WASHINGTON — Boeing is proposing a long-term fix for the 787 Dreamliner’s troubled batteries that will keep them grounded until April at the earliest, congressional officials said Friday.
A Boeing Commercial Airplanes team led by CEO Ray Conner was scheduled to present the plan in a meeting Friday with Michael Huerta, head of the Federal Aviation Administration. The airliners, Boeing’s newest and most technologically advanced, have not been allowed to fly since mid-January following a battery fire in one plane and a smoking battery in another.
The plan calls for revamping the aircraft’s two kinds of lithium ion batteries to ensure that any short-circuiting that could lead to a fire won’t spread from one battery cell to the others, officials said. That would be achieved by placing more robust ceramic insulation between each of the battery’s eight cells. The aim is to contain not only the short-circuiting, but any thermal runaway, a chemical reaction that leads to progressively hotter temperatures.
The additional spacers will enlarge the battery, requiring a bigger battery box to hold the eight cells. That new box would also be more robust, with greater insulation along its sides to prevent any fire from escaping, officials said.
The plan will require testing and partially recertifying the safety of the plane’s batteries, said the officials, who spoke on condition of anonymity because they weren’t authorized to speak publicly.
The testing and recertification will take time, with engineers currently estimating completion sometime in April, they said.
It’s up to Huerta to decide whether to approve the plan. But Boeing’s plan is not a surprise, since the company has kept regulators closely informed, the officials said.
Boeing, the FAA and the National Transportation Safety Board still have not identified the root cause of a Jan. 7 fire that erupted in an auxiliary power unit battery of a Japan Airlines 787 about a half hour after the plane landed at Boston’s Logan International Airport. The safety board is investigating that incident.
Engineers and battery experts gathered by Boeing developed a list of possible causes for the fire and a plan to modify the batteries to address the spread of a fire created by any of those causes, officials said.
After the Jan. 7 fire and an emergency landing by an All Nippon Airways 787 in Japan, the FAA and aviation authorities overseas ordered the planes grounded. There are a total of 50 of the planes in the fleets of seven airlines in six countries.
On Thursday, United Airlines cut its six 787s from its flying plans at least until June and postponed its new Denver-to-Tokyo flights as airlines continued to tear up their schedules while the plane is out of service. United is the only U.S. carrier with 787s in its fleet.
Among the many unanswered questions is how the 787 battery problems will affect Boeing’s effort to win FAA permission for the planes to make flights that venture further from the nearest airport, such as those that travel over wide expanses of ocean. The FAA has tighter requirements for such flights in twin-engine planes because it wants to make sure the plane can keep flying if it loses an engine or encounters other problems far away from a safe landing.
Until it was grounded, the 787 could fly up to three hours away from the nearest airport. That’s far enough for flights between the U.S. and Europe and some flights over the Arctic, for instance. But Boeing wants permission for flights up to 5.5 hours from the nearest airport. Its 777 is already certified for such flights.
Boeing said last month that it was close to submitting a plan for those longer flights.
Freed reported from Minneapolis.