British authorities blame transmitter in Boeing 787 Dreamliner fire

British accident investigators determined that an emergency device was probably responsible for the fire that broke out last week on an empty Boeing Co. 787 Dreamliner parked at London’s Heathrow Airport and advised airlines to disable it on all planes.

In addition, Britain’s Air Accidents Investigation Branch issued a “special bulletin” Thursday urging U.S. regulators to conduct an extensive safety review.

The Federal Aviation Administration will now have to decide what to do about the device, which is installed on the worldwide problem-plagued 787 fleet and thousands of other commercial airplanes.

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The British accident investigation team’s initial three-page report outlines what happened on the Ethiopian Airlines plane and its emergency locator transmitter, which emits signals to emergency crews in crisis situations.


The transmitter model, made by Honeywell International Inc., is installed on the top of the 787 near the tail of the plane, where the fire burned Friday. The 787 contains a set of chemical batteries using lithium-manganese dioxide.

“Indications of disruption to the battery cells,” the report said. “It is not clear, however, whether the combustion in the area of the ELT was initiated by a release of energy within the batteries or by an external mechanism such as an electrical short.”

Honeywell said the transmitter has been certified by the FAA since 2005, and added that temporarily disabling the devices “as a precautionary measure is prudent.”

“The investigation continues, and it’s premature to jump to conclusions,” the company said in a statement. The 787 “product action is a straightforward process.”

Honeywell said it will support conducting safety reviews for installations of any of its lithium battery-powered devices from the manufacturers who sell them.

The report said that the 787 landed after an uneventful flight from Ethiopia. It was towed to an remote parking stand to await its next service later that day. Ten hours later, an employee in the air traffic control tower noticed smoke billowing from the plane.

The airport fire service arrived, spraying water and foam. Firefighters then entered the smoke-filled plane and saw fire at the rear of the cabin.

First, they tried killing the fire with a handheld extinguisher but it didn’t work. So, they removed a ceiling panel and put it out with hoses.

“Surveying and detailed examinations of damaged areas revealed that the greatest heat damage and highest temperatures were centered on the rear fuselage close to the crown and displaced to the left of the aircraft center line,” the report said. “This corresponds to the most damaged external areas, with blackened and peeling paint and damage to the composite structure. It also coincides with the location of the aircraft’s emergency locator transmitter and its associated system wiring.”

Boeing has had battery problems with the 787 fleet before.

Lithium-cobalt batteries were at fault in January when federal regulators banned all 787 planes from flying after batteries on two planes overheated, with one catching fire.

Boeing later ordered modifications to the jets to increase ventilation and insulation near the batteries, but the company and investigators never determined the root cause of the overheating. The jets were allowed to fly four months later.

They were not found to be at fault in Friday’s fire.

Boeing said in a statement that it supports the two recommendations from the accident investigation team, “which we think are reasonable precautionary measures to take as the investigation proceeds.”

Wall Street responded positively to Thursday’s news. At one point, Boeing shares rose $2.24, or 2.1%, to $107.03.


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