Aviation regulators will allow Boeing 787 Dreamliners to operate in Japan without locator beacons which have been identified by British investigators as a likely source of a fire on board one of the aircraft in London last week, two aviation sources said.

ANA Holdings, which has 20 Dreamliners, and Japan Airlines, which has eight, need fly only with their portable emergency transmitters, said the sources, who had knowledge of the rule change.

Britain's Air Accident Investigation Branch (AAIB) said the locator beacon made by Honeywell International and its lithium-based battery was the only equipment on the Ethiopian Airlines plane parked at Heathrow Airport that had the power to start a fire and called on regulators to review its use.

ANA, the world's biggest operator of Boeing's carbon composite plane, will over the next two weeks remove all the emergency beacons from its 787s to inspect them and their batteries for any defects or damage, a company spokesman said. - Reuters