Yikes !
from WSJ extract
A Federal Aviation Administration safety directive that became public on Thursday reveals that Boeing’s laboratory tests discovered that under certain circumstances, all of the 787’s power systems can suddenly shut down entirely during a flight.
Such a problem, —which the FAA said risks “loss of control of the airplane,” can occur after a jetliner remains connected to onboard or ground-based electric power without a break for a stretch of 248 consecutive days, the agency said. The FAA is ordering airlines to shut down power systems periodically to alleviate the hazard.
Boeing said such shutdowns are part of regular maintenance, and it would be rare for a jet to have power uninterrupted for so long. The plane maker roughly a week ago recommended that airlines voluntarily turn off power systems at least every four months.
During the early stages of the plane’s introduction, Boeing drafted an internal report concluding that Dreamliners experienced most of their reliability problems just after being powered up. The company recommended adding additional time before flights to deal with erroneous “nuisance” messages.