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Dreamliner: Boeing 787 Aircraft Battery "Not Faulty"
SternisheFan writes "Airline safety inspectors have found no faults with the battery used on Boeing's 787 Dreamliner, Japan's transport ministry has said. The battery was initially considered the likely source of problems on 787s owned by two Japanese airlines. The world's entire fleet of 50 787s has been grounded while inspections are carried out. Attention has now shifted to the electrical system that monitors battery voltage, charging and temperature. Transport ministry official Shigeru Takano said 'we have found no major quality or technical problem' with the lithium-ion batteries. Shares in GS Yuasa, which makes the batteries, jumped 5% on the news. 'We are looking into affiliated parts makers,' he said. 'We are looking into possibilities.'"
Japanese government agency defending a Japanese company. I wait for a more objective report which I believe is in the pipeline.
The 787 is a revolutionary aircraft on many levels, from features to construction technology to production methods. I would expect there to be unforseen issues resulting from interaction between different systems. What I'm curious about is whether Boeing will get them all sorted out quickly enough...in which case they will be superbly positioned to compete, having mastered the many challenges around making the 787 what it is. If they don't, then they will be in terrible trouble. I feel like I'm watching aeronautical history playing out before my eyes.
I hope they get it all fixed in time, personally. The 787 is a hell of a plane. Check it out here: http://www.newairplane.com/787/
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Even though every pound saved cuts thousands of pounds of fuel and carbon emissions over the plane's lifetime, this extra is small compared to the total plane mass, passengers and luggage. Not to mention having and expensive plane out of service for possibly months.
Not entirely surprising, its usually the charger and/or the discharge protection ckts. Ask the RC electric airplane people who have at least a decade or so experience with lithium batteries in airplanes and burning them up. I was into RC planes back when everyone used NiCad but I've kept up with recent events. The batteries themselves rarely burst into flame, they burst into flame when you connect them to something that does something very naughty well outside the limits of the datasheet.
I think this will probably, in the long run, turn into a "EE ethics and morals class" debate. So discharging 15 amps out of a 10 amp pack results in a 0.001% chance (actually pretty high) of blowing the pack up per the data sheet. However not supplying 15 amps to the engine control system during an alternator malfunction (or whatever) means the engine shuts down and 500 people have a near 100% chance of death. "just follow that datasheet" stuff could kill lots of people, then again "ignore the datasheet" could kill lots of people too. So if you must use lithium batteries (why?), then you can find a local minimum death rate which will not be zero... of course finding that might have to be done via experiment on unwilling crash victims, whole nother ethical issue. Basically, we're trading human life for slightly improved gas mileage, which certainly makes me want to fly on a carrier using airbus products instead of boeing products, which has other ethical issues, etc. Is the ethical/moral failure the managers for doing it despite advice against, the engineers fault for not committing career and economic suicide by refusing to design a lithium aircraft pack, the supplier for making batteries for an unsuitable purpose, the arabs fault for making jet fuel so expensive so we have to kill people with lightweight batteries, ...
The simplest thing is a battery drop tank arrangement or a rather stout thick wall steel case, making the works heavier than using old fashioned lead acid.
"Science flies us to the moon. Religion flies us into buildings." - Victor Stenger
Actually it would not help. The nasty thing about these battery fires is the battery chemistry SUPPLIES OXYGEN.
The battery charging voltages and currents are logged, the logs go to the flight recorder, and they don't indicate overcharging. There are monitoring circuit boards in the battery case, separate from the charger, which report this data. Either the charger failed in some way that caused an overcharge without the voltage sensing detecting this, or the battery itself failed.
The NTSB says they haven't found anything defective yet. The burned battery is enough of a mess that it's hard to extract much info, but they're using spectroscopy to check that the composition of the components was correct.
The grounding is necessary. The JAL aircraft at Logan only had 22 takeoff/landing cycles on it, and this has now happened twice, so the odds of further trouble are high. Over the next few days and weeks, batteries and chargers will probably be pulled from other aircraft and cycled through pressure chambers, shake tables, and hot/cold cycles in attempts to induce the failure.
Meanwhile, I suspect that there are frantic efforts at Boeing to design a replacement that doesn't use lithium-ion batteries.
I once tried to put out a burning SOLAS flare and no amount of throwing crap on it would work. It was kind of embarrassing so I threw it over the side and then the fkn thing is burning UNDERWATER and producing all kinds of smoke and steam PLUS lighting the water up bright red. No.....nothing going on here......oops...
So what you're really saying is "Take the number of [batteries] in the field, A, multiply by the probable rate of failure, B, multiply by the average out-of-court settlement, C. A times B times C equals X. If X is less than the cost of a recall, we don't do one. "
The actual answer is more nuanced.
FAA regulations define 5 levels of critical for safety systems: levels A through E.
Level A is for things that can knock a plane out of the sky when they fail; for example the stall speed alarm.
Level C is for things that can cause injury or at most a single death; for example, the cabin pressurization system
Level E is for things that don't affect flight safety; such as, in-flight entertainment or the microwave in the galley
For reference, I wrote the software for cabin pressurization systems. It's level C (hardware == B), which means that failure in pressurization is an emergency situation, but isn't expected to kill everyone on board. The masks drop and the pilot immediately dives to under 10,000 feet to restore breathable air.
If the cabin fills with smoke, it's not life-threatening per se. The pilot can override the pressurization system and "dump" the cabin atmosphere, and it clears pretty quick. (The captain also dives to under 10,000 feet if necessary.)
The battery catching fire isn't a problem SO LONG AS the fire itself won't cripple the aircraft. The battery underpowering the plane when the alternator dies MAY BE a problem which would kill people.
The people who design these things take these levels into consideration, and the general rule is "fail safe". If you can't "fail safe", then "fail in the least dangerous way". In my experience, the engineer must make many choices when designing an aircraft unit. The answer is always "do it *this* way, because if *that* happens it will be less dangerous.
Let's wait and see what the investigation uncovers. Here are some Cliff notes:
1) Li-Ion batteries might behave differently at altitude (cabin pressure is reduced while flying)
2) The battery may be performing to spec, while trying to compensate for a more dangerous problem
3) Smoke in the cabin is not as dangerous as you might think
4) Things that burn are designed to not damage things when burning
5) People who design aircraft are pretty smart, and have a generally high moral standard.
6) People who investigate aircraft incidents are really, really thorough, and have a good track record.
(Note: Glossing over some details to make an easier read.)