A steel box is all well and good but surely a safety cased based on containing an energetic fire is only acceptable against risk up to some probability of occurance. If you don't know what the probability of occurrence is, how do you make the case?

As I recall, there was at least 1 engineer (who was sacked by Boeing) for telling them they needed more testing of this aircraft, especially the battery and electrical systems, before it should be put into commercial use.

In usual fashion the beancounters won out, the aircraft was pushed out the door so Boeing could book some revenue, and now the mess needs to be mopped up, and will end up costing far more to put right, than it would have if done properly in the first place.

No, there is no risk here so it is pointless to talk about "probability". There is only probability of inconvenience to the airline if the battery goes bust in mid flight - at destination aircraft will have to be serviced, most likely the next flight will be cancelled. As to probability - it can be approximated - there was another occurrence after the "fix" so the battery fails about once per ... say 10,000 flights but then other components also do fail and more often than that. And by the way, there is no "energetic fire", there is hardly any fire since the steel box also cuts the battery from oxygen supply. And this is exactly what happened when it failed last time - the battery with the steel box were swapped.

Who gives a **** about 1 engineer, there could be even 100 engineers, the extent of testing is strictly determined and controlled by the certification agency.

Nice attitude. The report states that the certification process was flawed. This Engineer knew it, WAS ULTIMATELY PROVED CORRECT, but was a hinderance and so he was sacked. Gives him a pretty strong case I'd have thought.

As for the oxygen thing, I thought the cells generated their own during runaway so it's a mute point - still the battery is self destructing inside a nice box so it's ok.....:hmm:

No, cells don't generate own oxygen.
Also it is the FAA that decides what certification process is, not the NTSB.

"Also it is the FAA that decides what certification process is, not the NTSB"

Many years ago the Sunday Times Insight team wrote abook about the problems with the DC10, ultimately leading to the Paris crash (Destination Disaster). In it, the FAA is described as "fat, dumb and happy". It would seem that not a lot has changed.

You obviously have not spent any time actually dealing with the FAA :*

I concur with tdracer - never mind what the Sunday Times may, or may not, have said 'many years ago' - try listening to those of us who deal with them today, none of those adjectives would apply to those FAA folk I dealt with during my years in the Everett area either!

fenland I agree with you My dealings with the FAA have ALWAYS been conducted with extreme professionalism can't say a bad word about them TBH same with the CAA and EASA.

Well, the Japan Transport Safety Board has come out with their draft report that suggests extreme cold as a contributing factor to battery deterioration.

Battery problems plaguing Boeing's B787 Dreamliner may be tied to extreme cold - AJW by The Asahi Shimbun

I don't think the forward and aft equipment bays get that cold. Its pressurized and conditioned air in there. Probably close to the temps one would expect in the cargo spaces.

NHK had a comment on this yesterday. They said that it gets even colder in Europe, but similar problems had not arisen there, so the Japan Transport Safety Board is still not 100% sure they will finalize the report like this.

Reports elsewhere say that charging lithium cells when they are too cold causes lithium plating which can cause short circuits and failure. Cold for a consumer grade lithium is 0-5C. No idea what aircraft grade batteries consider cold to be.

I'm sure the tech is different but I think Tesla cars do different things when the battery is cold. I believe they have a battery heater to keep it within range and I think you loose regenerative braking until the battery is warm enough.

Edit:

http://batteryuniversity.com/learn/a...the_boeing_787

Have we heard from Canada? WardAir once told me Edmonton was a cold-soak heavyweight.

I concur. In my experience they do seem to be overworked, particularly in the manufacturing oversight area. I suppose Boeing, in conjunction with Congress, works to keep their funding down to levels where they are forced to rely heavily on the self certification process.

Are the lack of current B787 reports on Rumours and News section of pprune to indicate that the manufacturer and industry have now got to grips with the initial teething problems?

Al Jazeera TV has been advertising Broken Dreams, an upcoming documentary on the ups and downs of the Dreamliner. Very brave.

I suspect that some in the US will not be happy with such exposure.

I highly doubt anybody in the industry cares about what Al Jazeera has to say - on whatever subject.

olasek

Given the sizes of some Middle Eastern fleets, I suspect that Boeing will care.

If operators start basing their purchase decisions on TV Network hit pieces put together by people who barely know the difference between an airplane and a hair dryer, then the whole industry had better care.
BTW, the part about TV networks isn't particularly aimed at Al Jazeera - few of the other networks are any better.