Friday, January 25, 2013
NTSB to Make Safety Recommendations for Boeing 787 Dreamliner
National Transportation Safety Board (NTSB) Chairman Deborah Hersman on Thursday said her agency will issue recommendations for safety improvements on Boeing’s 787 Dreamliner plane as it continues to investigate the recent electrical fire that occurred on a Japanese Airlines (JAL) 787 at Boston’s Logan International Airport earlier this month.
Hersman held a press conference Thursday to provide an update on the ongoing investigation that her agency is conducting along with FAA, Boeing and the Japanese Transportation Safety Board (JTSB) into a recent string of incidents involving the Dreamliner. FAA issued an airworthiness directive to ground all in-service Dreamliners after JAL and another Japanese carrier — All Nippon Airways — experienced an electrical fire and several fuel leaks while flying the plane on commercial flights.
NTSB investigators have determined that the lithium ion battery on the JAL Dreamliner experienced a short circuit and a thermal runaway, in which a “significant temperature increase can initiate a destructive chain reaction,” according to NTSB. However, the investigators are not clear as to what occurred first or what caused these two outcomes.
"These events should not happen as far as design of the aircraft. There are multiple systems to protect against a battery event like this. Those systems did not work as intended, we need to understand why," said Hersman.
The Dreamliner batteries are a product of Japanese manufacturer GS Yuasa, and are unique to the plane, as they are used as both the main battery and the battery that powers the auxiliary power unit, which is the one that caught on fire in Boston, NTSB said.
The JAL’s flight data recorder has also been examined, and it has been determined that the battery was not overcharged.
The investigation is ongoing with experts from NTSB, Boeing, FAA and NTSB conducting tests on the batteries and other critical components of the plane at facilities in Washington D.C., Arizona, Seattle and Washington. Going forward the investigation will include “examination of the battery elements with a scanning-electron microscope and energy-dispersive spectroscopy to analyze the elemental constituents of the electrodes to identify contaminants or defects,” NTSB said.
Hersman was not able to provide an estimated return to service for Dreamliners operated by carriers in the U.S. or around the globe.
“One of these events alone is serious; two of them in close proximity, especially in an airplane model with only about 100,000 flight hours, underscores the importance of getting to the root cause of these incidents,” said Hersman. More