The National Transportation Safety Board recently concluded a two-day hearing into the problems with the lithium ion battery system used in Boeing's 787 Dreamliner. After several incidents involving the system, all 787s were grounded by the Federal Aviation Administration earlier this year. The hearing did not reach a conclusion as to the cause of the overheating batteries. The investigation into the overheating, including at least one situation where the batteries started a fire, is expected to continue for several months.
Part of the hearing was dedicated to a discussion of the standards for testing and re-testing the battery systems. Before the 787s began operating, Boeing estimated that the batteries could be expected to overheat once in 10 million flight hours. Instead, the first 52,000 flight hours led to several incidents of overheating. A fire at the manufacturer of the battery charger led the FAA to request that a new minimum performance standard be developed regarding the lithium battery systems. An independent advisory board, co-chaired by Boeing, developed a standard referred to as "Minimum Operational Performance Standards for Rechargeable Lithium Battery Systems."