The National Transportation Safety Board says that the investigation being done on the Boeing 787 Dreamliner’s lithium-ion batteries will conclude in March and final report will be submitted afterwards. A public hearing will also be conducted regarding the Japan Airlines incident in January of 2013 that triggered the investigation. Another battery failure incident prompted the Federal Aviation Administration to ground the fleet for one year.
An update given by the NTSB said that the investigative team have been doing work in Japan, the United States, France and Taiwan and said that, “as the investigation has progresses, the NTSB has been working closely with Boeing, the FAA, the Japan Transport Safety Bureau, the French BEA and technical advisors from Japan and France.” GS Yuasa, a Japan-based company, builds batteries for the 787, the first application of large-scale lithium-ion technology in a commercial aircraft and Thales builds the charging system.
In the Japan Airlines accident, the auxiliary power unit (APU) lithium-ion battery of the 787 caught fire after an internal cell failure while it was on ground in Boston on January 7, 2012 with no passengers or crew on board. A week later, the main lithium-ion battery on an All Nippon Airlines 787 failed while in flight, which caused the pilot to divert. This prompted the FAA to issue an emergency airworthiness directive on January 16 that grounded budding fleet of 50 aircraft and deliveries of new 787s.
Boeing, while waiting for the conclusion of the investigation by NTSB, developed fixes to the batteries, which includes a new container and venting systems and modified the system of charging of the batteries, all were approved by the FAA and used on the fleet. The aircrafts were flown and there were no reported main or APU batteries failure since then. But despite the solution Boeing found, NTSB continues its investigation on the design of the battery and operation and final report will probably include recommendations for Boeing and FAA to prevent further incidents with new technologies. On-going investigative work includes contact to Underwriter’s Laboratories for listing the thermal and electrothermal properties of the battery and “oscillatory testing.”
[via Aviation Week]