Ethiopean 787 fire at Heathrow
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Fire/incendiary investigations often can be the toughest to crack specially if one looks for a 'root cause'. Six days is absolutely nothing.
But if it sits in one piece on the ramp with localized fire damage and fully accessible, I would expect a more informative press release by now.
Then why do we have so many posters suggesting that it's unrepairable ?
I wonder where the coffee pot problem came from then?
certainly by now if it were localized PPrune posters would have already solved it.
Boeing 787 Probe Spurs Honeywell Beacon Shutdown, Lithium Checks
By Robert Wall
July 18 (Bloomberg) -- U.K. authorities probing last week’s fire on a Boeing Co. 787 at Heathrow airport said a Honeywell International Inc. beacon installed close to the site of the blaze should be deactivated on all other Dreamliners.
Britain’s Air Accidents Investigation Branch said in a special bulletin that the U.S. Federal Aviation Administration should also lead a safety review into lithium battery-powered transmitters on other aircraft models.
Shutting off the Emergency Locator Transmitter system on the Boeing jet is a precautionary measure “until appropriate airworthiness actions can be completed,” the AAIB said.
The July 12 incident on a Ethiopian Airlines Enterprise Dreamliner was the most-serious setback for Boeing’s marquee jet since regulators ordered the global 787 fleet idled for three months following fires linked to lithium-ion batteries. The AAIB hasn’t called for a grounding following the Heathrow event.
“Had this event occurred in flight it could pose a significant concern and raise challenges for the cabin crew in tackling the resulting fire,” the AAIB said today. “The ELT has shown some indications of disruption to the battery cell.”
Overheating of emergency transmitters “is extremely rare” and last week’s incident was the first affecting the Honeywell system, the safety body said.
Smoke Spotted
The AAIB probe, which included Boeing, the airline, and U.S. safety representatives, was broadened to include Honeywell after the beacon made by the Morris Township, New Jersey-based company was isolated as a potential cause of the fire.
The ELTs rely on chemical batteries made of lithium-manganese dioxide to power the beacon even if the plane’s electrical system fails.
Air traffic control personnel spotted smoke coming from the Ethiopian jet, parked and not under power, at 4:34 p.m. local time, with emergency personnel arriving a minute later to extinguish the fire, according to today’s bulletin.
Fire fighters using breathing equipment entered the plane and initially failed to suppress the blaze using Halon devices. They then removed ceiling panels and applied water.
The plane suffered “extensive heat damage” in the rear, including to its composite-plastic fuselage, the AAIB said. The ELT is the only aircraft system in the area, it said. Flight crew had not reported any technical problems with the plane.
Other Dreamliner users from ANA Holdings Inc., the first to operate the jet, to United Airlines, the world’s largest carrier, have maintained 787 services. Ethiopian Airlines has also continued to operate its three other planes.
Boeing had delivered 66 Dreamliners to 11 airlines and a leasing company through June. The Chicago-based planemaker has booked 930 firm orders for the jet, which has a list price of $206.8 million in its cheapest version.
By Robert Wall
July 18 (Bloomberg) -- U.K. authorities probing last week’s fire on a Boeing Co. 787 at Heathrow airport said a Honeywell International Inc. beacon installed close to the site of the blaze should be deactivated on all other Dreamliners.
Britain’s Air Accidents Investigation Branch said in a special bulletin that the U.S. Federal Aviation Administration should also lead a safety review into lithium battery-powered transmitters on other aircraft models.
Shutting off the Emergency Locator Transmitter system on the Boeing jet is a precautionary measure “until appropriate airworthiness actions can be completed,” the AAIB said.
The July 12 incident on a Ethiopian Airlines Enterprise Dreamliner was the most-serious setback for Boeing’s marquee jet since regulators ordered the global 787 fleet idled for three months following fires linked to lithium-ion batteries. The AAIB hasn’t called for a grounding following the Heathrow event.
“Had this event occurred in flight it could pose a significant concern and raise challenges for the cabin crew in tackling the resulting fire,” the AAIB said today. “The ELT has shown some indications of disruption to the battery cell.”
Overheating of emergency transmitters “is extremely rare” and last week’s incident was the first affecting the Honeywell system, the safety body said.
Smoke Spotted
The AAIB probe, which included Boeing, the airline, and U.S. safety representatives, was broadened to include Honeywell after the beacon made by the Morris Township, New Jersey-based company was isolated as a potential cause of the fire.
The ELTs rely on chemical batteries made of lithium-manganese dioxide to power the beacon even if the plane’s electrical system fails.
Air traffic control personnel spotted smoke coming from the Ethiopian jet, parked and not under power, at 4:34 p.m. local time, with emergency personnel arriving a minute later to extinguish the fire, according to today’s bulletin.
Fire fighters using breathing equipment entered the plane and initially failed to suppress the blaze using Halon devices. They then removed ceiling panels and applied water.
The plane suffered “extensive heat damage” in the rear, including to its composite-plastic fuselage, the AAIB said. The ELT is the only aircraft system in the area, it said. Flight crew had not reported any technical problems with the plane.
Other Dreamliner users from ANA Holdings Inc., the first to operate the jet, to United Airlines, the world’s largest carrier, have maintained 787 services. Ethiopian Airlines has also continued to operate its three other planes.
Boeing had delivered 66 Dreamliners to 11 airlines and a leasing company through June. The Chicago-based planemaker has booked 930 firm orders for the jet, which has a list price of $206.8 million in its cheapest version.
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AAIB bulletin has now been released.
Air Accidents Investigation: S5/2013 - Boeing 787, ET-AOP
"A fire event occurred on a parked, unoccupied and electrically un-powered Boeing 787 aircraft at London Heathrow Airport. Subsequent examination of the fire-affected area has focussed on the Emergency Locator Transmitter (ELT). Two Safety Recommendations have been made."
Air Accidents Investigation: S5/2013 - Boeing 787, ET-AOP
"A fire event occurred on a parked, unoccupied and electrically un-powered Boeing 787 aircraft at London Heathrow Airport. Subsequent examination of the fire-affected area has focussed on the Emergency Locator Transmitter (ELT). Two Safety Recommendations have been made."
The alarming thing for me , and it is stated on the final page of the AAIB's reort is that if the ELT battery is at fault there remains the possibility that this failure could have occurred in flight in a fuselage zone with restricted access and no local fire surpression or detection.
Last edited by tubby linton; 18th Jul 2013 at 15:19. Reason: speeling
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Interesting bit from the report (often what is chosen to include in a preliminary report can be revealing):
Given prior "sneak paths" in the electrical system one wonders if having the cable connected but unpowered resulted in an unforseen circuit.
I have no idea exactly what turning off the power at the stand does, all conductors disconnected, all grounded or some other configuration.
Does sound liket the ELT is involved though, of course there is still the chicken and egg question. (Which came first)
Think about that long enough and you end up with a chicken ommellete...
The ground handling agent accordingly turned
off ground power at the stand’s control box but left the
power umbilical cables attached. The engineer visually
confirmed on the flight deck that ground power was no
longer available.
off ground power at the stand’s control box but left the
power umbilical cables attached. The engineer visually
confirmed on the flight deck that ground power was no
longer available.
I have no idea exactly what turning off the power at the stand does, all conductors disconnected, all grounded or some other configuration.
Does sound liket the ELT is involved though, of course there is still the chicken and egg question. (Which came first)
Think about that long enough and you end up with a chicken ommellete...
Last edited by MurphyWasRight; 18th Jul 2013 at 15:29. Reason: Spelling and clarity
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In view of LeadSled's earlier post about Australian findings on ELTs, the permanent removal of fixed ELTs would appear to be the most appropriate action.
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The report also says there over 6000 of this version of ELT's out there fitted to a variety of aircraft, with this being the only significant thermal event.
Is this just a case of bad luck of a faulty unit being fitted to a 787?
Is this just a case of bad luck of a faulty unit being fitted to a 787?
What is the service history of the Honeywell unit? Any other experience with these things bursting into flames?
On a related note: What sort of connections does the ELT have with the aircraft power system? There is a flight deck test switch plus activation annunciation. Is this powered from the aircraft DC system? Any chance that it was connected to a 32 Vdc buss (most other applications are likely to be 28 Vdc).
On a related note: What sort of connections does the ELT have with the aircraft power system? There is a flight deck test switch plus activation annunciation. Is this powered from the aircraft DC system? Any chance that it was connected to a 32 Vdc buss (most other applications are likely to be 28 Vdc).
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Another case where -- assuming that the initial findings are correct - it's not clear whether the underlying fault was in the battery or the circuitry to which it was connected. Is anyone familiar enough with the ELT circuit to know whether the battery is fused?
High energy battery circuits are supposed to have some form of thermal or electrical cut-out that trips before enough energy has been delivered to start a fire. So, once again, there are two failures to explain: whatever it was that caused the bake-off, and whatever it was that was supposed to stop that happening but didn't.
Interesting that the recommendation to remove the ELT was restricted to 787 carriers. If this is a common part across types, is this an indication that the 787 is uniquely vulnerable?
High energy battery circuits are supposed to have some form of thermal or electrical cut-out that trips before enough energy has been delivered to start a fire. So, once again, there are two failures to explain: whatever it was that caused the bake-off, and whatever it was that was supposed to stop that happening but didn't.
Interesting that the recommendation to remove the ELT was restricted to 787 carriers. If this is a common part across types, is this an indication that the 787 is uniquely vulnerable?
What is the service history of the Honeywell unit? Any other experience with these things bursting into flames?
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From the BBC "The AAIB said the problem might not be confined to the 787 and recommended that regulators conduct a safety review of similar components in other aircraft."
Does anyone know if there a reason they would have to say that (rather that "turn them all off now") for types other than the one they are investigating? I can't think of one unless they suspect some 'unfortunate' interaction between an ELT battery issue and the 787 systems that wouldn't affect other aircraft types?
Does anyone know if there a reason they would have to say that (rather that "turn them all off now") for types other than the one they are investigating? I can't think of one unless they suspect some 'unfortunate' interaction between an ELT battery issue and the 787 systems that wouldn't affect other aircraft types?
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Does anyone know if there a reason they would have to say that (rather that "turn them all off now") for types other than the one they are investigating? I can't think of one unless they suspect some 'unfortunate' interaction between an ELT battery issue and the 787 systems that wouldn't affect other aircraft types?
For others types it is an open question if the same scale event would have breached the hull. Still not something that one would want in flight though.
Also on protection of battery by fuse, from the spec sheet the unit is rated at 5W at 406Mhz, plus lesser at the lower frequencies.
This translates to expected power in use in the 8 to 12 watt range, plenty to get a wire hot enough to cause trouble.
Could be higher, 8 watts would actually be very impressive effeciency figure.
Last edited by MurphyWasRight; 18th Jul 2013 at 16:36. Reason: Spelling and added comment on battery protection
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Only way to make the ELT inert is to pull the battery pack out.
Artex uses ship power for the light in the cockpit, not sure about Honeywell.
There should be no direct, or even indirect, path between the ship power and the ELT battery pack.
Looking at an Artex pack, I can see a potential failure mode that would short a cell out. I have no reason to think Honeywell's execution of a battery pack would be much different.
If I'm thinking what the AAIB is thinking, were all gonna be pulling ELT's out of everything.
ETA: Self Loading Freight. on the Artex battery pack, it goes straight two 2 fuses in the pack itself.
Artex uses ship power for the light in the cockpit, not sure about Honeywell.
There should be no direct, or even indirect, path between the ship power and the ELT battery pack.
Looking at an Artex pack, I can see a potential failure mode that would short a cell out. I have no reason to think Honeywell's execution of a battery pack would be much different.
If I'm thinking what the AAIB is thinking, were all gonna be pulling ELT's out of everything.
ETA: Self Loading Freight. on the Artex battery pack, it goes straight two 2 fuses in the pack itself.
Last edited by LASJayhawk; 18th Jul 2013 at 16:41.
Maybe the Aussies have it right, and the requirements were not well substantiated in the first place, particularly for long haul airliners who tend to fly under radar control or under well established flight routes.
The GA event presented as the trigger hardly fits the "we know where it is or will be" model of an airline flight. I can see how an ELT is a good idea when you fly in out of the way areas, or typically in uncontrolled airspace.
I'd be interested to hear what people in the SAR community, civil and military, think about ELT's as an aid to their making first contact with a downed aircraft.
The GA event presented as the trigger hardly fits the "we know where it is or will be" model of an airline flight. I can see how an ELT is a good idea when you fly in out of the way areas, or typically in uncontrolled airspace.
I'd be interested to hear what people in the SAR community, civil and military, think about ELT's as an aid to their making first contact with a downed aircraft.
Last edited by Lonewolf_50; 18th Jul 2013 at 16:38.
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Power-wise, this unit is completely self-contained, self-testing and with a ten year battery life.
The only electrical integration with the aircraft's systems would seem to be this connection to a flight deck 'test switch'.
Are all Honeywell ELTs connected to the flight deck or just those fitted to the 787?
I am struggling to see how a low voltage/data connection can cause a fire, even when incorrectly connected. And the unit itself in a quiescent state is unlikely to draw more than a few milliamps from the onboard battery, not unlike an electric clock battery which can tick for several years on a single AA 1.5 volt cell.
I can only imagine that if the beacon is the cause of the fire, it somehow suffered some mechanical damage either inflight or during manufacture and installation.
The only electrical integration with the aircraft's systems would seem to be this connection to a flight deck 'test switch'.
Are all Honeywell ELTs connected to the flight deck or just those fitted to the 787?
I am struggling to see how a low voltage/data connection can cause a fire, even when incorrectly connected. And the unit itself in a quiescent state is unlikely to draw more than a few milliamps from the onboard battery, not unlike an electric clock battery which can tick for several years on a single AA 1.5 volt cell.
I can only imagine that if the beacon is the cause of the fire, it somehow suffered some mechanical damage either inflight or during manufacture and installation.
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The requirement for a remote switch in the cockpit on all new installations has been around in the US for 10+ years. All aircraft all installations.
Last edited by LASJayhawk; 18th Jul 2013 at 16:53.