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back to article Safety authorities to hold hearings into Boeing 787's battery woes

There's no end in sight for Boeing's woes with its combustible 787 Dreamliner: the National Transportation Safety Board (NTSB) has released its interim report about a fire on one of the aircraft, and announced that a full investigation into the 787's batteries will begin next month. "The information developed through the …

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Shurely

One of those boondoogle military subsidy planes boeing uses to unfairly compete with airbus has a suitable battery developed at huge expense that can be used. What the idiotz forgot to charge the pentagon for a beeeellion dollar battery for the 787. Boeing's dead if they can't remember how to cheat properly!

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Re: Shurely

Yeah, because Airbus receives no subsidies from Europe, or start up loans, or favourable treatment...

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FAIL

Re: Shurely

Can't have an article on any news site explicitly mention Boeing or Airbus without setting off a flag waving Eurofighter vs F22 like dick measure fest. The fact is they are both largely transnational corporations who source a whole lot crap from China just like every other corporation.

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Flame

NiMH

NiMH are heavier for same power, but similar power to volume and after 200 power cycles may actually beat lithium on capacity vs weight.

The extra weight isn't than much overall. Less likely to have thermal runaway.

Unsurprisingly Airbus who were considering Lithium Ion are going to stick with NiMH (though news item said NiCd, I suspect it's NiMH).

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Anonymous Coward

Re: NiMH

What about Lithium Polymer?

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Re: NiMH

LiPo batteries are still very much a fire risk, and require charging and use via a kid-gloves treatment.

That said, I notice that LiPo batteries do tend to be used in heavy-current-draw situations. They are usually rated between 15C and 30C discharge rate.

Wouldn't want to short one, though.

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Re: NiMH

LiFePO4 may be suitable though. No thermal runaway problems, much longer service life than LiPo, but a bit bigger and heavier for the same capacity.

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Re: NiMH

Or they could simply use Lithium Iron Phosphate. The Lithium Cobalt Manganese batteries they use are the same chemistry as those infamous exploding laptop batteries. LiFePO4 don't suffer from thermal runaway like the Lithium Cobalt do, and they don't generate their own oxygen either. Not sure why Boeing went with a much less safe battery chemistry, when the energy density difference between Lithium Cobalt and Lithium Iron is only a few percent.

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Lithium chemistry is problematical!

In San Jose (California) I knew a person who worked for a Lithium battery company. They had ALL sorts of problems with batteries "exploding". They were located next to the freeway, and she noted that regularly they would need to close it down to pick up the pieces.

I suppose they CAN be made safe, but some investigation on how they go into thermal runaway ought to be in order.

If you want explosions, go search for sodium in water. A small amount (1 kg) dropped into a lake will do the trick. There are videos of just this sort of thing. Fun to watch! I suspect that Lithium isn't much better, being more reactive and all that.

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Re: Lithium chemistry is problematical!

Wrong. Lithium is less reactive than sodium, closer to calcium in fact.

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Holmes

Re: Lithium chemistry is problematical!

Lithium may well be less reactive than sodium and thank goodness for that! However, when formulated into batteries it does have an 'interesting' recent history as El Register can show. It does appear that the electrical storage system has some issues yet to fully answer. 'system' in this case includes much more than the cells-battery-enclosure-shelf package, it should also and do doubt will include pre-commissioning handling, etc. and this makes the investigation much bigger if not harder work.

The lithium chemistry battery's ability to store large amounts of energy in a small and therefore light package does mean that should anything not work as planned there is considerable potential for harm. The issues appear to remain (a) what went wrong and (b) how to design it out of the overall system.

Speaking personally, I find it interesting, being part mystery (who or what dun it) and how to stop the nefarious (infamous) 'miss-happen' from gaining access to the system in future. Eventually we may all benefit from the greater understanding of 'storage systems' and this means the whole, end to end chain of input through charging and management to output train. What must concern those closely involved is the prospect of 'eventually'.

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Re: Lithium chemistry is problematical!

Sounds like they got a job lot of used Sony and Dell laptop batteries on the cheap.

At 25,000 feet above the Pacific this would have been a problem....

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A tenth of that?

"Boeing reported to the NTSB that the likelihood of its batteries failing was once every 10 million flight hours, but in this and a second case the batteries caused problems in less than a tenth of this time"

Er, yes. 1 million flight hours would still be 41,000 + days of flights, or 114 years. I think the Boeing has been 787 has been flying a little less than that!

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Re: A tenth of that?

Or 114 aircraft flying for one year

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Re: A tenth of that?

I'd imagine 107 hours is the figure for a battery 'failing' in the sense of failing to deliver any power. If 'failing' is used in the sense of bursting into flame and threatening the viability of the airframe, I would think 109 hours would be a more likely permissible MTBF.

There's an analogous situation with engines: in-flight shutdown* (increasing pilot workload but not directly threatening safety) may be permissible no more than every 107 hours, but uncontained failure (potentially throwing shrapnel into the cabin) is 109 hours.

* Separate, tighter rules apply to extended range twin-engine operations (ETOPS) for oceanic crossings in twin-jets.

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Yag
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Re: A tenth of that?

Beside, "Flight hours" doesn't mean much nowadays. Planes are used as much as possible (rotating the crew as needed) and often kept powered until the scheduled maintenance calls. Actually, it's not that a bad thing, as it means that critical problems may appears while safely landed instead of during flight.

For the record, I already had to investigate a bug that appeared only after a display unit was on for a whole *week*. Yes, it was reported by an airline, and yes it was a coding error from someone who thought "hey, she will only fly for a few hours however, so why bother".

And yes, it was a pain to reproduce...

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Unhappy

Re: A tenth of that?

it was a coding error from someone who thought "hey, she will only fly for a few hours however, so why bother".

Someone thought that way in safety-critical code? Please reassure me it was just the in-flight entertainment system.

Where's the scream icon?

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Facepalm

Re: A tenth of that?

Not really as this would be 114 batteries, so 114 x the MTBF.

If you car is build to last 5 years, it shouldn't explode after 1 minute on the base that there are 5 millions cars on the road.

The fact that 2 or 3 batteries failed after each others just makes it less of a statistical incident (or a one off).

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Re: A tenth of that?

>If you car is build to last 5 years, it shouldn't explode after 1 minute on the base that there are 5 millions cars on the road.

With five million you are probably assured of at least one car setting itself on fire at or on the way to the dealership. The odds are very remote for any one car but throw enough cars in the population and the odds obviously for a single incident greatly increase.

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Yag
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Re: A tenth of that?

"Someone thought that way in safety-critical code? Please reassure me it was just the in-flight entertainment system."

Erm... It was in DO-178B A-level software, so yes, it was safety-critical code.

The original bug report was about a non-disappearing warning (they usually have a 5 second timeout, but this one was stuck on the screen)

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"... and the auxiliary power unit (which keeps electrical systems going when the engines are switched off) began smoking."

"The cameras showed "a white glow about the size of a softball" coming from the APU..."

Wrong and wrong.

It was not the APU that was smoking, but the Li-Ion battery in the aft electrical equipment bay. The APU is situated as far back in the tail as possible.

I suggest a visit to :-

http://www.yomiuri.co.jp/dy/national/T130209002758.htm

to confirm locations of the errant pieces of kit.

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Technically, you are correct; it was the "APU battery", fitted quite a long way from the APU itself. However, this seems a bit tautologous, because any power unit without a source of power is just "a unit". For the purposes of most people, a "power unit" is the battery or brick with a cord.

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APU battery and the APU

The article fails as Magani says - but the comment added to iy by Intractable Potsherd only makes matters worse.

Essentially the APU is a gas turbine electricity generator. Once it is started it is the electrical power supply, and actually recharges the APU battery. If the APU fails, the APU battery should have enough power for required systems to fail safe, analogous to a computer UPS.

One of the APU Lithium batteries is the starter battery for an APU turbine engine located in the tail of the 787. Once the turbine (APU) is running it is generating AC to power all the systems that otherwise are powered by the main engines AC generators during flight. Part of the AC generated, either by main engines during flight or the APU when on the ground is converted to DC, which many of the systems run on. The power input or output of the APU battery is monitored, on the charging circuit, by the flight Data Recorder (FDR)

While it appears that one of the Lithium cells connected in series to form a 32v battery failed, the FDR records unexplained voltage fluctuation between 0-28v and current between 0 and 4-5 amps discharge.

It is not just a case of the the two Lithium batteries that caught fire, several charger circuit boards had failed, and had been replaced.

What occurred to me was that any anomalies in the charging circuits, or battery fluctuations, should be recorded in all the FDRs for all the 787s - all the ones that have flown and are now grounded. It is worth taking a look at all of them.

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Sacrifice some weight

As a workaround for the moment why do Boeing not use a NiMH (or even lead-acid) battery stack in the cargo bay cabled to the position occupied by the Lithium battery. It would increase the weight of the plane by a couple of hundred pounds and possibly reduce the number of cargo containers that could be carried by 1 but would allow the planes to continue flying while a permanent fix was being designed and implemented.

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Re: Sacrifice some weight

That sounds like a good working solution and you can do that to your personal Boeing 787, the one you don't fly in controlled airspace or use to carry passengers. Boeing have many constraints on what changes they are allowed to make and re-certification would take ages.

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Stop

Re: Sacrifice some weight

...possibly reduce the number of cargo containers that could be carried by 1

That alone would wipe out the cost savings from all the efficiencies carefully built into the rest of the aircraft. They could do that, but nobody would buy the things.

Remember, it's cargo where the money's made, not passengers.

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Re: Sacrifice some weight

The more this goes on, the more likely the Dreamliner is going to end up with the same fate as the DeHavilland Comet. Once trust is gone, it will not come back. Airbus 800 will become the airliner of choice, and Boeing will reprise DeHavilland's role as loser. Karma's a bitch ...

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Re: Sacrifice some weight

Out of interest - how much weight does the Lithium battery save, compared to an NiMH stack of the same capacity?

Would lead-acid be allowed in an aircraft? Spilled acid in an airframe would be very undesirable, even if gelled. Even more so, the hydrogen gas that the things emit under failure / overcharge conditions or when spilled acid finds something metal to react with.

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Re: Sacrifice some weight@frank ly

"Boeing have many constraints on what changes they are allowed to make and re-certification would take ages."

Well, the bureaucratic certification is self evidently bollocks, because the dodgy batteries were designed, fitted and released to service, and the failed quick release system shows that it wasn't just an unfortunate bit of chemistry that's at fault.

I accept that changes are complex, take time and need to be tested and properly documented. But FAA certification might as well have "now wash your hands" on the bottom of each piece of paper from a preventative point of view. Having said that if the FAA hadn't withdrawn the certification, I wonder if Boeing and the airlines would still be flying them (and hoping passengers would board them)?

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Headmaster

A couple of problems

Seattle Times said that Boeing outsourced most of the safety review to the battery company who not so surprisingly said "our batteries are FINE! No problem! They'll NEVER fail!"

Second, one of the airport firefighters got smacked in the neck by something when the battery exploded and burned a bit.

Third, they had to use the "jaws of life" style hydraulics to get the damn battery out.

http://seattletimes.com/html/businesstechnology/2020505762_ntsb787reportxml.html

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Re: A couple of problems

I noticed the difficulty the firefighters had removing the battery - "Firefighters reported that removing the battery was difficult because a metal kick shield installed in front of the battery prevented them from accessing the

battery’s quarter-turn quick disconnect knob. Also, the quick disconnect knob could not be turned because it was charred and melted."

Even if the knob hadn't melted, it was not "quick release" because some numpty had put put a sheet of metal in front of it! So, poor battery, and poor design of safety - what else is there waiting to be discovered?

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Trollface

A good old-fashioned two-stroke engine and generator to generate the neccessary juice?

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Using an engine to start the engine that starts the engines?

The phrase I'm looking for here starts with the words "Yo dawg..."

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So the point of the battery is to save fuel by not running the APU. So wouldn't the easy solution be pull the battery and run the APU? That way the planes can fly.

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Flame

I don't see what all the fuss is about!

This isn't a design problem, it's a marketing problem. And as we know from management, there's no such thing as problems, only opportunities.

So we know that passengers dislike horrible airline food. All that horrible microwaved goop. Solution:

Welcome to the new Boeing Dreamliner. Sit down, relax and enjoy our in-flight barbecue. You can have sausages, burgers, steaks, fish...

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Anonymous Coward

Thermal runaway and lithium-ion batteries ..

Aren't lithium-ion susceptible to localized heating leading to thermal runaway. As in filaments form on the plates that provide a localized path for excessive current flow.

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Anonymous Coward

For some light reading on the topic

http://www.pprune.org/rumours-news/505455-faa-grounds-787s.html

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"Deplaned"?

Please ban this word.

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FAIL

Don't cry for Boeing.

We have no need to pity Boeing over it's inability to keep it's 'plastic' plane in the air because the company has a large umbilical cord attached to the US Treasury as well having monopolistic manufacturing facilities for the Apache helicopters - the one the US Forces use for recreational killing of civilians and reporters in Iraq (see < http://www.youtube.com/watch?v=13qWADMfQnQ >).

I am sure the paid Boeing hacks are already soliciting Congress people, as well as the Pentagon, angling for a contract for the investigation in to the use by transportation community to (better) understand the risks and benefits associated with high capacity lithium batteries including military aircraft.

No doubt the delay is occasioned by the time taken to develop a snappy acronym for the project. Perhaps < www.acronymfinder.com > can give them some ideas.

The contract need not be large - say USD$5-billion - enough to buy off the airlines who have all these plastic things stranded at airports around the world.

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Re: Don't cry for Boeing.

Hey there.... perhaps anger management classes, or maybe just a liedown.

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