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Lithium batteries in 787 may pose fire issues

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Member
Registered: May 2009
Posts: 479
Location: EFTO
Jeroen Hoppenbrouwers wrote
Rumours ... rumours ...

...among which "runaway battery in laptop in overhead crew rest area?"...

Solid fact: Shares dropped by 7 (later 4) %...

Martin
Moderator
Registered: May 2009
Posts: 2449
Location: KTMB
Latest rumour:

"The aircraft fire is unrelated to the batteries. This will be confirmed tomorrow in a boeing press conference. Fire is strongly believed to be as a result of galley overheat - failure of coffee heater trip switch which was left on.Burnt out much of the galley and area above causing deep damage to aft bh and rudder/elevator system. Aircraft sadly a write off - unless pride of hull loss/p.r dictates repair even if economically un-viable."

avherald.com, posted by "ba ground engineer" -- we'll see
Member
Registered: Jan 2010
Posts: 17
Sorry.
« Last edit by mabe54 on Mon, 15 Jul 2013 04:29:45 +0000. »
Member
Registered: Jul 2012
Posts: 17
Could it have been the lithium-mangan battery of the ELT transmitter? It's right next to the spot that burned. Plus Honeywell is now officially participating in the incident investigation.
Member
Registered: May 2009
Posts: 944
Here's an excerpt from a WSJ news article on the ELT transmitter theory:

http://online.wsj.com/article/SB10001424127887323848804578607910816833722.html#printMode

Investigators are examining the emergency locator transmitter on the Boeing Co. 787 as a potential cause or contributor to the fire that damaged an Ethiopian Airlines jet at Heathrow Airport last Friday, according to several people familiar with the inquiry.

The transmitter is made by Honeywell Inc. and located in the upper rear part of the 787, a location that's offering an early clue to investigators probing the incident, which came almost three months after the Dreamliner returned to commercial service following problems with its batteries.

U.K. investigators signaled over the weekend that battery problems hadn't triggered the Heathrow fire, and it remains unclear if the transmitter was the cause of the fire or a contributor to the damage of the aircraft. The device is designed to be activated in the event of a crash to help find the aircraft.

<snip>

The transmitter is installed in the ceiling above the rear doors of the Dreamliner and is at the center of the larger of two areas of fuselage skin damage seen on TV footage of the affected jet.

The devices are widely used on aircraft of all sizes, and are powered by a self-contained lithium-manganese battery, which have a less volatile history than the lithium-ion versions that caused problems on 787s earlier this year.
_______________
Best wishes,

Phil Bunch
Member
Registered: May 2009
Posts: 944
Here's a link to a news article on the most recent 787 fire. It contains a link to an official UK statement on the fire, and that statement says it appears unrelated to the primary backup lithium batteries:

http://www.businessweek.com/articles/2013-07-15/how-to-fix-a-hole-in-a-boeing-787#r=rss

The above article also discusses how one goes about repairing a composite airliner, which I found to be quite interesting.

The link to the UK statement is here:

http://www.aaib.gov.uk/cms_resources.cfm?file=/Boeing%20787-8%20ET-AOP%20Press%20Release.pdf

An interesting article on what the world's 787 pilots do when the 787 is grounded is here:

http://www.businessweek.com/articles/2013-03-14/with-boeings-787-grounded-pilots-find-other-stuff-to-do

I hadn't realized that they are usually not allowed to switch to another aircraft type if their primary type is grounded...
_______________
Best wishes,

Phil Bunch
Member
Registered: May 2009
Posts: 944
_______________
Best wishes,

Phil Bunch
Moderator
Registered: May 2009
Posts: 2449
Location: KTMB
Member
Registered: May 2009
Posts: 944
_______________
Best wishes,

Phil Bunch
Member
Registered: Jan 2010
Posts: 17
Signs of the times we live in. PR reactions supersede sound engineering practices, common sense. careful analysis, science and everything else.

:x

Cheers,
Member
Registered: May 2009
Posts: 149
Re above: I seem to remember reports of iPhones getting way hot also (mine still gets really uncomfortably warm at time, particularly at low battery charge levels). Would be interesting if the whole "pack more and more energy density into smaller and lighter devices" problem has some limits for a lot of things. Moore's law can't apply indefinitely to all parts of these systems at the same time! Maybe this will spark a new wave of spontaneous human combustion stories in the tabloids.

Cheers,
Torrence

Edit - some of these reports imply that these Honeywell ELTs are in lots and lots of ships other than 787's. Maybe Boeing just got unlucky? Unless they insisted on some mods ...
T
Moderator
Registered: May 2009
Posts: 2449
Location: KTMB
787 mods.

Being the Electric Jet, one of the things that a 787 does differently is the circuit breaker stuff. The 787 does not have bi-metal CBs on the flight deck. Instead, the actual breakers are remote, and as far as I know solid-state. They are linked to pseudo-breakers on the flight deck so pilots can still selectively disable systems and see what popped due to overload.

One of the obvious things in which a solid-state breaker is different from a bi-metal breaker is response time. Classic avionics that draw 1 amp in operation may easily draw 10 amps for 10 ms during powerup (current inrush) and a bi-metal breaker does not even blink at this. However, a solid-state breaker trips after 1 ms into the 10 amps inrush.

We had to fix this for our Iridium satcom unit which, we are proud to say, flew on the 787 test fleet as a backup communication device (FANS and all).

It may be that this kind of fix (diodes and resistors over the main power capacitors) has screwed up something stupid in the ELT. A blind guess, but the 787 does require different equipment than any other jet at this moment.


Hoppie
Member
Registered: May 2009
Posts: 944
_______________
Best wishes,

Phil Bunch
Moderator
Registered: May 2009
Posts: 2449
Location: KTMB
http://www.skybrary.aero/index.php/B788,_London_Heathrow_UK,_2013_%28FIRE_AW%29
Member
Registered: Jul 2012
Posts: 17
So the FAA released their AD. Battery and cable checks for all ELTs onboard US 787.
ANA said today it found two minor irregularities with ELT-cable insulations after checks and exchanged two of their 787-ELTs.

PS: United found another one
« Last edit by Sese on Sat, 27 Jul 2013 12:52:37 +0000. »
Member
Registered: Jan 2010
Posts: 17
http://www.skybrary.aero/bookshelf/books/2078.pdf

Like carrying grenades with loosely and easily dropping pins.

What a nightmare.

Cheers,
Member
Registered: Jan 2010
Posts: 17
http://au.news.yahoo.com/thewest/a/-/world/18165788/qatar-grounds-a-787-as-glitches-pile-up-on-boeing-jet/

Cheers,
Member
Registered: May 2009
Posts: 497
Still not out of the woods yet:

http://edition.cnn.com/2014/01/14/travel/787-dreamliner/index.html?hpt=hp_t1

http://avherald.com/h?article=45c377c5&opt=0

Jeroen
Member
Registered: Jul 2012
Posts: 17
What is practically happening, if a 787 should lose it's main battery inflight? What systems and functions are affected and what is left please?

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