A fire on a Boeing 787 Dreamliner at Heathrow in 2013 was caused by trapped battery wires, British aviation investigators have revealed. The civilian aircraft, operated by Ethiopian Airlines, caught fire while on a remote parking stand at London Heathrow in July 2013, reported Independent. No one was on board the plane at the time of firing, but the aircraft had sustained serious damage in the fire.

The U.K.'s Air Accident Investigations Branch (AAIB), in its report on Wednesday, said a short circuit appeared to have caused the lithium battery to ignite.

"The only source of stored energy within the fire-affected area of the crown was the ELT and the severity of the damage to the ELT and its mounting structure confirmed that it was the source of the fire," the report said.

The report said ELT battery wires, crossed and became trapped under the battery cover and probably created a short-circuit resulting in a rapid and uncontrolled discharge of the battery.

"In the event of an in-flight ELT battery fire, fighting the ELT fire and any subsequent structural fire would be challenging for cabin crew due to the inaccessible location of the ELT in the cabin," AAIB noted in its report, according to Mirror.

The AAIB makes a number of safety recommendations, including that the Federal Aviation Administration (FAA)) should assess the beacon and its battery to avoid future incidents, according to Sky News.

"Had this event occurred on an occupied aircraft the fire would not have been visible to either passengers or crew. Nor would any heat effect from the fire have been apparent to the occupants," the report said, according to Bloomberg.