Another 787 Fire this time at LHR

[UALdave]

Next Monday's Aviation Week has a two page story on this failure. Highlights are:

The fire did not burn through the skin but was hot enough to char the exterior painted surface.

The composite is more resistant to fire than aluminum.

Boeing plans to repair the aircraft (patch or new tail section) but write off is still possible. Boeing has developed repair procedures but did not expect to use them so soon.

The 787 has two ELTs (one fed and one aft) plus more in life rafts.

That's interesting-I wonder why it happened in the aft ELT? They both use the same battery type.

[Dispatch Dog]

I use a big range of different types of batteries, usually at the extremes of performance. Every now and again, one fails. The more spectacular failures are indeed heat runaway and the odd LiPo that goes pop!

Not great when I lose an airframe, but no one gets hurt. I always worried about the use of these things in real aircraft and just assumed that clever folk had figured out how to make them as reliable as any other component on part 121 aircraft.

Charging is usually the time when things go pop while high current use triggers the heat runaway. So wondering exactly what went wrong on this one.

Fire resilient fuselage is good news, especially for structural integrity. Doesn't make it easy for fire services and I wonder how hard it is to break through to access fires. Lots of interesting scenarios and again, wondering what it will do to survivability.

[tsv]

Riddle of the Day.

Q. What's the difference between a Super Jet and a 787?

A. One crashes, the other Burns.

[Highkeas]

..........Charging is usually the time when things go pop while high current use triggers the heat runaway. So wondering exactly what went wrong on this one.
....................

From what I have read the ELTs do not use rechargeable batteries.
What triggers an ELT to start emmitting signals?

[brianw999]

From what I have read the ELTs do not use rechargeable batteries.
What triggers an ELT to start emmitting signals?

As far as I know they are triggered by immersion in water. There may be other criteria as well though.

[3WE]

As far as I know they are triggered by immersion in water. There may be other criteria as well though.

Don't forget: Sudden deceleration.

[Black Ram]

There is also a "self-test" activation, which triggers it for testing purposes.

[snydersnapshots]

FAA ELT Airworthiness Directive

Here's the latest: The FAA has issued an Airworthiness Directive requiring airlines to ensure that the ELT batteries are safe:

http://www.faa.gov/news/press_releas...m?newsId=14233

[Highkeas]

In the last day or so an Air India 787 reported that a galley oven was smoking and the cabin crew responded by removing power and using a fire extinguiser.
This made me wonder whether Boeing switched to a different or thinner insulation on 787 wiring in order to save weight.

(Of course the oven smoke might have been due to a meal container or other item melting or burning.)

[ZedFear]

Here's the latest: The FAA has issued an Airworthiness Directive requiring airlines to ensure that the ELT batteries are safe:

http://www.faa.gov/news/press_releas...m?newsId=14233

That appears to me to be the AD from the ANA flight.

[UALdave]

In the FAA press release on July 20th, the FAA said that they don't require jets like the 787 to have ELTs installed-why not?

[Highkeas]

This may be the ELT used on the 787

http://www51.honeywell.com/aero/common/documents/myaerospacecatalog-documents/BA_brochures-documents/RESCU_406_AFN_ELT.pdf

Could it be, for the LHR incident, that the remote test unit was left turned on and the wires connecting it to the ELT melted?

[Joe H]

This may be the ELT used on the 787

http://www51.honeywell.com/aero/common/documents/myaerospacecatalog-documents/BA_brochures-documents/RESCU_406_AFN_ELT.pdf

Could it be, for the LHR incident, that the remote test unit was left turned on and the wires connecting it to the ELT melted?

The remote test simply triggers a TEST.. nothing more. A sginal is sent, the unit does a test, then goes back to standby. All power is from internal batteries.
Hence, I very much doubt your theory sir.
However, heat from external cables could well be the cause, we will have to await the outcome.
Maybe we shoud start calling it the Flarebus or Screamliner ???

[EconomyClass]

Casual question: Does anyone check the ELT battery before each flight. It is one battery you'd want fresh.

[B757300]

Boeing is now recommending that operators of the 717, 737NG, 747-400, 767 and 777 which use the Honeywell ETL to inspect or remove the device from the aircraft.