to have your batteries at Winter in Canada and Russia (-40°C) and also at 100°C at least for heat (Death Valley, India, to name some location).
This requires heating devices and also ventilation and cooling ducts for the batteries.

For Air Planes the design requirements are different - less environmental temperature span at the battery location.

In one of the earlier threads I mentioned that I know that for Chevy it took rather 1/3rd effort for the Cell development and selection its self, 1/3rd for the packaging of the cells and 1/3rd for Power electrics and especially micro controls, software and data calibration.

For Automotive all is about warranty offer. A Chevy, a Toyota and probably as well the Tesla will only charge and discharge between 20 and 80% of capacity, depending on environment etc., charge and discharge is controlled depending on various parameters. Remember the Chevy Volt which caught fire about 2 weeks after a crash test.
A containment and updated procedures after accuidents have been the results.

My gut feel is that we will see something like this as a solution for the Dreamliner:
1) A specific fire and smoke monitoring system, as well as additional temp sensors (probably incl. a camera will be installed)
2) Software, and data cal regarding charging and discharging strategies will be updated in direction of 'more conservative)
3) A regular Battery exchange cycle will be established (like a bottle deposit and return system in Europe)

4) Boeing in the meantime will work on an update of the battery system with a different less risky battery system and get this extensively tested and certified (maybe in 2 years from now) and also will develop a PIP for existing planes for that.

This is what my crystal ball sees coming down the road (air).

Regards

Flyglobal

Quoting sweair (Reply 19): A fuel cell is a bit kinder to the environment than the APU as that is a small jet turbine itself. A fuel cell can use multiple fuels and create less pollution and noise. Maybe the cost and the heat is a problem?

1) They are still a new and unproven technology.

2) They run at 400-800°C, which brings up a whole array of thermal containment issues for certification.

3) They would have to crack the fuel for hydrogen and then combine it with oxygen, leaving us to do what with the carbon?

Quoting DocLightning (Reply 19):

I wont have to be hydrogen, it can be jet fuel or methanol or any other hydrocarbon source for a fuel cell. Airbus and Boeing are both researching fuel cells. One day we could do away with the apu and batteries. Its sadly no option on the 787.

But to be an optimist, maybe this incident will lead to greater efforts to make the fuel cell a viable option for commercial aviation in the future.

Well, the PAF technology to generate Hydrogen gas from Kerosenes are at an experimental stage and then we are talking about output of only 5kW.



Plasma and hydrogen on a plane to me says: This is even more dangerous than Lithium-ion battery - dare I mention STS-51 Challenger.

Quoting LN-KGL (Reply 21): Plasma and hydrogen on a plane to me says: This is even more dangerous than Lithium-ion battery - dare I mention STS-51 Challenger.

I think fuel cells on planes are an inevitability. I just am very doubtful that it will be one of the earlier applications. I think we'll see vast batteries of fuel cells powering ships before one flies aboard an airliner.

The small consumer fuel cells are fueled with methanol, quite expensive but people like them as they work 24/7 compared to solar power on boats etc Almost no noise as well.

They do create waste heat though. Fuel cells for vehicles seem to be towards hydrogen.

Quoting sankaps (Reply 3): Well -- they are being proactive right now!

Like they did after two events that could have been catastrophic?? No, the FAA acts as they always have - reactive.

Quoting PC12Fan (Reply 24): Like they did after two events that could have been catastrophic?? No, the FAA acts as they always have - reactive.

Well, if that is your definition of reactive, then no new airplane or technology would ever fly. There is a "tipping point" at which one must act. Waiting too long would be reactive. Acting too early would just kill all innovation. Acting at the tipping point, before something calamitous happens, is prudent and proactive (in that they don't wait for an actual crash before they act).

Quting flyglobal: "And so will be other LI Car battery systems, like the Chevy Volt and newer Toyota's. Automotive use requires you to have your batteries at Winter in Canada and Russia (-40°C) and also at 100°C at least for heat (Death Valley, India, to name some location)."

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.....

Quoting Braybuddy (Reply 4): Quoting RottenRay (Reply 1): And, frankly, positing a battery meltdown followed by severe turbulence is something best left to Hollywood. Murphy's Law.

Fortunately for all of us, airplane's aren't designed to Murphy's Law...otherwise they'd never fly. Murphy's Law does get applied to individual components...you have to be handle an single failure, regardless of probability. But if you play that game with compound failure you can't ever certify. So they regulators establish acceptable risks of a catastrophic event due to multiple causes and you work backwards from there to what's acceptable probabilities for the contributing events. The probability of a battery meltdown combined with turbulence on the same flight is going to be very low...probably not 1 in a billion low, but that's OK because battery meltdown plus turbulence isn't enough to be catastrophic. You'd need at least two other failures (probably four).

Quoting AirlineCritic (Reply 7): A more significant modification, such as fluid venting out of the aircraft or even enlarging or moving the battery containment structure could take much longer. Half a year for venting out, years for moving the structure or making the EE bay larger to fit the new containment structure.

They're not going to make the EE bay larger, nor would they need to. There's enough room in there to put a solid steel box with 1" walls, no problem, which would be gross overkill on containment. I think people are also underestimating the speed with which the OEM's and regulators can move when something really is their top priority and they put "all" their resources on it. Boeing did a much more substantial redesign of the power system, including designing, building, and installing new hardware and software, after the ZA002 event and that only took about 6 months.

Quoting sweair (Reply 8): Just maybe we will have to accept that lion batteries will catch fire, on any airplane that uses them.

No maybe about it...even if you design a battery that will never catch fire, you'll still have to design it to survive in case it does.

Quoting art (Reply 12): Assuming (a) the cause of the overheating problem were identified (b) a fix had been designed, built and tested to a level where it would be acceptable to FAA (c) a fix for the containment issue had been designed, built and tested to a level where it would be acceptable to FAA, how long would it take the FAA to certify the aircraft as being safe again?

Days. Normally you develop the certification plan ahead of, or in parallel with, the design/build/testing. That way, as soon as you have the result, you sign the last line on the paperwork and you're done.

Quoting art (Reply 12): Once the aircraft were certified as safe, how long would it take to put the revised components into production and start installing them on the 787's delivered so far?

Weeks. You need to inject the change back into the production system at the point it makes sense (probably at the partners that stuff the sections containing the EE bays). You would rework all airplanes downstream of that in final assembly, or after assembly on the flightline.

Quoting sweair (Reply 16): A fuel cell is a bit kinder to the environment than the APU as that is a small jet turbine itself. A fuel cell can use multiple fuels and create less pollution and noise. Maybe the cost and the heat is a problem?

Multiple fuels aren't much use in this particular application, since you have an ample supply of a perfectly good fuel (Jet-A) and nobody wants to design/build/test another fuel system when you don't need one. Boeing has already tested fuel cell's for aviation use as part of the ecoDemonstrator program last year.

Quoting flyglobal (Reply 17): 1) A specific fire and smoke monitoring system, as well as additional temp sensors (probably incl. a camera will be installed)

I'll eat my hat if they put in a camera.

Quoting PC12Fan (Reply 23): Like they did after two events that could have been catastrophic??

I'm still waiting for somebody to explain a foreseeable chain of events that ends in catastrophe, given how the airplane is designed. FAA/NTSB must have one in mind, given their statement, but they're not sharing. Lots of people have opined that the plane was "lucky to not have crashed" or words to that effect, yet I haven't seen one example of a foreseeable catastrophic failure chain.

Also, replying to a comment in Part 5 that I didn't get to before it was locked regarding LRU succeptability to liquid contamination in the aft EE bay (the accusation was that I'd never held an LRU)...the design criteria for the aft EE bay are quite different due to the presence of the liquid cooling system and high power density back there...the LRU's don't look like normal federated LRU "black boxes". Even in the forward bay, the liquid tolerance of LRU's is quite a bit higher than most people would think...even in normal operation, you've got no way to make sure that someone doesn't spill a couple of gallons of liquid (likely cleaner) on the main deck that drools down into bilge and EE bays.

Tom.

Quoting tdscanuck (Reply 25): Boeing has already tested fuel cell's for aviation use as part of the ecoDemonstrator program last year.

I think Airbus has (or is in the process) as well - If my memory serves me well, it was to substitute the APU.

Quoting tdscanuck (Reply 25): The probability of a battery meltdown combined with turbulence on the same flight is going to be very low

Another comment which barely reflects facts or knowledge. The 787 is (or was) ETOPS certified and those Transatlantic tracks are not fixed. They change every day to avoid headwinds or make use of jet streams (west wind drift) and those turbulence associated to jet streams are hard to avoid on trans oceanic crossings. I hardly ever had a crossing where I didn't encounter turbulence. Even flight plan providers like Lufthansa's LIDO use live data to calculate routes with maximum tailwind (or minimum headwind) even if not straight - downside is that those are often along jet streams and turbulence.

Rgds, AlfaBlue

http://www.technologyreview.com/news...693/fuel-cells-take-to-the-runway/

http://oilprice.com/Latest-Energy-Ne...en-Fuel-Cell-Powered-Aircraft.html

You would still need batteries even with a fuel cell/fuel cells?

Quoting alfablue (Reply 27): Quoting tdscanuck (Reply 25): The probability of a battery meltdown combined with turbulence on the same flight is going to be very low Another comment which barely reflects facts or knowledge.

The comment I was replying to specifically referenced severe turbulence. I didn't repeat "severe" because I was typing quickly (shame on me) and was obviously replying to a direct quote:

Quoting Braybuddy (Reply 4): Quoting RottenRay (Reply 1): And, frankly, positing a battery meltdown followed by severe turbulence is something best left to Hollywood. Murphy's Law.

The context we're talking about is bouncing electrolyte around the EE bay. Since the battery is at the bottom, it's only possible to get the electrolyte to go up any significant distance in any quantity if you get up to near 1g turbulence, which is consistent with the technical definition of severe turbulence.

Quoting alfablue (Reply 27): The 787 is (or was) ETOPS certified and those Transatlantic tracks are not fixed. They change every day to avoid headwinds or make use of jet streams (west wind drift) and those turbulence associated to jet streams are hard to avoid on trans oceanic crossings. I hardly ever had a crossing where I didn't encounter turbulence.

Exactly. Airlines spend extraordinary efforts to avoid even moderate turbulence...the probability of encounting servere turbulence, by itself, is already small. Compounding that with a battery fire, which is also small (though not nearly as small at the moment as anyone would like) gets you to a *very* small number. Then pile on the fact that you actually need the "bounced" eletrolyte to actually fail multiple other components before you threaten the aircraft, you'd out into very very small probabilities. Maybe not 1 in a billion, which is what the FAA requires, but they've got to be close.

Tom.

Quoting RottenRay (Reply 1): Really and truly, these situations just don't line up like that. Outside of Hollywood, that is.

Actually it did happened two weeks ago when a commuter train crashed into a house.
Caused by a chain of events/factors so unlikely that they together actually made the impossible possible.

http://www.japantoday.com/category/n...l-unable-to-find-cause-of-787-fire
This is nuts. Wouldn't they be better off with a replacement source of electricity that can readily be approved until they figure this crap out, instead of just dragging this on?
Yesterday's JL 7 was op'd by a 77W. I'm sure it was quite the sight in BOS.

Has NH and JL been shouldered the burden of reimbursing stranded pax? Wouldn't the DOT make Boeing pay this?

Quoting tdscanuck (Reply 29): Exactly. Airlines spend extraordinary efforts to avoid even moderate turbulence...the probability of encounting servere turbulence, by itself, is already small. Compounding that with a battery fire, which is also small (though not nearly as small at the moment as anyone would like) gets you to a *very* small number. Then pile on the fact that you actually need the "bounced" eletrolyte to actually fail multiple other components before you threaten the aircraft, you'd out into very very small probabilities. Maybe not 1 in a billion, which is what the FAA requires, but they've got to be close.

May I inject a small dose of reality. The probability of a thermal runaway, coupled with severe turbulence that somehow throws a paste electrolyte into systems that are designed to withstand cooling system liquids, and that causes multiple other systems to fail, is somewhat less likely than the probability that the flight crew will suffer simultaneous heart attacks (or that consumer electronic devices on board an aircraft will smoulder/vent/explode in flames - the FAA has 132 documented incidents just within its jurisdiction).

The reality is that the predominant cause of accidents is pilot error. Aircraft systems are generally far more robust than (most of) the people who fly them. Most design recommendations from safety boards are directed towards mitigating pilot error.

And I should add, this is coming from someone who has flown military aircraft in anger.

Quoting PHX787 (Reply 31): Has NH and JL been shouldered the burden of reimbursing stranded pax? Wouldn't the DOT make Boeing pay this?

Which stranded pax? Anyone disrupted in the first couple of days were long ago reaccommodated, and those on flights continuing to be cancelled are being reticketed.

Quoting tdscanuck (Reply 29): The context we're talking about is bouncing electrolyte around the EE bay. Since the battery is at the bottom, it's only possible to get the electrolyte to go up any significant distance in any quantity if you get up to near 1g turbulence, which is consistent with the technical definition of severe turbulence.

Come on, you know better.
Every certification requirement, and that includes the special Li ion certification requirement, is issued for the whole certified flight envelope, including severe turbulence. If not, there would have to be operation limitation on the aircraft.

Quoting tdscanuck (Reply 25): Lots of people have opined that the plane was "lucky to not have crashed" or words to that effect, yet I haven't seen one example of a foreseeable catastrophic failure chain.

Hmm... I wonder if they have a concern about the external venting. Were that to become blocked early in a battery event, say by melted material, could it cause enough pressure buildup to burst the containment?

Quoting PHX787 (Reply 31): Has NH and JL been shouldered the burden of reimbursing stranded pax? Wouldn't the DOT make Boeing pay this?

I don't think the FAA or the DoT would have anything to do with it... it's a matter of the warranty terms between Boeing and the airlines.

Quoting PHX787 (Reply 31): Has NH and JL been shouldered the burden of reimbursing stranded pax?

Yes, for those that are stranded. Are there any left?

Quoting PHX787 (Reply 31): Wouldn't the DOT make Boeing pay this?

Generally not. Even if that were the policy (and it's not), DOT has zero jurisdiction on what happens with a Japanese carrier's reimbursement policy.

Quoting packsonflight (Reply 34): Every certification requirement, and that includes the special Li ion certification requirement, is issued for the whole certified flight envelope, including severe turbulence. If not, there would have to be operation limitation on the aircraft.

That's true for normal operation, not generally generally true of failures. There are quite a few failures (mostly in the flight controls) that will limit the operational envelope of the aircraft. The special conditions require that damage due to vented gas/fluid from a fried battery be a certainly likelyhood...if severe turbulence is required to get to that damage, the probability of severe turbulence would play into the probability calculation. It's somewhat similar to not having to assume that lightning strike probability is 1, even though you have to design for a lightning strike. Also, severe turbulence, by definition, implies brief periods of loss of control, which is *also* outside the operating envelope.

Tom.

Quoting pliersinsight (Reply 24): Quting flyglobal: "And so will be other LI Car battery systems, like the Chevy Volt and newer Toyota's. Automotive use requires you to have your batteries at Winter in Canada and Russia (-40°C) and also at 100°C at least for heat (Death Valley, India, to name some location)." 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.....

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

http://www.foxnews.com/science/2012/...orld-hottest-temperature-declared/

In India, some parts of the Thar desert might go up to 50-52C (122-126F) in peak summer, not more than that!

Cheers,
Vivek

Quoting AirlineCritic (Reply 7): ETOPS limitations,

Sadly, I think that is likely.   At least for a bit.

Quoting sweair (Reply 15): A fuel cell is a bit kinder to the environment than the APU as that is a small jet turbine itself. A fuel cell can use multiple fuels and create less pollution and noise. Maybe the cost and the heat is a problem?

Besides otherwise mentioned limitations, fuel cells are heavy for the power delivered, have a slow start time (APUs must *start* and immediately deliver the needed power), and as already noted are unproven. Aircraft are conservative.

Let's put it this way. Lithium batteries are standard in the world I live in. Other options haven't been discussed for years. Yet everyone is treating them as an unknown. (This is but a larger scale implementation that didn't go well.) While I think fuel cells are destined to go on aircraft eventually, that is a long ways away.

Lightsaber

Have been fascinated and (sometimes) enlightened by these threads. Just hoping that in this latest iteration we can at least avoid the "it's a political conspiracy!" posts.

Look, having worked in government both on the political side (on Capitol Hill), and on the civil service side (in NYC), and in between, working in a regulator-heavy position at an i-bank, let me tell you: IT DOESN'T WORK THAT WAY.

The FAA, and especially the NTSB, are going to be even more stocked with civil servants than political appointees than the average agency. These are people who are there year in, year out, regardless of who's elected to what. These are the sort of people who, if the political folks DID want to pursue some industry-crushing conspiracy would be running to Huffington Post or Drudge Report with incriminating evidence.

Bureaucracies are built to be cautious, and are just as subject to fears of how a failure will make them look as anyone else. They can make mistakes, and people at key decision points can make different calls than we might when juggling several competing factors. But let's cut all this nonsense about "Oh, Obama is mad at Boeing", or "The Europeans are behind it!" and all that other junk... The FAA made the call that grounding 50 very high-profile planes until there's a clear answer about a scary (if not necessarily life-threatening) recurring flaw with a new technology was going to be safer, and less damaging to the airline industry, than letting them keep flying and just seeing what happened. Even if you, personally, wouldn't have made that call with the information we have available, you can't say there's not a solid case to be made for it.... rather than some malicious conspiracy!

Quoting nycdave (Reply 39): The FAA made the call that grounding 50 very high-profile planes until there's a clear answer about a scary (if not necessarily life-threatening) recurring flaw with a new technology was going to be safer, and less damaging to the airline industry, than letting them keep flying and just seeing what happened. Even if you, personally, wouldn't have made that call with the information we have available, you can't say there's not a solid case to be made for it.... rather than some malicious conspiracy!

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   

Quoting cornutt (Reply 35): Hmm... I wonder if they have a concern about the external venting. Were that to become blocked early in a battery event, say by melted material, could it cause enough pressure buildup to burst the containment?

That's certainly a good option...it would be consistent with all the FAA/NTSB comments I can think of so far and explain their concerns. Without seeing the spec document, we don't know what the requirements were for the battery vents but, if the battery vented but not the way it was supposed to, that would probably screw up all the other potential systems effect analysis for things in the vicinity of the battery.

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

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. Unless there's a whole lot of hidden information that's being suppressed but with multiple investigating bodies and agencies that's basically impossible. If it does turn out to have been obviously over-conservative I feel bad for anybody at the FAA who gets yelled at...they had to make a call with very little data to work with. Somebody has to make a call, one way or the other, and they won't always be right.

Tom.

Quoting tdscanuck (Reply 36): The special conditions require that damage due to vented gas/fluid from a fried battery be a certainly likelyhood...if

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. Apparently FAA is not happy with the containment on those two occasions.

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

I think they are simply doing their job. Without a credible explanation of why those two batteries went up in flames you really can not say they are not acting in good faith.

I tried reading through the entire topic from 1-6 and did not see this questions posted.

Does the 748 series use the same type of battery or batteries that the 787 is having issues with?

Quoting vivekman2006 (Reply 37): OMG No! Nowhere on this planet does the air temperature reach 100C (212F) Not even close!

Not in nature but in a Sauna you can go up to 120 deg C. Humidity is zero, though.

Quoting vivekman2006 (Reply 37): 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

. . . and I've been in 135F in Palm Springs

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

You quote a post that you have not understood at all, apparently.

Quoting cornutt (Reply 35): Hmm... I wonder if they have a concern about the external venting. Were that to become blocked early in a battery event, say by melted material, could it cause enough pressure buildup to burst the containment?

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.

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.

Interesting point. How much smoke would be generated, and how toxic would it be? 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.

Quoting packsonflight (Reply 42): Apparently FAA is not happy with the containment on those two occasions.

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.

History is rife with aircraft which were globally certified and later found to have flaws which required redesign. In these cases, no person or aircraft was lost, damage was limited, the flawed parts were identified, removed and are being thoroughly tested.

The causes will be discovered and solutions offered. Perhaps an interim solution will be presented to get the fleet flying again, until a permanent modification is certified.

Quoting PC12Fan (Reply 22): Like they did after two events that could have been catastrophic?? No, the FAA acts as they always have - reactive.

Why would the FAA act on a system they certified when there was no fault? They aren't psychic...they can't know ahead of time of every possible failure and pre-emptively ground aircraft, ala Minority Report.

They are proactive in their certification processes. They take specific data about a particular plane, study how similar systems have failed in the past, apply past and present knowledge to potential future problems and eventually certify an aircraft.

Of course they are reactive after an accident...they can't react until they have something to react to, and since it is impossible to think of every possible failure scenario, sometimes lessons aren't learned until people die. In these cases, the certified containment worked well enough that all people and the planes survived.

When the 787 is re-certified, it will be an improved plane...but it is probable that there are potential problems yet to be discovered...and will have to be fixed in the future. I doubt there is an aircraft flying without a host of AD's on it...and every one a mandatory fix or modification.

Quoting sweair (Reply 28): You would still need batteries even with a fuel cell/fuel cells?

If you had H2/O2 powered fuel cells, you'd need enough power to open the valves to the tanks, assuming the tanks were pressurized. You'd also need some regulation, but that can be done mostly mechanically.

You'd also be looking a reasonable lag before these came up to full power, which they won't do until the catalyst gets warm enough.

If you're running Jet-A and air into your fuel cell, you'll need to heat up the reformulator first, so you can decomposed the Jet-A, which will take both time and a fair bit of power.

A battery will supply power *right now*.

A fuel cell might be a reasonable alternative to an APU, but *not* the batteries.


ed:

Also, fuel cells don't produce all that much power (watts) for a given weight of fuel cell. They are useful because they can convert fuel into (electrical) energy (watt-seconds or Joules) with considerable efficiency, so the total mass of your fuel+fuel-cell system can be much, much lower than trying to same number of Joules out of a battery. But it will delivery those Joules much more slowly than a battery (IOW, fewer watts).

Batteries are much better for high, but relatively short, loads.

[Edited 2013-01-28 00:39:03]

Quoting pliersinsight (Reply 24): Quting flyglobal: "And so will be other LI Car battery systems, like the Chevy Volt and newer Toyota's. Automotive use requires you to have your batteries at Winter in Canada and Russia (-40°C) and also at 100°C at least for heat (Death Valley, India, to name some location)." 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.....

Automotive specification for max temperature for components:

Cabin mounted components: max operating temp 85 deg C
Components mounted in engine bay: max operating temp 105 deg C
Components mounted on the engine: max operating temp 125 deg C

For most parts the minimum operating temperature is -40 deg C, but most cars are calibrated only for guaranteed starting at -30 deg C.

So lead acid batteries are mounted in the engine compartment and are rated to 105 deg C temp only (internally they can get a bit warmer) while Li-Ion batteries for hybrid and electrical cars are placed in separate compartments under the floor of the car and as such are only rated up to 85 deg C.

And talking about fuel cells - they are even further away. Fuel cells have not improved significantly over the last 20 years. I always hear it is the next big thing. But I can research in them seeing cut back. For example, a fuel cell car trial in Singapore was stopped with the hydrogen refilling stations being dismantled and replaced by a trial of electric cars. Same for RR stationary fuel cells (about 400kW) research - it was always promoted by the local researchers but now seems to have gone quiet while at least 3 labs (bunkers) for Li-Ion battery research have been built or are being built.
BTW an exploding Li-Ion battery at solar research lab of NUS was responsible for the quite spectacular flames last year:
http://www.channelnewsasia.com/photo...gallery/gallery_20120810181310.htm
(the fire looked a lot worse than it was - the only thing which cought fire was the ventilation duct from the lab to the roof).