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Emergency Locator Transmitter (ELT) eyed as a source of Boeing 787 ground fire
21 July 2013

The Air Accidents Investigation Branch (AAIB) reported that it was examining the Emergency Locator Transmitter (ELT) as a possible source of the fire that damaged a Boeing 787 Dreamliner at London-Heathrow Airport.

On July 12, 2013, a fire occurred on a parked, unoccupied and electrically un-powered Boeing 787-8 Dreamliner of Ethiopian Airlines.  An employee in the air traffic control tower had noticed smoke emanating from the aircraft and activated the crash alarm.

Firefighters entered the aircraft at the L2 door and encountered thick smoke. As they moved to the rear of the aircraft the smoke became denser so they opened further cabin doors to clear the smoke. At the rear of the passenger cabin they observed indications of fire above the ceiling panels. They attempted to tackle the fire with a handheld “Halon” extinguisher but this was not effective, so they forcibly moved a ceiling panel and tackled the fire with water from hoses. This was effective and the fire was extinguished.
The greatest heat damage and highest temperatures were centered on the rear fuselage close to the crown and displaced to the left of the aircraft center line. This correlates to the most damaged external areas, with blackened and peeling paint and damage to the composite structure. It also coincides with the location of the aircraft’s Emergency Locator Transmitter (ELT) and its associated wiring system. The ELT stores it’s own energy in Lithium-Manganese Dioxide (LiMnO2) batteries.

The AAIB issued two safety recommendions:

  • It is recommended that the Federal Aviation Administration initiate action far making inert the Honeywell International RESCU406AFN fixed Emergency Locator Transmitter system in Boeing 787 aircraft until appropriate airworthiness actions can be completed.
  • It is recommended that the Federal Aviation Administration, in association with other regulatory authorities, conduct a safety review of installations of Lithium-powered Emergency Locator Transmitter systems in other aircraft types and, where appropriate, initiate airworthiness action.

The Federal Aviation Administration is working with Boeing to develop instructions to operators for inspection of the ELT wiring, while ATW reported that EASA was working on an airworthiness directive (AD) to instruct European operators to remove the ELT. Current European operators of the Dreamliner are: British Airways, LOT Polish Airlines and Thomson Airways.

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