WASHINGTON—A Boeing plan to redesign the 787 Dreamliner’s fire-plagued lithium-ion batteries has won approval from the Federal Aviation Administration, moving the cutting-edge planes a step closer to flying passengers again.
The 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.
The FAA statement didn’t provide an estimate for when the grounded planes might return to service.
Rep. Rick Larsen, D-Wash., who was briefed by the agency, said that if all goes well, the FAA could give final approval by mid- to late April 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.
First, Boeing’s redesigned batteries have to pass a series of 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.
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 another 787 in Japan.
The airliner’s troubles have raised concerns that the FAA has ceded too much responsibility for evaluating the safety of new aircraft to manufacturers.
To save manpower, the FAA designates employees at aircraft makers and their subcontractors to conduct the safety testing of new planes.
Boeing’s battery testing concluded that short-circuiting wouldn’t lead to a fire and that the chance of a smoke event was one in every 10 million flight hours.
Instead, there were two battery failures when the entire fleet had clocked less than 52,000 flight hours.
UBS analyst David Strauss estimated that the 787 will cost Boeing $6-billion this year.
Besides the battery problems, the plane already costs more to build than it brings in from customers.