Boeing proposes full 787 battery fix to FAA: sources

Muddled wiring in American aeroplane

The US Federal Aviation Administration disclosed that it recently learned of new examples of faulty wiring on several Boeing aircraft

http://www.nytimes.com/1989/02/01/us/us-agency-broadening-inspections-of-boeing-jets.html

Following up on a fire in a Japan Airlines Boeing 787 Dreamliner Monday, United Airlines found improperly installed wiring on one of its 787s, The Wall Street Journal reported Tuesday.

Monday’s fire, at Boston Logan International Airport, has been linked to the battery of the auxiliary power unit, which provides power to start the engines and run systems when the engines are off.

An unidentified “person familiar with the inspections” told The Journal that United found an improperly installed bundle of wires connecting to the APU battery.

http://www.seattlepi.com/business/boeing/article/Faulty-wiring-reportedly-found-on-Boeing-787s-4175659.php#ixzz2LgV9ts8C

Made and Muddled in America

“(A) person familiar with the engineering work said the new box would be made of stainless steel nearly half an inch thick. It would be capable of containing an explosion, and would have a tube to vent smoke and flame outside the jet.

However, the source said engineers have raised questions about the safety of venting flames outside the plane, especially if it is on the ground and being fueled. The effect could be something like a flamethrower, this person said.”

Look at this vented container test of a much smaller li-ion battery:

http://www.rcgroups.com/forums/showthread.php?t=355739&highlight=test+ammunit+box

I don’t think it fair to compare an ammo box – which was never designed to contain an explosion – to the design being proposed by the Boeing engineers. That said, I am surprised at their statements about redesigning the batteries. Didn’t know they were in the battery design business. The rest of their proposal details a bandaid approach which doesn’t engender a lot of confidence.

Has anyone explained why they can’t return to the same kind of batteries used in previous planes until the real problem(s) with lithium ion batteries is solved by the battery manufacturer?

Boeing’s answer to the 787 battery issue is to try to protect the aircraft from a system which they acknowledge can fail again.

Twin engine overwater operations approval (ETOPS)for the 787 will not be forthcoming; the uncertainties are too great, and the root cause of the battery failures and fires, explosions date back six years to the initial tests of the battery and charging system at Boeing supplier Securaplane.

The current configuration is guaranteed to exacerbate any thermal problems with the battery, but the failure to reassess the charging system and it’s role in managing the battery is a fatal mistake; the battery itself, even if poorly designed, is harmless without the flawed charging system, which is supposed to keep the individual cells out of trouble and manage their charging state and temperatures within safe limits.
Finally, the acknowledged tendency for the batteries to self-immolate only leaves Boeing in need of a backup, should they fail-which is, of course, expected, hence the containment.
The failures of the FAA to verify ventilation of battery smoke has cost the administration terribly and represents a major blow to US credibility in aerospace.
It is not, and never was an engineering problem, just one of ethics.

ohh…every company have the responsibility to compensate the badly damaged new product as BOEING is doing.

Wait a minute here…it takes ‘hundreds of engineers’ to figure this thing out? That does not give me any kind of confidence that Boeing knows what it is doing.

Lithium batteries of several types have long been a thorn in the side of aircraft operators. Some years ago someone persuaded Canadian aviation authorities that they were safe: the authority not only mandated that all aircraft buy and instal a new design of ELT based on them, but also required that all other ELTs, including tail-fin models of superior design and survivability, be removed. Then, the lithium batteries started exploding in flight, and all the new ELTs had to be removed, leaving Canadian aircraft without any ELTs at all. All of this was at aircraft owners expense; none of the battery company, ELT companies, or governments paid a nickel towards our expenses.

Those who are ignorant of history are doomed to repeat it.

“I don’t think it fair to compare an ammo box – which was never designed to contain an explosion – to the design being proposed by the Boeing engineers…”

I agree. The intent was to show the force of a Li-ion battery ignition energy release and to imply a need to thoroughly test any containment apparatus.

A further observation: The Boeing engineers recognize the danger presented by venting the ignition to the outside of the aircraft.

In the amo box test, a large fireball erupted – most of the energy was released within what was estimated to be about 1/5 of a second.

The Boing engineers also are considering a venting tube. That was porovided in the amo box. It was ovewhelmed by the ignition and didn’t help at all.

“… why … can’t (Boeing) return to the same kind of batteries used in previous planes until the real problem(s) with lithium ion batteries is solved by the battery manufacturer?

NiCads (Used in earlier Boing aircfaft e.g., the 737) have about half the energy density of Li-Ions. It would require extensive redesign of the electrical system and a large weight penalty.

Airbus was able to revert to NiCads more easily, because their electrical system requires substantially less battery capacity.

The comment above by “flysafe” is on target. If the leaked reports are correct and the fix will insert ceramic insulation between the cells to prevent overheating of adjacent cells this could be like jumping from the fire into the frying pan. Heat generated within the cells must be dissipated or they will overheat, likely releasing flammable gases from the overheated electrolyte. Their heat must be transferred through a cooling medium to an external heat sink such as the walls of the battery box or they will overheat.

If the separation between the cells is large enough to accommodate both the new ceramic heat insulator and also a sufficiently wide passage so cooling air (or better yet a dry inert gas) can circulate throughout the box with sufficient motion against the cell walls on both sides of each ceramic separator to transfer heat from the cells to the walls of the new box, this precaution can be helpful.

But if there is insufficient space and the heat-insulators are jammed between the walls of adjacent cells, this could make matters worse by causing a hot cell to get even hotter because its heat can no longer be transferred to adjacent cells which are running cooler.

It would be a dumb fix if it could be like wrapping a dangerously hot cell with a blanket that causes it to get even hotter until it burns up. But never mind — the blankets wrapped around each of the other cells will protect them from those flames, even if their blankets make them get dangerously hot, too. Wouldn’t it be smarter to improve the cooling of all the cells to preclude the dangerous overheating of any single one?

@Schyte,

Building passenger jets is just a slightly more complicated process than making Greek feta. And besides, Boeing’s work force is unionized, just like in Greece. You expertise on these matters is built on real life experience no doubt.

The Dreamliner is a large plane. In order to keep voltage drops down, there must be quite a few battery banks distributed all over the plane. The risk is enormous as it is well known that lithium batteries have thermal runaway problems. This issue has been known for at least more than a decade now.

I hope that the FAA will not compromise safety and bend the rules.