National Transportation Safety Board (NTSB) issued a series of recommendations on the evaluation and certification of lithium-ion batteries for use in aircraft systems, as well as the certification of new technology.
The five safety recommendations, addressed to the Federal Aviation Administration (FAA), are derived from NTSB's ongoing investigation of the Jan. 7, 2013, fire that occurred in a lithium-ion battery on a Boeing 787 parked at Boston Logan Airport.
According to investigators, the battery involved in the Boston 787 fire showed evidence of not only an internal thermal runaway but also unintended electrical interactions among the cells, the battery case, and the electrical interfaces between the battery and the airplane.
The agency points to a gap in standardization of thermal runaway tests, which render the processes used in the 2006 to support the certification of the lithium-ion battery designed for the 787 inadequate. Furthermore, due to the lack of a standardized thermal runaway tests, lithium-ion battery designs on airplanes currently in service might not have adequately accounted for the hazards associated with internal short-circuiting.
In its examination of the challenges associated with introducing newer technologies into already complex aircraft systems, the agency stated that including subject matter experts outside of the aviation industry "could further strengthen the aircraft certification process" by ensuring that both the FAA and the aircraft manufacturer have access to the most current research and information related to the developing technology.
To address all of these issues, the NTSB asked the FAA to do the following:
- Develop an aircraft-level thermal runaway test to demonstrate safety performance in the presence of an internal short circuit failure
- Require the above test as part of certification of future aircraft designs
- Re-evaluate internal short circuit risk for lithium-ion batteries now in-service
- Develop guidance for thermal runaway test methods
- Include a panel of independent expert consultants early in the certification process for new technologies installed on aircraft
NTSB estimated the final report on the January 2013 Boston 787 battery fire investigation will be released in the fall.
Click here for more information on the safety recommendation letter to the FAA.