Lithium batteries in 787 may pose fire issues

[Jeroen Hoppenbrouwers]

http://www.skybrary.aero/index.php/Boeing_787_Battery_System_Modifications

"The NTSB and the JTSB are still investigating the origin of the battery overheating events which occurred to two different aircraft within 9 days of each other in January 2013. However, the FAA has considered a Boeing proposal for modifications to the battery system and has approved it as a basis for testing a solution which will allow the FAA to sanction a return of the aircraft type to service."



"Jim, when the lithium crystals start cracking, we'll have to eject the core."



Hoppie

[mabe54]

I think everybody is fixed in the Batteries and they are forgetting the role play by the Battery Charging System in this mess. Also, Boeing's solutions seem tobe aimed to minimize and contain damages to the Batteries casing in case of future catastrophic failures. It doesn't inspire confidence. Not good.

Me think,

MAB

[Jeroen Hoppenbrouwers]

It feels like Boeing has firmly committed "at all costs" to have Li-Ion batteries in the 787. I understand some of the major improvements in energy/weight ratio and other critical physical/electrical phenomena that Li-Ion brings over NiCd. These surely make for an important part of the 'dream'. Apparently, Boeing (at least some part of it, apparently a powerful part) has determined that this part of the dream must, at all costs, be carried forward.

There are significant implications throughout the aircraft if the batteries would be replaced by a different system. It may still put out 28V but nearly everything else would be different. An airliner is not just a bunch of power consumers on a common bus. A redesign and recertification of even a small subsystem of an airliner is a nightmare. Boeing must fix the battery subsystem and leave everything else untouched. This may explain their focus on getting it right.

Nobody can change the way how Li-Ion batteries work. The world knows that this technology has its risks. We can mitigate risks -- but not eradicate them. A new charger, a new charge/discharge monitor, new temperature sensors, all of these can attempt to better manage the battery operation -- but it remains a risky technology. And when (not if, when) it fails, it will be a significant risk to flight safety. This demands heavyweight (literally) safeguards, firewalls in the literal sense of the word, to contain the expected battery cell failure. And at the same time, this battery powers an airliner. You cannot just remove the battery from the live system when you think it is going berzerk. A battery is a crucial part of an airliner's backup systems. There will be cases where the captain prefers to set the battery on fire in order to keep the airliner alive.

As long as Li-Ion is not fully understood (and it isn't, despite four decades of experience), and as long as there is no better technology available that is at least as understood, there is little Boeing can do except push on.

A scary situation, sure. But hey, free enterprise, right? Things only get better by taking risks and making an educated bet on the benefits it could bring if successful. This implies that bets gone wrong will hurt you. If you cannot take the pain, and there is no government to help you out, well...

I wonder whether Boeing would be too big to fail...?


Hoppie

[Sese]

Okay, let's assume the batteries could now safely "overheat" without any further damage to the aircraft. But you might still lose the main battery through a fire. So by that wouldn't you lose your most critical infrastructure? What would this mean for the operations (engine and system failures, standby power, brakes), for ETOPS and for public perception? Can we really go on without knowing the root cause?

[mabe54]

If you cannot take the pain, and there is no government to help you out, well...

Hoppie

Forgetting the Dreamliner and Boeing for a second, the line above gave me comfort about not being the only one noticing profound changes in the geopolitics of the third ball in the Solar System. After 50,000 years everything changes to stay the same.  

Oh well...

MAB

[Phil Bunch]

Here's another update of the 787's status and tests, etc:

http://www.bloomberg.com/news/2013-04-05/boeing-says-787-battery-ground-tests-done-as-flight-nears.html

If there are any more serious in-flight problems with the revised lithium battery systems after the FAA hypothetically approves the 787 for some sort of quick "return to flight" status, Boeing's decision to stick with lithium batteries would become a major disaster for the 787 program.  I even wonder if it would seriously harm the 787 permanently, similar to what I recall about the DC-10 and its engine mount problems.  It might not take much to make the public and airlines become averse to an airliner, whether fully justified or not.  

I continue to be amazed that Boeing has stayed with the lithium batteries instead of a NiCd retrofit.  

It will also be interesting to see if the FAA goes along passively with Boeing's attempts to expedite the revised battery design through the FAA and other regulatory approvals.  I also can't imagine the FAA doing that, but who knows given the politics that the USA has these days...

[Avi]

I wonder if Boeing, after getting the B787 back into the air, will work on "plan B" in case there will be problems again with the new battery design so they will be able to give an answer in a very short time (or it might be the end).

[Phil Bunch]

The NY Times has some interesting comments in their latest update:

http://www.nytimes.com/2013/04/06/business/boeing-completes-test-787-flight.html?adxnnl=1&ref=todayspaper&adxnnlx=1365259011-+yFMthMLoNDPF68LojMTbQ

Below is an excerpt:

"The National Transportation Safety Board, which has been investigating a battery fire on a 787 parked in Boston on Jan. 7, plans to hold a public forum on Thursday and Friday on transportation uses of lithium-ion batteries, which are more volatile than traditional designs. On April 23 and 24, it will hold a hearing on its investigation into the Boston fire and the deficiencies in the F.A.A.'s initial review of the batteries several years ago.

Those hearings could add to a sense of political caution at the F.A.A., though its engineers have said they believe that Boeing's changes are working. "And this is all complicated by the fact that Boeing doubled down on this approach and does not have a backup plan," Mr. Aboulafia said. "

----------------------
 I was surprised to read the Times' assertion that Boeing has no backup plan in case things don't progress with respect to their new lithium battery system.  The Times is usually very good about fact checking, etc.  This is surprising to me since AFAIK they still have no idea why multiple batteries caught fire before the 787 was grounded.  How can they claim to have fixed the problem with a new battery design when they don't know what went wrong with the previous in-flight battery fires?  I also wonder how long it might take to get a new lithium-based system into full, FAA-approved production, under these circumstances?  It's one thing to build a single prototype and quite another to start making them in volume and to obtain full FAA certification, even ignoring the "unknown battery fire cause" issues.

[Jeroen D]

Looks like the Dreamliner will be flying again soon!

http://www.bbc.co.uk/news/technology-22226843

[Jeroen Hoppenbrouwers]

Like waking up with a headache ...

[Phil Bunch]

A few more details here:

http://www.nytimes.com/2013/04/20/business/faa-endorses-boeing-remedy-for-787-battery.html?ref=todayspaper&pagewanted=print

But, with no proven cause for the battery failures, will owners and passengers share Boeing's enthusiasm for their new design?

[Phil Bunch]

I was surprised to read that the FAA has also approved ETOPS, as described here:

Some additional details here:

http://www.bloomberg.com/news/2013-04-19/faa-approves-boeing-787-battery-fix-allowing-flight-resumptions.html

Excerpt:  

"Modifications to the planes began yesterday, and the U.S. Federal Aviation Administration said it will issue a directive next week to let flights resume once the battery fixes are made. The 787 will still be allowed to travel as far as 180 minutes from the nearest airport, enabling it to be used on over-ocean routes, said Laura Brown, an FAA spokeswoman. "

[Jeroen Hoppenbrouwers]

ETOPS is a statistical game and I think (don't know for sure) that the battery problems, which did not happen in ETOPS airspace, did not influence this game.

Note that ETOPS is mostly if not only about engines (Twin Engine in the acronym). If you don't shutdown an engine in flight, you have no ETOPS problem.

Probably all the tens of thousands of hours of test flights were carefully designed to be ETOPS-qualifying and therefore the 787 has been building ETOPS score over the years leading to deployment?


Hoppie

[Balt]

ETOPS does not only refer to single engine flight time limitations, it also comprises crew procedures, engineering and flight procedures. And these days ETOPS also comprises airplanes with more than two engines.

Even without being familiar with the electrical design of the 787 this battery issue might very well impact ETOPS. Just consider this: Power must be fed to all essential electrical systems. The Li battery obviously is a rather central component to all things electrical on this airplane, so a backup power solution must be present which powers all essentials for the remainder of the flight. If backup powers the systems for less than whatever ETOPS rating you're going for, you have no ETOPS compliance.

Cheers

- Balt

[John Golin]

My understanding was the battery wasn't of use in the air, only on the ground?  It's the APU battery for starting the APU in the absence of other power sources.

There are 3 other sources in the air - engine 1, engine 2, and RAT?

Therefore 'loss' of battery / charging (per se) is not be relevant to ETOPS?

But then I got all that from PPRuNe so who knows...

From the 2010 study guide, the Boeing MMEL says the APU battery can be inop (or maybe removed?) if all engine VFSGs are OK and you stay within ETOPS 180.

[Balt]

Then perhaps they just fire proofed the battery bay to meet ETOPS 180 so it lasts for 3 hours before it melts through the plastic fuselage and sets the remainder of the plane on fire...  :twisted: Just wrap it into sufficiently many layers of duct tape...

[Jeroen Hoppenbrouwers]

No, it is TWO equal batteries, one for APU (and other things), one for the main systems. Without a battery most systems may have a problem. Boeing may have altered the system since the 744 but switching off the battery in mid-flight will usually give interesting effects.


Hoppie

[Balt]

The 744 adheres to the dark cockpit philosophy. With the main battery down, the 787 adheres to the really dark cockpit philosophy...

[Jeroen D]

Another "in depth" article on the batteries:

http://www.bbc.co.uk/news/business-22251756

Quote:
The two lithium-ion batteries are not used when the 787 is in flight.
Instead they are operational when the plane is on the ground and its engines are not turned on, and are used to power the aircraft's brakes and lights.
Unquote:

So these batteries are only used on the ground, just in case you wondered. So a lot of fuss about nothing really. Plane is fine, the aviation industry often doesn't find Root Causes to problems, fires etc.

Whatever malfunctions, just put it in a stainless steel box and we'll be fine.  :lol:

It really makes you wonder what all the fuss was about???  :roll:

Jeroen

[mabe54]

I still think they should keep a watchful eye on the Battery Charges. Something might be weirdly funky about them. Do not have overly confidence in their maker either.  

Cheers,