US government officials are reviewing a Boeing proposal for a possible solution to the still-undiagnosed battery problems that have grounded the 787 fleet for more than five weeks.

Boeing Commercial Airplanes president Ray Conner today met with Michael Huerta, head of the Federal Aviation Administration (FAA), and deputy Transportation secretary John Porcari, to submit a proposal that reportedly could allow the 787 to resume operational service by late March.

After the meeting in Washington DC concluded, Boeing released a statement saying it is "encouraged" about making progress towards lifting the 787 grounding order imposed on 16 January.

The FAA, meanwhile, says it must analyse Boeing's proposal closely before it can make a decision.

"We won't allow the 787 to return to commercial service until we're confident that any proposed solution has addressed the battery failure risks," the FAA says.

Boeing's solution reportedly involves putting more spacing between the eight cells of the 32V lithium-ion battery made by GS Yuasa, improving the containment around the battery and venting any smoke or exhaust from the battery directly offboard the aircraft.

The changes appear aimed at preventing the thermal runaway condition that investigators in Japan and the USA have detected on two batteries that failed on different flights in January.

The ongoing investigation is still trying to understand what caused a short circuit to occur, which led to the thermal runaway problem. Under Boeing's proposal, the battery should not catch fire even if one of the cells experiences a short circuit.

Source: Air Transport Intelligence news