A Boeing plan to redesign the 787 Dreamliner’s fire-plagued lithium-ion batteries won approval from the US Federal Aviation Administration (FAA), although officials gave no estimate for when the planes would be allowed to fly passengers again.
The 787 fleet worldwide has been grounded by the FAA and civil aviation authorities in other countries since Jan. 16, following a battery fire on a Dreamliner parked in Boston and a smoking battery that led to the emergency landing of other 787 planes in Japan.
The 787 is Boeing’s newest and most technologically advanced plane. Its grounding marked the first time since 1979 that the FAA had ordered every plane of a particular type to stay out of the air for safety reasons.
The Boeing plan includes changes to the internal battery components to minimize the possibility of short-circuiting, which can lead to overheating and cause a fire. Among the changes are better insulation of the battery’s eight cells and the addition of a new containment and venting system, the FAA said in a statement on Tuesday.
US Representative Rick Larsen, who was briefed by the agency, said that if all goes well, the FAA could give final approval by middle of or late next month for the 787 to resume flight.
Boeing would still have to retrofit the 50 planes already delivered to eight airlines in seven countries, Larsen said in an interview.
That could mean the plane would not return to the skies until late next month or early May, Larsen said.
First, Boeing’s redesigned batteries have to pass 20 separate lab tests, Larsen said, then flight tests would follow.
“If there’s any one test that isn’t passed, it’s back to the drawing board for that particular part of the tests,” he said.
So far, test flights of two 787s have been approved — one with a complete prototype of the new battery, the other with only a new, more robust containment box for the battery, Boeing spokesman Marc Birtel said.
The plan is an outline for a recertification of the plane’s batteries, the FAA said. The 787 has two identical lithium-ion batteries, one of which is located toward the front of the plane and powers cockpit electrical systems, the other toward the rear and used to start an auxiliary power unit while the plane is on the ground, among other functions.
Every item that is part of an airplane, down to its nuts and bolts, must be certified as safe before the FAA approves that type of plane as safe for flight.
“This comprehensive series of tests will show us whether the proposed battery improvements will work as designed,” US Transportation Secretary Ray LaHood said in a statement. “We won’t allow the plane to return to service unless we’re satisfied that the new design ensures the safety of the aircraft and its passengers.”
All Nippon Airways, the largest customer for the plane so far, said in a statement from Japan that it saw the FAA decision as significant progress.
“Putting safety as the first priority, we hope to get the planes back in the air as soon as possible,” the airline said.
Boeing plans to begin test flights within days, Birtel said.
The FAA’s approval of Boeing’s battery plan “is a critical and welcome milestone toward getting the fleet flying again and continuing to deliver on the promise of the 787,” Boeing CEO Jim McNerney said in a statement.