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Boeing's Dreamliner turns into a nightmare due to bad analytics

The problems with this plane, which forced FAA to ground all of them today in US, is its new type of lithium-ion battery made in Japan, and never used in a plane before. This type of powerful battery is overheating easily, catches fire etc. resulting in a number of emergency landings over a short period of time.

Now I have a few questions:

  • Aren't these batteries (like pretty much any product that you can purchase, such as car or laptop battery) going through extensive quality control testing, using sound statistical techniques to make sure that faulty batteries, or risk of failure over the lifetime of the product, is below an acceptable threshold, say below 0.001%?
  • Could it be that the quality control tests were not performed according to best practices? Maybe overheating simulations were not representative of real word conditions as found in an airplane taking off, or did not "stress" the battery for long enough? From a statistical point of view, this would amount to poor design of experiment. Something the FAA should carefully look at before allowing the Dreamliner to fly again.
  • Maybe standards for quality control are lower in Japan? Or greed played a role? Maybe statistical reports about the reliability of these lithium-ion batteries made by this Japanese company were fraudulent or wrong?
  • Maybe Boeing could have used better mechanisms to cool this type of battery, which has never been used in an airplane before, but found in all cell phones, and responsible for spectacular cell phone fires in the past. Unlike in a cell phone or a laptop, it is very easy to cool (and freeze) anything in a plane since the outside temperature is well below freezing point. Could this be used to fix the problem?

What are your thoughts?

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This seems to contradict what the AP posted today (1/22):

"The burned insides of the ANA battery showed it received voltage in excess of its design limits.

However, a battery that caught fire in a Japan Airlines Boeing 787 in Boston earlier this month was found not to have been overcharged. U.S. government investigators said there could still be problems with wiring or other charging components."

 

My GUESS would be that the first case was caused by an error in the power management software.  The second case still could be anything.

Let us first look at the safety record of the aerospace industry and the complexity of a modern aircraft!  Considering the number of flight hours, takeoffs and landings, and conditions in which they perform, it is utterly amazing that there are not more problems.  Considering just the software in a modern aircraft --  how often do we deploy systems with 10s of millions of SLOC without having significant issues -- the readers of this article should review some of the standards that critical aerospace software must meet (for instance DO-178 B  -- in particular Level A software) to understand the effort that goes into making aircraft as brilliantly safe as they currently are!

I totally agree that the aerospace industry has a very good record.  It is truly amazing how safe these machines are, given how immensely complex they are.  Frankly, they have to be safe, else no one would fly.

I've read somewhere that the batteries were tested for 1,500,000 hours according to Boeing. But if the batteries tested all come from a same faulty batch, or few landinggs / take-off were involved, it defeats the purpose of statistical quality control testing, and it's almost as if they weren't tested at all. I'd like to read opinions from experts on this matter.

Having spent years in military/aerospace-grade electrical component manufacturing, I'm tempted to view these failures as a flashback to the Morton-Thiokol o-ring space shuttle disaster. Certainly the engineers had some inkling that there was a risk here, and it's possible that the cost to address the issues was prohibitive both financially and timewise for an already delayed program.

The analytics behind these tests are described in the "Handbook of Engineering Statistics" published by Springer in 2006.

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