A Boeing plan to redesign the 787 Dreamliner's
fire-plagued lithium-ion batteries has won approval from the Federal Aviation Administration (FAA), 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
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 FAA approves that type of plane as safe for flight.
The 787 fleet worldwide has been grounded
by the FAA and civil aviation authorities in other countries since January 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.
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.
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.
The FAA's approval of Boeing's plan "is a critical and welcome milestone toward getting the fleet flying again and continuing to deliver on the promise of the 787," Jim McNerney, the aircraft maker's CEO, said in a statement.
The 787 is Boeing's newest and most technologically advanced plane. Its grounding, an enormous black eye for Boeing, marked the first time since 1979 that FAA had ordered every plane of a particular type to stay out of the air for safety reasons.
On Tuesday, Boeing shares rose $1.22 to close at $84.16, and rose another 28 cents to $84.44 in aftermarket trading.