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-   -   Ethiopean 787 fire at Heathrow (https://www.pprune.org/engineers-technicians/518971-ethiopean-787-fire-heathrow.html)

fenland787 19th July 2013 10:52


lightning strike.

An aluminum body would have safely grounded the energy around the skin.

the composite body allowed it through and into the ELT, setting it on fire.
Airplane had been on the ground for eight hours, no reports of lightning anywhere near LHR

E_S_P 19th July 2013 10:53

Speed of Sound
 
SoS

Given the almost faultless history of this device, installation/location of this device may be where the AAIB should be concentrating their efforts.
I have been having the same thoughts, as I 'believe' that ET do not have the rear crew rest areas installed on the 787 at the rear, so straight away there would be differences from standard production types.

I am presuming that all of the original services that would have fed into this rest area would still be roughly in that location, albeit disconnected and (hopefully) all safely capped off and secured. The internal finishes and fittings would therefore also be nonstandard in this area. So could this combination cause some kind of detrimental enviromental change in the area where the ELT is located?

Given the number of ELT's in use its either the ulimate s*ds law that this has happened on a 787, or is there something specific about this ET version?

Is it known if there are any other operators using this configuration?

Speed of Sound 19th July 2013 11:03

deggers316
 

that this event was in the tail section behind the bulk head (prob wrong on this)
The ELT is located FORWARD of the rear pressure bulkhead. That is why they were able to tackle the fire from the rear cabin.

If this had been in flight then most likely the flight crew would get down quickly enough to avoid explosive decompression once the fire burned through to the outside. From that point on, aggressive use of the rudder and elevator would need to be avoided as the tail section would more than likely distort as a result of fire/heat damage rather than just fall off as happened with JAL 123.

Speed of Sound 19th July 2013 11:54

phil
 

What equipment does the cabin crew have to pull down ceiling panels to get to the location, whilst in dense (?) smoke ?
A fire axe and a portable oxygen mask but nothing to protect their heads from falling debris some of which may be burning. :(

It makes me shudder to think of some poor brave soul or souls attempting this in the knowledge that if they are not successful they would need to not only retreat but evacuate passengers forward of this position, all while strapped in for an emergency descent possibly with O2 masks deployed.

In the absence of a final report, we have to assume that this could just as easily have happened in the air.

Anyone working for Boeing PR having a moan about their bad luck needs to catch themselves on.

Pittsextra 19th July 2013 12:13

What a mess:-


Boeing 787 Safety Move Splits Airline Action on Honeywell Beacon
By Robert Wall and Chris Cooper


July 19 (Bloomberg) -- Boeing Co. 787 operators are grappling with conflicting regulatory guidance after U.K. safety authorities called for the deactivation of an emergency beacon linked to a fire on a Dreamliner at Heathrow airport last week.
U.K. charter carrier Thomson Airways removed the Honeywell International Inc. locator within hours, while Japan Airlines Co. has inspected the device but faces a local legal requirement to have it on board, according to spokesman Kazunori Kidosaki. Poland’s LOT said it has made checks and the part is “fine.”
Implementing the recommendation to disable the beacon --which signals a plane’s position after a crash -- may need an airworthiness directive, according to Dominique Fouda, a spokesman for the Cologne-based European Aviation Safety Agency. The emergency locator transmitter is part of a minimum equipment list, though can be made inoperable in some conditions, he said.
“Under European regulations, ELTs can be temporarily deactivated for maintenance while the aircraft continues to fly,” added Richard Taylor, spokesman for the U.K. Civil Aviation Authority, in an e-mail. “The temporary removal can be extended for as long as necessary.”
The U.K. Air Accidents Investigation Branch yesterday urged the U.S. Federal Aviation Administration to initiate action for the deactivation of the Honeywell part after determining it was the only system in the area of the fire on an Ethiopian Airlines Enterprise 787 on July 12, adding that the event “could pose a significant concern” had it occurred with the plane airborne.
Ministry Decree
ANA Holdings Inc., the biggest 787 operator, hasn’t removed the devices because Japanese aviation law requires them aboard, said Tokyo-based spokeswoman Megumi Tezuka. If the FAA, the certification
Boeing 787 Safety Move Splits Airline Action on Honeywell Beacon

authority for the Dreamliner, ordered the removal of the components and Boeing issued a directive it would do so once Japan’s transport ministry published a decree, she said.
The FAA is reviewing the U.K. report “to determine the appropriate action,” spokesman Lynn Lunsford said yesterday.
Boeing would issue instructions to airlines about how to remove the beacon and provide assistance as needed, said Doug Alder, a spokesman for the Chicago-based company. The emergency locator can be removed quickly and won’t idle the 68-jet fleet.
LOT Polish Airlines SA, the first European carrier to get the 787, “anticipated the situation and we had already checked emergency locator beacons on our 787s before the U.K. safety board recommendation,” spokesman Robert Moren said by phone. The beacons “are fine, so we are not deactivating them.”
Visual Checks
United Continental Holdings Inc., the sole U.S. operator of the composite-plastic plane, has performed visual checks of the transmitters on its six 787s “with no findings,” Christen David, a spokeswoman for the Chicago-based company, said by e-mail.
India’s aviation safety regulator will make a decision after Air India Ltd. -- which operates seven 787s -- receives a directive from Boeing, Arun Mishra, director general of civil aviation, said in a phone interview. Rohit Nandan, the carrier’s chairman, didn’t immediately answer calls and a text message.
Indian rules also stipulate that all aircraft be fitted with an ELT device that meets FAA standards. Only aircraft used for training or research are exempt, according to the rules published on the aviation regulator’s website.
Norwegian Air Shuttle AS, which leases Dreamliners from International Air Finance Corp., said it’s in “close contact” with Boeing and civil aviation authorities. “We will of course follow all the instructions that we are given,” spokeswoman Astrid Mannion said by e-mail today.
Qatar Airways Ltd., the only Middle Eastern 787 operator, declined to comment.
The ELT beacon, using lithium-batteries, is suspect because it’s the only power source in the area of the fire, though investigators are still probing whether the device combusted or was set alight by an outside source. The incident is the first involving more than 6,000 such Honeywell devices, the AAIB said.

meekmok 19th July 2013 12:21


METAR says the temperature at LHR was 25C at the time the alarm was raised. Given that heat rises, anyone want to hazard a guess at how warm it becomes just under the crown of a non-insulated fuselage skin which has been baking for the entire day?
25 degrees C is baking? The 787 underwent flight testing in Phoenix and Yuma, where it would of been 45+ every day.

MacBoero 19th July 2013 12:23


Originally Posted by Jazz Hands
METAR says the temperature at LHR was 25C at the time the alarm was raised. Given that heat rises, anyone want to hazard a guess at how warm it becomes just under the crown of a non-insulated fuselage skin which has been baking for the entire day?

And does anyone else leave their 787s outside for a similar time, in similar heat, or do they return to the cool high altitude too regularly?

According this Honeywell Rescu 406 AFN2 Brochure, the storage temperature range of the ELT is -55 to +85 Celsius. I could well imagine it getting close to that if not higher if in direct sunlight for long enough. The upper end of the operating temperature range is specified to be lower, 55 Celsius, which I would have thought easily achievable.

Various studies on car interior temperatures, where vehicles are closed up and left in the sun show startling high temperatures. Temperatures for the air alone can be as high as 50 Celsius. Surfaces (especially dark surfaces) inside vehicles tend to be much hotter, as this is the source of heat for warming the air. Dashboards are known to reach about 100 Celsius.

If there is any comparison here, without insulation for the ELT, I would have thought the installation site unsuitable in this instance.

nitpicker330 19th July 2013 12:41

Wouldn't most of the heat in a car be from direct sun through the glass windows?? Surely through a fuselage wouldn't get that hot ever???

fenland787 19th July 2013 12:43


25 degrees C is baking? The 787 underwent flight testing in Phoenix and Yuma, where it would of been 45+ every day
And Ethiopia ain't exactly cold? "Danakil Desert is about 125 metres below sea level and the hottest region in Ethiopia where the temperature climbs up to 50 degree Celsius"

aeromech3 19th July 2013 12:53

Speed of Sound & Phil:- Smoke Hoods should be available whereas a fire axe is only mandated by some authorities, if I recall correctly.
Perhaps there is a study on how carbon fibre composites dissipate heat by conduction as compared to aluminium which does it very well.

MacBoero 19th July 2013 12:59

The outside temperature has some effect, but the primary source of energy would be from the sunlight. If there is no cooling breeze either, that could exacerbate the problem.

The heating effect on cars is not down to the glass. From what I have read, it would appear that the presence of glass merely affects the rate of heat rise. One compared cars, buses and vans. The van reached the same temperature as the car, it just took longer.

I also wouldn't expect the ELT to have problems the first time it is exposed to temperatures outside its specifications. It might need several excursions outside the permitted range, before problems can occur. If indeed this is what caused it in the first place.

Speed of Sound 19th July 2013 13:00

Temperature.
 
Just trying to think outside the box here, but does anyone know where this aircraft was parked during its grounding earlier in the year?

If it was in one, single location, it may have been subjected to three months of regular heat/cooling cycles which may have had a detrimental effect on the folded cathodes inside one of the cells, especially if they were still switched on during the period.

Yes, I know that this happens to most aircraft on a daily basis but we need to look for something which sets this particular device apart from all the others and a regular very hot days followed by very cold nights cycle may have played some part in degrading the battery.

island_airphoto 19th July 2013 14:07

Has any PLB/ELT/EPIRB ever - in the entire history of these devices - burned up and amaged an an airplane, boat or other vehicle :confused:

To me this just does not seem all that likely.

fenland787 19th July 2013 14:14

I certainly wouldn't rule out temperature as a cause and I don't have numbers but I still suspect the difference in solar heating between composite and aluminum will not be vast and given the number of these in service (over 6,000?) if there was a marginal temperature effect we would have seen it by now in something else.

I'm guessing of course but suspect it will turn to be either really bad luck, some installation issue or - and my favorite - that the version of this ELT used in the 787 has been 'tweaked' in some way that has left it vulnerable.

MurphyWasRight 19th July 2013 14:28


... the difference in solar heating between composite and aluminum will not be vast and given the number of these in service (over 6,000?) if there was a marginal temperature effect we would have seen it by now in something else.
But how many of the others sat baking in a dessert for 3 months?

Another difference could be what happens if a battery does go, do the aluminum instalations have a heat sink effect and or nothing flammable nearby?

It seems that something else had to have caught fire to cause the level of damage seen.

It is also possible that protective insulation (if pressent) around the ELT allowed higher temps to devlope from a battery "thermal event".

cappt 19th July 2013 14:31

Grounded 787's sat out in the Houston TX sun for several months recently, no ELT fires.

MacBoero 19th July 2013 14:45

But there has been talk that the Ethiopean plane is different to the standard layout in this area, i.e. the crew compartment is not fitted. This may have changed the way the ELT is mounted/contained in this aircraft. Is it now more enclosed than in other 787's, thus reducing the movement of free air around the ELT? Was any insulation omitted due the absence of the crew compartment, thus reducing or removing any protection the ELT might have normally had?

MurphyWasRight 19th July 2013 14:51


Grounded 787' sat out in the Houston TX sun for several months recently, no ELT fires.
- yet -

Also not as hot and I as I recall the incident 787 was first back in service.

That said even if the "hot soak" is a factor worst case it should have caused a safe battery fail not a fire.

The real question (assuming the battery is the initiater not victim) is why a fire started.

Speed of Sound 19th July 2013 15:46


Grounded 787' sat out in the Houston TX sun for several months recently, no ELT fires.
No but that doesn't mean no ELT battery damage.

If I was Honeywell I'd have that unit swapped out and have the batteries back in the lab for a thorough examination.

Volume 19th July 2013 16:03


Post 502
Fancher said "a good design fix" to dehumidify the interior is being installed and will be tested when the Dreamliners resume flying.
Is the "other aircraft system in the vicinity which, with the aircraft unpowered, [...] capable of initiating a fire in the area of the heat damage" a zonal dryer ?
Those are well known for overheating...

SLF3 19th July 2013 16:28

Straws in the wind....
 
From previous posts:
- 'Rainliner'
- Wiring thinly coated with non abrasion resistant Teflon
- AAIB request to inert the ELT only applies to the 787 (ie, believe problem is 787 specific and outside the ELT)
- Non standard installation (no crew rest area) - 'unused' wiring

If the problem is moisture and / or abraded wiring leading to a short it would be very bad news for Boeing - because it potentially raises generic questions about the 787 design that are not localised to the area around the ELT.

syseng68k 19th July 2013 17:00

Hi,

Having worked through this thread, cause of fire ranging from coffee
maker to elt, i'm wondering just what we are being fed here.

As far as I can see, the elt batteries are completely encased in
thick aluminium and the batteries also have inline fuses to limit the
current to a safe level in the case of a short circuit, so how could
they ever cause a fire ?.

Some of the most reliable technology, over millions of hours with no
significant event and suddenly we have a major fire in a very new a/c
with a significant history of problems and malfunction.

Sorry, but I just don't believe in such coincidences :-(...

aeromech3 19th July 2013 18:10

I would assume that the mounting of the ELT battery/transmitter would be on a small rack and that only the antenna itself would be direct skin mounting, all be it with a gasket!

Clipper7 19th July 2013 19:06

Airbus' John Leahy: Boeing 787 Unreliable, Immature Aircraft
 
Haven't seen this gem posted here:


TOULOUSE: A senior Airbus executive hit out at rival Boeing's troubled Dreamliner on Friday, saying the aircraft was clearly not reliable and suggested it was rushed to market.

"It's pretty obvious that this airplane is not reliable and does not have mature systems," Airbus sales chief John Leahy told reporters at a ceremony to mark the 1,000th delivery of the company's A330 plane, to Hong Kong airline Cathay Pacific.

"You can keep it flying but it's going to cost you a lot of maintenance," Leahy said, in the first comments by Airbus management about the Dreamliner's difficulties.

"What they've got is an architecture that is not mature and that will eventually become mature. It's going to take a lot of time, a lot of money, a lot of cancelled flights. And maybe redesign quite a few systems onboard."


Airbus executive says Dreamliner 'not reliable' - The Economic Times

fenland787 19th July 2013 19:14


TOULOUSE: A senior Airbus executive hit out at rival Boeing's troubled Dreamliner on Friday
What insightful and helpful comments from someone who, I presume, considers he will not be perceived as having a vested interest in knocking Boeing and it's products!

amicus 19th July 2013 20:40

Speed of sound,
Codswallop, total and utter codswallop.

amicus 19th July 2013 20:43

Jazz Hands,
Around 150=-160 F

amicus 19th July 2013 20:47

Speed of Sound,
And where and doing what are the totally unprotected SLF in all this?

amicus 19th July 2013 20:59

Aeromech3
Good comment, but what are all the SLF doing in all this other than breathing toxic carbon monoxide, cyanide and a host of 90 other toxic nasties in dense smoke via FST or just watching IFE in spite of dense FST smoke with no protection whatsoever?
The whole onboard fire fighting a critical internal FST fire just doesn't wash, sorry. And RIP to all onboard in that event.

syseng68k 19th July 2013 21:08

Does seem to burn quite easily and am quite surprised that some sort of
inerting or halon extinguishant wasn't mandatory for critical areas of
this airfix a/c...

BOAC 19th July 2013 21:17

In flight I suspect one might have to consider using the ocean to put it out.

HairOfTheDog 19th July 2013 21:31

No Photos?
 
Can anyone explain why there have been no photos of the inside damage? There are many who could have legitimate comments that might help understand what happened with photos.

awblain 19th July 2013 21:36

If it was "burning" batteries in the beacon that started the fire, and they were still involved when the fire crew arrived, then it's unlikely that anything short of cooling the batteries below their reaction temperature would stop the energy release. I understand that the failed batteries do not require external oxygen to start, or continue, to release heat. Presumably halon will quickly stop the burning of the aircraft structure in air, although unless it's also cooled, than the fuselage would presumably reignite if it stays hot and the halon drifts away.

cappt 19th July 2013 22:18

I agree something here doesn't pass the smell test and is being kept quiet. Any fire investigator worth their salt can look over the aft galley and tell you if the fire started in the trash can, coffee pot or other suspected working area the crew may have utilized. This 406ELT has been used on several other aircraft for years with no history of overheating. Also the ELT battery is not of sufficient size to burn hot for more than a couple minutes if it shorted or puffed like lipo's will do when overheated. Can this ELT be activated from the cockpit like other aircraft? if so then it has a wire harness attached. I think the public and crews working this aircraft have reason to want an answer.

mm43 19th July 2013 22:18

@syseng68k

Sorry, but I just don't believe in such coincidences
Something doesn't add up. Okay, the AAIB have concerns surrounding the evidence they seen about the actual ignition source. I suspect the Li batteries in the ELT may or may not be to blame. Forensic examination of the battery housing should establish relatively quickly whether an external heat source was involved. Likewise if the heat generated by a battery short radiated beyond the casing etc..

Methinks the AAIB is taking a very cautious approach.

syseng68k 19th July 2013 22:22

One thing to remember is that the elt batteries have only a fraction
of the capacity of the main a/c batteries, have a very different
chemistry and wouldn't suffer from the same problems in service.
Such batteries are also often current limited by design. ie: They
would be very unlikely to have enough available energy to burn
through the metal enclosure.

I had to source some long life lithium batteries for a project some
years ago. They were Lithium Thionyl Chloride chemistry, C cell sized
cell, with a high 19.5A/hours rating, but only at very low drain
current. They were rated for 125 C service, with welded stainless steel
outer case. Also found some other Lithium cells during the search that
were rated at over 200C, for applications such as deep oil well data
logging.

I find it hard to belive that these batteries could have caused the
fire, but we just have to wait and see...

Huck 19th July 2013 22:45

It'd be hard to take this thing on an ETOPS leg right now....

overstress 19th July 2013 22:58


Methinks the AAIB is taking a very cautious approach.
They can do little else.

If you issue an edict to ground an aircraft without knowing precisely why, how do you then release it to fly again?

kenneth house 19th July 2013 23:20

a good primer on battery failure
 
that explains where the oxygen originates that can cause such a strong fire that halon cannot extinguish.

Lithium Battery Failures

RetiredF4 19th July 2013 23:34

Which ELT RESCU 406® AFN2?
 
honeywell

There are two ELt 406, the new one RESCU 406® AFN2 more than 50% lighter than the older RESCU 406® AFN.
The AFN2 has two cells, the old AFN had 5 cells. Now i'm wondering, if really already 6000 devices of the new one with only two cells are in operation or if that number is related to all 406 ELt's with two and 5 cells.

And i'm further wondering, if this 2 cell design, which saves a 4.3 lbs in weight might have some influence onthe happening.


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