Air accident investigators in London said Saturday that a fire inside a parked Boeing 787 Dreamliner on Friday did not appear to be caused by any problems with the plane’s new lithium-ion batteries.
The British Air Accidents Investigation Branch said in a statement that the fire resulted in smoke throughout the plane and extensive heat damage in the upper part of the rear fuselage. But while the investigators have not found the cause of the problems, the damage was not near either of the plane’s lithium-ion batteries. “At this stage,” the statement said, “there is no evidence of a direct causal relationship” between the batteries and the fire.”
That initial finding was a big relief to Boeing, its investors and the 13 airlines that have bought the planes, which were grounded for four months earlier this year after two episodes involving fire or smoke from the batteries. But the eventual findings about the cause of the latest fire, which occurred on an Ethiopian Airlines 787 parked at Heathrow Airport on Friday, could still mark a setback for Boeing if the investigators find problems with another crucial system on the plane.
The investigation branch said its initial inquiry would most likely take several days, and it did not offer any other comment on possible causes. Other safety experts said the possibilities could include heated elements left on in a galley just below where the fire burned thorough the jet’s carbon-composite skins, a poorly installed part or a short in the plane’s electrical system.
The innovative planes were grounded worldwide in mid-January after the incidents involving fire or smoke coming from the new and more volatile types of batteries. But the first 50 planes began flying again between late April to early June after regulators approved a series of fixes, including adding insulation between the battery cells and encasing the batteries inside a steel box.
Ethiopian Airlines said in a statement earlier Saturday that it was continuing to fly its other 787s because the fire at Heathrow occurred after the jet had been on the ground for eight hours and “was not related to flight safety.” The airline did not comment on the possible cause of the fire.
The other airlines with the planes, including United Airlines and 10 other foreign carriers, have also continued to fly them while the incident at Heathrow is under investigation.
The fire at Heathrow caused no injuries or significant damage but did disrupt travel in Britain and elsewhere. Investors reacted nervously, sending Boeing’s shares down 4.7 percent on Friday.
Smoke came from the plane, named the Queen of Sheba, eight hours after it had been parked in a remote space at Heathrow and about 4 1/2 hours before it was scheduled to depart for Ethiopia. No passengers were on the plane, which was connected to an external ground power source, according to people briefed on the episode.
It was also not clear if any maintenance was underway or how long the fire had been burning, though it was intense enough to burn through its carbon-composite skin on the top of the fuselage near the tail.
That area was in a complex section of the plane’s fuselage when large parts of the plane are joined together. The two lithium-ion batteries, which were used instead of conventional nickel-cadmium batteries to save weight and provide more energy, are located under the cockpit and just behind the wings toward the bottom of the plane.
In addition to the British investigators leading the inquiry, a team from Boeing was on site along with representatives from the airline and from two U.S. government agencies, the Federal Aviation Administration and the National Transportation Safety Board.
Boeing, the FAA and the NTSB had no comment Saturday on the possible cause of the fire.