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Electronics & Test

Did Boeing Battery Work as Designed?

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wbswenberg
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No Power Condition
wbswenberg   2/16/2014 11:31:53 PM
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Bob From Maine no if there is an all engine out then the RAT deploys.

etmax
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Re: Good, but is it good enough?
etmax   2/1/2014 4:42:15 AM
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Hi Thinking_J, I always follow and consider others observations of what I'm doing/saying as well as what others are saying. There's very few definitive truths in this world ecept that there aren't many and most ideas have a condition when they aren't a good idea, hence the untold value of listening to others.

a.saji
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Re: Good, but is it good enough?
a.saji   1/31/2014 9:19:49 PM
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There may have been certain downfalls but with time things do get better. Anyway battery lifespan gets decided mostly on the usage. Also when you are not using the battery and going ahead with power but constantly charging it too means you are draining the lifetime of the battery. 

Thinking_J
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Platinum
Re: Good, but is it good enough?
Thinking_J   1/31/2014 8:41:49 PM
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etmax: Thanks for considering my observations.... (as crazy as they are)

I do wish we could all get real, viable, timely data on all the battery types. You are correct , the referenced material left much to be desired.

I think I understood where you were coming from (the distinction between fire vs just "dying"). But in a aircraft, as long as the fire is contained - what does it matter? Both can kill you. As I pointed out in my earlier comments (rantings), a dead battery (critical sub-system) is handled with redunancy in most aircraft designs. Again, yes, Boeing SHOULD have contained this failure mode much better in the first place. They screwed up. I don't believe a different battery at this point would improve safety. It appears they finally have a containment solution in place.

a bit off subject....

As to most large large corporations regulating activity based on stock prices...

I know it seems this way to the casual observer. And there are most certainly examples of this out there. However, since GE's Jack Welch published his thoughts on the subject (early 1990s), most large companies DO NOT regulate any business practices based on stock valuations. The reasons are many. But the biggest reason applicable to this case: Stocks rise and fall faster than any engineering group can respond. And with FAA reviewing and approving every step an avionics engineer takes - the speed of change in the aircraft business is doubly slow. Sometimes the change happens "faster" but it really doesn't happen fast. (in this case, that is likely a "good thing"....hate to have solutions put in place that are not completely thought out).

One of the most dramatic changes Jack put in place at GE: No business practices are to be based on tax advantages. Basically, trying to avoid taxes caused many large companies into crazy business decisions that ultimately lead to their downfall. Thus the need to decouple what ever the Gov or Wall Street was doing from normal business operations. I wish more companys bought into that rule.

Don't get me wrong, I am not fond of Jack, but he was right about a few things.

etmax
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Gold
Re: Good, but is it good enough?
etmax   1/29/2014 5:20:54 AM
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@Thinking_J Good Handle :-)

I've read your rebuttal, and you do have some points. Allow me to elaborate:

First:"78 million miles --- compared to other technologies with no failures".

Well no fire & flames lets say. That is really what I meant

Sorry but the issue is "batteries with manufacturing flaws" or "batteries with flawed charging systems".. with very little relationship to time in service or miles flown).

This is a good point, although both will be brought to light by miles/hours in service me thinks.

The batteries in question: their track record is 1 flaw in 10 million cells produced. https://cen.acs.org/articles/91/i6/Assessing-Safety-Lithium-Ion-Batteries.html

Sadly that article seems to suggest that 1 in 10 million to be over all types of battery types from coin cell to car battery. An aircraft at altitude will see the operating environment from hell I imagine, as one article suggested air cooling is more difficult in low pressure environments. (yeah I know stats again)

I don't think Lead acid batteries have a track record that good (taking my cue from your musings and how often my car battery dies

Mostly car batteries don't catch fire was really my point, I agree they aren't that reliable although with correct procedures a failure can usually be predicted.


(I can poke fun at myself too! )

Very important, :-)

Everyone thinks they understand statistics.

How does it go? lies, damned lies and then there's statistics :-)

Why would anyone assume the airline industry doesn't already have similar or worse failure rates in other battery systems?

I think the biggest issue was the spectacular fashion of the fire and smoke. If a lead Calcium battery was used it would have had an internal cell disconnect or some chemistry poisoning to go Hi-Z, comparitively less worrisome.


Second: "not ready for prime time"...if industry nevers try anything new, what will happen to innovation or progress? Without some risk, all progress would stop. If we didn't'work through our failures, well, we would really be in a sad state. Is it being suggested that Boeing go back to a inferior technology that just doesn't get press coverage of it's failures?

I certainly wouldn't suggest this, I'm only saying that a battery who's failure mode is fire needs to be well thought out before it goes in a plane. (yeah I know they did think about it, just maybe not ask the right questions) I mean ceramic capacitors are not allowed to be wired in an appliance from line to earth becuase their failure mode is short which can make the chassis live but only if the earth is disconnected. Y rated capacitors must be used instead (usually metal paper or special metal polyesters). so here is an example of safety where the backup has to have a backup.

but I am sure if Boeing made it's design decisions based on stock market fluxuations

Actually I don't know any large company that doesn't regulate activity based on share price.

Maybe you're right and the battery technology isn't the issue, but regardless of that i don't think the auxiliary generator for a fly by wire plane should literally go up in smoke. One article mentioned that this battery in the new Boeing was replacing the traditional APU which has an exceptional record of safety (for weight and cost savings) which would mean that if all 4 engines stalled and the battery had to really deliver running the avionics and an eventual restart I'm not sure, it sounds like a real risk.

Sure APU's fail too, although less spectacularly.

Thinking_J
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Platinum
Re: Good, but is it good enough?
Thinking_J   1/29/2014 1:45:29 AM
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etmax: I have a few problems with the observations you presented...

First:"78 million miles --- compared to other technologies with no failures"... really? I have worked in this field. I am not aware of ANY technology on a aircraft that has NO failures. This is a bad game of misunderstanding the limited data presented - and jumping to conclusions. (Miles per failure? on a battery? in a aircraft? Sorry but the issue is "batteries with manufacturing flaws" or "batteries with flawed charging systems".. with very little relationship to time in service or miles flown).

The batteries in question: their track record is 1 flaw in 10 million cells produced. https://cen.acs.org/articles/91/i6/Assessing-Safety-Lithium-Ion-Batteries.html

I don't think Lead acid batteries have a track record that good (taking my cue from your musings and how often my car battery dies (most of the time: without catching fire) - I couldn't find a manufacturer that would publish their flaw rates)

The other battery offerings? I don't think they will fair any better... but I did qualify that with "I don't think" (I can poke fun at myself too! )

Everyone thinks they understand statistics. Most teachers of the subject don't really understand it correctly according to recent article by a leading authority on the subject. This authority is proposing we stop teaching the subject except to top math PHD candiates! Reason: Because of how it distorts society's expectations (and the impact this has on everything in our lifes, creating flawed understandings).

Why would anyone assume the airline industry doesn't already have similar or worse failure rates in other battery systems? Or these other battery failures don't require containment in a aircraft? Because it wasn't covered in the media it must not be happening?  A battery dying mid-air (even without fire) can be life threating also. Thinking of my new car's battery and it's very short life (2K miles - sigh). http://www.casa.gov.au/wcmswr/_assets/main/airworth/awb/24/008.pdf

Second: "not ready for prime time"...if industry nevers try anything new, what will happen to innovation or progress? Without some risk, all progress would stop. If we didn't'work through our failures, well, we would really be in a sad state. Is it being suggested that Boeing go back to a inferior technology that just doesn't get press coverage of it's failures?

Should we.... "design: based on media coverage"?

Third: (directed toward other's comments) Why would engineers be concerned with Boeing's stock prices? Yes, there is an impact due to battery failures in the financial world of Boeing, but I am sure if Boeing made it's design decisions based on stock market fluxuations it would never have become the company it is today. Read the story on each of it's landmark aircraft designs (not all their designs qualify as "landmark")... all are stories of extreme risk taking. Without this risk taking, there would not be an airline industry.

etmax
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Gold
Re: Good, but is it good enough?
etmax   1/24/2014 6:41:13 AM
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I think the real measure of this 78million miles is how many miles have been flown with other technologies that have had no failures, and I would believe it to be substantially more suggesting this technology is not ready for prime time. Why can't they just admit they've made a mistake, and switch to something that won't put people's lives at risk. What are they going to say when a plane comes down because of this? Their anti-fire mechanism has worked as designed, their battery has not unless it's designed to catch fire.

Charles Murray
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Re: Good, but is it good enough?
Charles Murray   1/22/2014 8:52:42 PM
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I agree, naperlou. Whether there is a fire or not, the lithium-ion battery pack is starting to become a sore spot for Boeing. As I understand, Boeing's stock was not directly affected by this latest adventure, but if they have more problems, it's going to continue to affect the reputation of a company that has done great things in the past.

Thinking_J
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Platinum
Perspectives (different) and assumptions...
Thinking_J   1/21/2014 6:48:52 PM
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I see people wanting the solution to be directed at the root cause.

Fine. And generally the best place to start for most products.

With this product (composite comercial aircraft) the game changes. Even if the root cause is known, the solution doesn't really change.

EVERY type of battery (energy storage) has some risk. It can NEVER be reduced to zero. There is no production process for batteries of any type that is 100% free of defects. Especially, with the energy levels required for this application.

Yes, it may not have been a significant issue protecting the aircraft from a lead acid battery doing "bad things" in a aluminum structure. But it would not be as simple in this aircraft. Much more complex than just being bigger and heavier. Lead acid batteries do explode due to manufacturing defects (not just over charging, shorting, etc.)  - in the field.

The issue is still remains (what you do to protect the aircraft when this energy storage device goes "bad"). The basic reason why there are so many redunant systems on a commerical aircraft - there is no way to guarantee 100% (safe) operation of any of these critical sub-systems.

And traditionally the avaition industry addresses this with containment and redunancy.
Why it wasn't properly addressed during the first release of this aircraft is a bit of a mystery to me. But now, this issue appears to be addressed.

 

William K.
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Re: Meeting User Needs
William K.   1/21/2014 4:08:35 PM
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@Jhank. I am certain that the engineers at Boeing went through the design verification and validation most carefully. They may even have done that twice. I am certain that the specific conditions that have caused the failures that have been seen were never part of that study, or, more likely, the numbers used in the original evaluation were not the same. To quote the late Bob Pease, "an incorrect model leads to an incorrect conclusion", meaning that if you are not able to include all of the correct data that the results will not be quite correct. And just like I posted already, it still looks like nobody who is talking understands the exact sequence of things that  has lead to these failures. And because there have not been many, and they are far apart, and didn't happen for a lot of hours, it would be quite a task to discern the cause.

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