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UK Investigators: Disable Locator Beacon on 787s
U.K. air accident investigators recommended Thursday that aviation authorities temporarily disable a Honeywell emergency transmitter on all Boeing 787 Dreamliners following a fire last week at London's Heathrow Airport. A spokeswoman for the investigation branch said the easiest way to make the transmitter systems "inert" — as set out in their recommendations — would be to take out their batteries. (abcnews.go.com) More...
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Hmmmm...taking emergency transmitters out of aircraft that seem to be catching on fire a lot...penny wise?
According the the AAIB report there are approximately 6,000 similar beacons in use across the world. These are not just limited to the 787.
Investigators have yet to reach firm conclusions over the source of the fire. But the area of greatest heat damage, in the rear fuselage crown, "coincides" with the ELT's internal mounting location and associated wiring, says the Air Accidents Investigation Branch.
Although the 787 was plugged into a ground power source, with umbilical cables, the stand's power had been switched off - a status visually confirmed by an engineer in the cockpit before he vacated the jet.
"There are no other aircraft systems in this vicinity [of the ELT] which, with the aircraft unpowered, contain stored energy capable of initiating a fire in the area of heat damage," says the inquiry.
Firefighters summoned to the 787 sprayed the aircraft with water and foam, and unplugged the umbilical cables as a precaution. They entered through a forward left-hand passenger door, encountering thick smoke, and saw signs of fire above rear ceiling panels in the cabin.
Attempts to tackle it with a handheld halon extinguisher were unsuccessful, so a ceiling panel was moved and the fire was put out with water hoses.
"Had this event occurred in flight it could pose a significant safety concern and raise challenges for the cabin crew in tackling the resulting fire," says the AAIB.
Honeywell's Rescu406AFN transmitter, which contains lithium-manganese dioxide batteries, has become the focus of the probe.
The company has manufactured around 6,000 units of the same design but the AAIB points out that the incident appears "extremely rare", with the 787 fire the "only significant thermal event" involving the 406MHz device.
Examination of the ELT indicates a degree of "disruption" to the battery cells, but it adds: "It is not clear, however, whether the combustion in the area of the ELT was initiated by a release of energy within the batteries or by an external mechanism such as an electrical short.
"In the case of an electrical short, the same batteries could provide the energy for an ignition and suffer damage in the subsequent fire."
The 787 sustained extensive heat damage in the upper part of its rear fuselage and significant thermal effects on the insulation and composite aircraft structure.
Although the 787 was plugged into a ground power source, with umbilical cables, the stand's power had been switched off - a status visually confirmed by an engineer in the cockpit before he vacated the jet.
"There are no other aircraft systems in this vicinity [of the ELT] which, with the aircraft unpowered, contain stored energy capable of initiating a fire in the area of heat damage," says the inquiry.
Firefighters summoned to the 787 sprayed the aircraft with water and foam, and unplugged the umbilical cables as a precaution. They entered through a forward left-hand passenger door, encountering thick smoke, and saw signs of fire above rear ceiling panels in the cabin.
Attempts to tackle it with a handheld halon extinguisher were unsuccessful, so a ceiling panel was moved and the fire was put out with water hoses.
"Had this event occurred in flight it could pose a significant safety concern and raise challenges for the cabin crew in tackling the resulting fire," says the AAIB.
Honeywell's Rescu406AFN transmitter, which contains lithium-manganese dioxide batteries, has become the focus of the probe.
The company has manufactured around 6,000 units of the same design but the AAIB points out that the incident appears "extremely rare", with the 787 fire the "only significant thermal event" involving the 406MHz device.
Examination of the ELT indicates a degree of "disruption" to the battery cells, but it adds: "It is not clear, however, whether the combustion in the area of the ELT was initiated by a release of energy within the batteries or by an external mechanism such as an electrical short.
"In the case of an electrical short, the same batteries could provide the energy for an ignition and suffer damage in the subsequent fire."
The 787 sustained extensive heat damage in the upper part of its rear fuselage and significant thermal effects on the insulation and composite aircraft structure.
do they reccommend zlso that the 787s only catch fire on the ground, at the gate, where they can easially be located?
Let's see... the fire is blamed on the ELT unit supplied by a third party. Yet the recommendation is to allow over 5900 of these ELT units to continue in service on other types of airplanes but to "make inert" only those installed on 787's. That makes perfect sense ! :0
Fires on the 787 are becoming as big a problem as cargo door fails did on the DC10, fortunately without the loss of life. The DC10 went on to become a highly reliable plane, and I'm sure the 787 will as well, Boeing just needs to do some serious damage control. This is coming from an Airbus fan, but the 787 is a beautiful bird.
