The Federal Aviation Administration has ordered airlines operating Boeing's 787 "Dreamliner" to conduct a safety check on the aircraft's emergency locator transmitter. The order comes after British aviation authorities narrowed the source of the recent fire aboard an Ethiopian Airlines 787 at Heathrow to the transmitter and urged the FAA to tell airlines to disconnect the batteries from the beacons on all aircraft.

The emergency locator transmitter, which broadcasts an automated signal in the event of a crash, is located near the tail of the plane, in an area where there are no fire suppression systems. If an electrical fire were sparked by the transmitter in flight, British officials said that "it could pose a significant safety concern and raise challenges for the cabin crew.”

Reuters reports that Japanese aviation officials have issued a temporary safety order approving the removal of 787 emergency transmitter batteries, allowing aircraft to fly without the beacon enabled.The FAA's order doesn't go as far as that, ordering only that a safety check be performed on the wiring of the transmitter.

The order is not nearly as severe as the one that grounded the 787 after the January battery fire aboard a JAL 787 at Boston's Logan Airport, but the apparent wiring problem is more bad news for Boeing's Dreamliner, a plane whose manufacturing process has been largely outsourced to subcontractors.