U.S. and Japanese officials, working jointly to identify the fault after all 50 of the 787s currently in service were grounded, are now looking instead at a system that monitors the batteries’ charging levels and temperature.
A spokesman for Japan’s transport ministry reported “no major quality or technical problem" with the batteries themselves, but said, "We are looking into affiliated parts makers. We are looking into possibilities."
Two aircraft, operated by Japan Airlines and All Nippon Airways, suffered smoke damage in the same week as a result of their batteries overheating.
Analysts said the problem was clearly electrical, but the longer it took safety officials to pin down the exact cause, the longer the 787 would be out of service–with potential impact on future deliveries.