The National Transportation Safety Board (NTSB) has not yet found out what caused the battery fire aboard the Japanese Airlines 787 Dreamliner in January at Boston’s Logan International Airport.
In an interim report released last week, the NTSB said it is planning to hold an investigative hearing in April to provide additional information with a focus on the design and certification of the 787 battery system.
Following the Jan. 7 incident in Boston, and several others on 787s operated by JAL and All Nippon Airways (ANA), FAA issued an airworthiness directive grounding all in-service Dreamliners in the United States, and carriers worldwide grounded their in-service 787 planes as well.
"With the grounding of the 787 fleet, concurrent international incident investigations, redesign and re-certification activities taking place simultaneously, it is essential to provide the aviation community, policy makers and the public with the factual information we are developing," said NTSB Chairman Deborah Hersman.
According to the report, during the 787 certification process Boeing performed a functional hazard assessment to determine the potential hazards that failure conditions of electrical system components could introduce to the aircraft during flight. The assessment determined that battery failurs resulting in smoke would occur about once in 10 million flight hours.
Prior to its grounding in January, the 787 had accumulated less than 52,000 flight hours; during that time two incidents involving smoke emission from a battery occurred, including the JAL fire in Boston and a separate incident currently being investigated by the Japan Transport Safety Board.
Boeing presented a proposed fix for the battery to FAA in February. The proposal would use sensors and circuitry to prevent the 787’s lithium ion battery’s eight individual cells from overheating and to protect the plane from damage if all the cells were to burn.
FAA has not yet ruled on Boeing’s proposal. More