Ethiopian Boeing 787 on fire at gate in London Heathrow

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Flanker2
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Re: Ethiopian Boeing 787 on fire at gate in London Heathrow

Post by Flanker2 »

It's not quite a relief for Boeing:
If the ELT is the problem, then the ELT's need to be replaced with new ones that are fine.
Since no aircraft can fly without ELT's, this means that pending a replacement solution and certification, the aircraft would have to be grounded again.

I think that it's a wonder that they didn't ground them again pending the result of the investigation. An aircraft that can spontaneously catch fire shouldn't be allowed to fly over the ocean hours away from land...

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sn26567
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Re: Ethiopian Boeing 787 on fire at gate in London Heathrow

Post by sn26567 »

As mentioned before, more than 4000 such ELTs have been installed for many years on various types of planes without serious incidents. You don't ground an aircraft for a single incident. Even for the Li-ion batteries of the 787, two incidents were needed in a short period of time before authorities decided the grounding.

I think that Boeing is safe this time. Honeywell probably less so.

Boeing will even learn from the incident: for the first time a carbon fibre composite will have to be repaired, and that's the real challenge.
André
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Flanker2
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Re: Ethiopian Boeing 787 on fire at gate in London Heathrow

Post by Flanker2 »

I beg to differ.

Until it's verified that it's the exact same ELT and not a variant of an existing type, and this is what caused an aircraft to lose it structural integrity, I don't think that Boeing is safe at all.

I also don't believe that a small unit as an ELT can cause the damage that we see here, not even in the worst short-circuiting scenario's. If so, and if it indeed is the same ELT installed on other aircraft, it must be very very very unlucky that it just happened to do that on a B787.

An aircraft isn't supposed to be connected to ground power while parked for 12 hours, unless there is someone watching it and doing something on or around it that requires electricity to be fed into the systems. But small independent batteries integrated into systems don't have enough power nor voltage to generate a powerful enough source of heat to ignite the fire-retarding interior furnishings.

That points to oxygen generators, electrical systems that were unwillingly connected or shorted onto the battery, other gaseous systems or materials, or external factors (lightning strike, arson, etc...).

Image
boeing.com

RTM
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Re: Ethiopian Boeing 787 on fire at gate in London Heathrow

Post by RTM »

Flanker2 wrote:An aircraft isn't supposed to be connected to ground power while parked for 12 hours, unless there is someone watching it and doing something on or around it that requires electricity to be fed into the systems. But small independent batteries integrated into systems don't have enough power nor voltage to generate a powerful enough source of heat to ignite the fire-retarding interior furnishings.
Incorrect.

Ground handling busses can stay connected 24/7 without supervision. In fact, it is required to turn the cabin lighting on to full brightness several hours before departure just to charge the luminescent strips of the floor path emergency markings.

However, this doesn't switch on the aircraft, and most systems are unpowered.

I guess that if the investigators are focussing on the ELT, they will have a reason for that. If it is indeed a model of ELT that is widely used, it is a case of very bad luck. If it is a new design, than there is a problem. But no need to ground any airccraft. Just take them out, and install portable units for the time being...

bollox
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Re: Ethiopian Boeing 787 on fire at gate in London Heathrow

Post by bollox »

Did a bit of reading up.....Lithium Manganese batteries can be volatile under certain conditions, i.e above 100 deg C and especially when exposed to fire/flames. Dunno the construction of the ELT battery, but if heated by another source nearby (I assume it was in something like an electronics bay), it could catch fire (even explode) and easily torch through the crp structure.

Flanker2
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Re: Ethiopian Boeing 787 on fire at gate in London Heathrow

Post by Flanker2 »

Incorrect.

Ground handling busses can stay connected 24/7 without supervision. In fact, it is required to turn the cabin lighting on to full brightness several hours before departure just to charge the luminescent strips of the floor path emergency markings.
Ground handling busses will be powered indeed even if the master switch isn't on, but most of their systems are fed through circuit breakers and the customers are light appliances such as cabin lights, cargo lights, fueling panel and feed pumps. It's unlikely that they would cause a fire to start unless there is an issue in the design.
Cabin light ballasts can get pretty hot, but unless you have design or manufacturing issues, they are supposed to be protected by a control mechanism with C/B's.
However I have never seen cabin lights powered "several hours" prior to flight just to charge the stripes. Cabin lights are usually switched on when the crew arrives to start the preparations.
Did a bit of reading up.....Lithium Manganese batteries can be volatile under certain conditions, i.e above 100 deg C and especially when exposed to fire/flames. Dunno the construction of the ELT battery, but if heated by another source nearby (I assume it was in something like an electronics bay), it could catch fire (even explode) and easily torch through the crp structure.
Any lithium chemistry is not designed for operations above 50°c. But the ELT is still well protected thanks to its sturdy metal boxing. Even if the battery releases that heat, I'm not sure that it will be able to radiate enough heat to ignite the aircraft's structure. However if subjected to heat from a fire started elsewhere, it could self-combust and fuel the combustion process.

letscruise
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Re: Ethiopian Boeing 787 on fire at gate in London Heathrow

Post by letscruise »

A lot of speculations here, let's wait for the official NTBS report.

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Re: Ethiopian Boeing 787 on fire at gate in London Heathrow

Post by teddybAIR »

letscruise wrote:NTBS report.
:D Best writing error ever on luchtzak.be!

RTM
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Re: Ethiopian Boeing 787 on fire at gate in London Heathrow

Post by RTM »

Flanker2 wrote:
Ground handling busses will be powered indeed even if the master switch isn't on, but most of their systems are fed through circuit breakers and the customers are light appliances such as cabin lights, cargo lights, fueling panel and feed pumps. It's unlikely that they would cause a fire to start unless there is an issue in the design.
Cabin light ballasts can get pretty hot, but unless you have design or manufacturing issues, they are supposed to be protected by a control mechanism with C/B's.
However I have never seen cabin lights powered "several hours" prior to flight just to charge the stripes. Cabin lights are usually switched on when the crew arrives to start the preparations.
I seriously doubt the aircraft was fully powered-up, unless maintenance was in progress. So if it was powered-up in some form, it must have been the ground service busses.

As regard to the light strips... I do know it doesn't allways happen, but it should.

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sn26567
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Re: Ethiopian Boeing 787 on fire at gate in London Heathrow

Post by sn26567 »

The Wall Street Journal reveals in breaking news that AAIB will issue an interim report in a few days. It is unclear if ELT started the fire. It may suggest the removal of the ELT from 787s during probe.

On other news, it seems more and more likely that, to avoid any discontinuity in the carbon fibres structure, it will be necessary to replace the entire tail section. In such case, repairing the damaged airplane could take months or even one year. If Boeing opts to replace the entire tail section, that also could mean a long delay because there is no slack in the production line.
André
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Bralo20
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Re: Ethiopian Boeing 787 on fire at gate in London Heathrow

Post by Bralo20 »

teddybAIR wrote:
letscruise wrote:NTBS report.
:D Best writing error ever on luchtzak.be!
Double error even since the AAIB is in charge :)

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Re: Ethiopian Boeing 787 on fire at gate in London Heathrow

Post by KriVa »

RTM wrote:

In fact, it is required to turn the cabin lighting on to full brightness several hours before departure just to charge the luminescent strips of the floor path emergency markings.
I may be wrong, but I think you have your timings mixed up here.
According to our manual, the systems needs to charge during a period of 10-30 minutes(with the lights on full bright), and will keep glowing for several hours, not the other way around.
10-30 minutes is less than the time it takes to get the aircraft ready for a flight, so there is no reason at all to turn on the cabin lights several hours in advance.
Thomas

Flanker2
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Re: Ethiopian Boeing 787 on fire at gate in London Heathrow

Post by Flanker2 »

The question is, what if this occurred 8 hours later, while the 787 was flying over the Sahara desert enroute to ADD? If it was an ELT fire, no ELT, plus a most certain crash landing on the sand, if they had enough time to make it down there. Most helicopters don't have the range to do SAR in such a vast area, most Saharian countries don't have SAR or maritime patrol aircraft with the range to do SAR.

What if another aircraft with the same defect is in flight now and about to catch fire due to the same defect?

If it spontaneously catches fire and they can't pin-point the reason immediately, or it's a design/manufacturing problem, I think that the 787 is a safety hazard and should be grounded and inspected immediately.

A grounding is bad publicity, a crash will be the end of the 787 program.

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KriVa
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Re: Ethiopian Boeing 787 on fire at gate in London Heathrow

Post by KriVa »

Since ET-AOP has been on the ground for the last few days, I think the "grounding and inspectIng" part is taken care of. It's not like she's going somewhere anyway.
All we can do at this moment is speculate... And I might be wrong, but I can't seem to remember an incident or accident where the investigation was superfluous to the speculation that occurred.
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Re: Ethiopian Boeing 787 on fire at gate in London Heathrow

Post by Homo Aeroportus »

Flanker2 wrote:The question is, what if this occurred 8 hours later, while the 787 was flying over the Sahara desert enroute to ADD? ....
Don't know how you fold your map mate but LHR-ADD over the Sahara ??? :?

H.A.

RTM
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Re: Ethiopian Boeing 787 on fire at gate in London Heathrow

Post by RTM »

@flanker:
Don't you think that is the case with every incident/accident? What do you suggest, stop flying alltogether? Why treat the 787 any different to all other models? Let the investigators do their job, and if they think it is warrente, they will ground the fleet. But don't go waiting for it.

@KriVa
Let me check my source. I might be wrong as well. I'll come back on it.

Flanker2
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Re: Ethiopian Boeing 787 on fire at gate in London Heathrow

Post by Flanker2 »

KriVa wrote:Since ET-AOP has been on the ground for the last few days, I think the "grounding and inspectIng" part is taken care of. It's not like she's going somewhere anyway.
All we can do at this moment is speculate... And I might be wrong, but I can't seem to remember an incident or accident where the investigation was superfluous to the speculation that occurred.
I thought that ET-AOP would be taking off this afternoon? Sarcam - shock- language barrier - Bang -ding -ow :lol:

I mean to say that in my assessment, they should ground the 787, all of them, every single unit that's in operation, any B787 on the civil register with an airworthiness certificate, any aircraft certified under the B787 type certificate. I hope that it's clear enough now :lol:

Sometimes the language barrier on this forum is frustrating.

And now it seems that the lack of geographic knowledge poses a problem for some too...
Don't know how you fold your map mate but LHR-ADD over the Sahara ???
God help me.

Passenger
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Re: Ethiopian Boeing 787 on fire at gate in London Heathrow

Post by Passenger »

sn26567 wrote:The Wall Street Journal reveals in breaking news that AAIB will issue an interim report in a few days. It is unclear if ELT started the fire.
For those who say that they know the cause(s) already: let's wait for that interim report, shall we?

Flanker2
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Re: Ethiopian Boeing 787 on fire at gate in London Heathrow

Post by Flanker2 »

RTM wrote:@flanker:
Don't you think that is the case with every incident/accident? What do you suggest, stop flying alltogether? Why treat the 787 any different to all other models? Let the investigators do their job, and if they think it is warrente, they will ground the fleet. But don't go waiting for it.

@KriVa
Let me check my source. I might be wrong as well. I'll come back on it.
I think that a poster on pprune.org lays down the facts pretty well: post 383
There has been three fires in 787 fuselage to date with burn-through in two. This is in less than two years of flying and low flying hours, no risk analysis or fancy statistical stuff needed, 'Just the facts.Ma'am, just the facts" as Jack Webb said. Its obvious and clear that a major safety hazard exists on uninsulated (upper180 degrees including the cabin) and possibly on insulated fuselage (lower 180 degrees) and we don't need strawmen categories either.
Isn't it just an obvious, proven and clear safety hazard?
Regarding the strips, you are right about the first generation of strips, which took hours to charge enough light, but nowadays you don't need much time to make them glow long enough.

Flanker2
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Re: Ethiopian Boeing 787 on fire at gate in London Heathrow

Post by Flanker2 »

Passenger wrote:
sn26567 wrote:The Wall Street Journal reveals in breaking news that AAIB will issue an interim report in a few days. It is unclear if ELT started the fire.
For those who say that they know the cause(s) already: let's wait for that interim report, shall we?
We are allowed to speculate. This is a major accident, a 200 million brand new airframe just caught fire and 50+ others are still flying in revenue service carrying passengers. I think that it's pretty controversial.

This is different from Egyptair's B772, in that the B787 is in revenue service since a very short period of time and that the aircraft was not energised. It was just parked. Since it has not been in heavy maintenance yet, it's also unlikely that new errors were added during this process. The airframe was brand new.

The B787 has seen 4 fire events so far, including one during flight testing.
Will you put your children on a B787 today? Or you don't care as long as it's someone else's life?

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