United Airlines, the only U.S. airline flying the Dreamliner, must complete the inspections of the emergency locator transmitter on its six planes by Aug. 5, the Federal Aviation Administration said today in its rule. It will be published in the Federal Register tomorrow.
"The investigation indicates that the ELT may have initiated the event," the FAA said in the order. "Discrepancies within the ELT, if not corrected, could cause a fire in the aft crown of the airplane."
The blaze that broke out on an Ethiopian Airlines Enterprise 787 parked at London's Heathrow Airport was traced to a Honeywell International Inc. transmitter powered by a lithium battery. The FAA, in its order, said it will look at safety of such devices on other aircraft.
Boeing 787 operators in Europe are due to be told tomorrow what to do with the beacon, after U.K. aviation-safety officials called for the device to be disabled -- a step beyond what the FAA is recommending.
The Cologne-based European Aviation Safety Agency said it is still working on details of the instructions, according to an e-mailed response to questions. The order will apply to all European 787 operators.
Rules vary around the world on whether commercial aircraft must have emergency beacons to operate. While they aren't mandated on airliners operating in the U.S., other nations require them, according to the FAA.
EASA may provide additional instructions on whether planes could operate temporarily without the beacons when it issues its version of the directive, it said.
The FAA had said July 19 it intended to issue its order.
Investigators are examining whether two wires smashed under a cover on the ELT may have short-circuited, triggering the fire in the ceiling of the 787 that was parked at Heathrow airport and had no one aboard, a person familiar with the probe said. The ELT contained a lithium-manganese-dioxide nonrechargeable battery that became involved in the fire, according to the U.K. Air Accidents Investigation Branch.
The FAA's action is an interim step, according to the order. There have been about 6,000 of the Honeywell beacons installed on aircraft, according to the AAIB.
"We acknowledge that ELTs are installed on various other aircraft," the FAA said in the order. "Therefore, continued investigation is required. Once final action has been identified, we might consider further rulemaking."
The FAA order requires airlines to inspect the device or remove it. The agency estimated it would take a mechanic one hour per plane to follow the directive, at a cost of $85 per hour.
The order didn't say what mechanics should look for in the inspection. The FAA said in its earlier statement they should examine the device for pinched wires, signs of excessive heat and moisture.
"We will comply with the airworthiness directive, and we do not expect any operational impact," Christen David, a spokeswoman for Chicago-based United, said in an interview.
Thomson Airways, the only U.K. carrier operating the jet, removed the Honeywell locators while Poland's LOT, the first European airline to receive the jet, said it has made checks and the part is "fine." Norwegian Air Shuttle AS also operates Dreamliners on lease from International Lease Finance Corp.