Emergency beacon indentified as cause of fire on Dreamliner

Airlines could be ordered to check thousands of emergency beacons following an investigation into a fire on a Boeing 787 Dreamliner at London's Heathrow airport last week.

Britain's Air Accidents Investigation Branch has found the cause of a fire on board the Ethiopian Airways plane that led to both of Heathrow's runways being shut for 90 minutes.

An investigation found the fire started near the aircraft's emergency locator transmitter - a device used to help rescuers find a plane.

The device, made by Honeywell, is powered by a lithium manganese battery, which could have suffered a short circuit.

The investigation branch has urged the US Federal Aviation Administration to instruct Boeing to switch off the beacons on its Dreamliner fleet until they are found to be airworthy.

However, this would not lead to a grounding of the 68 Dreamliners in service, the Department for Transport said.

Earlier this year, 50 Dreamliners were grounded on the instructions of the aviation agency following a series of fires, which raised concern about the lithium ion batteries in the aircraft's main power system.

The agency was also advised to order a safety review of other lithium-powered beacons, which are found on a number of aircraft apart from the Dreamliner.

According to the investigation report, there are about 6000 similar beacons in use across the world.

The agency said: "Safety is our top priority. The FAA has been an active participant in the investigation into the incident involving a Boeing 787 while parked on the ground in London."

A Boeing spokesman said it accepted the recommendations from the investigation board.

"We are confident the 787 is safe and we stand behind its overall integrity," a spokesman said.

Honeywell said it backed the move to switch off the part but it was "premature to jump to conclusions".

Boeing shares fell 2 per cent in after-hours trading on Thursday after a Japan Airlines Dreamliner flying from the US to Tokyo was forced back for "maintenance".