The U.S. agency that investigates air crashes on Thursday called for lithium-ion batteries on Boeing's 787 Dreamliners to undergo more testing to ensure they are safe.
The National Transportation Safety Board urged the Federal Aviation Administration to develop better tests for the uncontrolled overheating that led to a battery fire on a Dreamliner in 2013, require the tests for future aircraft designs, and check whether 787s and other planes that have the batteries need more testing.
The NTSB stopped short of calling lithium-ion batteries or planes flying with them unsafe. The batteries are widely used in cars, laptops and smartphones and have a tendency to overheat through processes that are not well understood by scientists.
The NTSB has not yet determined a root cause for the 787 fire in Boston in January 2013. No one was injured in the fire, or in two other 787 battery incidents, one in January 2014. Regulators grounded the 787 fleet for three months last year while Boeing designed a steel containment box and other measures to stifle battery fires on the innovative jet.
Boeing said it supports efforts to improve certification standards. The FAA was not immediately available to comment.
Boeing also said the tests it conducted in overhauling the 787 battery system last year "are fully consistent with the recommendations made by the NTSB today. We therefore remain confident in the safety and integrity of the comprehensive battery solution which was developed by Boeing, and approved by the FAA, last year."
Hans Weber, a former FAA adviser and president of consulting firm TECOP International, said the NTSB's recommendations were important to ensuring safety.
"It's a professional, serious step in dealing with new technology that has resulted in some scary failures," Weber said. "Whether the FAA acts on this one or not remains to be seen."
In calling for the changes before its fire investigation ends, the NTSB signaled safety could be improved and pressed the FAA to proceed without delay.
In a 12-page letter, the NTSB said it sought "to urge the FAA to take action" on its five recommendations, which include seeking advice from independent experts on new technologies well before they're authorized for use on aircraft.
The NTSB criticized testing the FAA, Boeing and battery maker GS Yuasa Corp <6674.T> of Japan relied on in certifying the batteries for use in the 787. Recent NTSB tests showed results are affected by environmental factors, such as how the battery was installed and the temperature of the air around it. Accordingly, the NTSB urged development of new tests that simulate an aircraft environment.
While the NTSB's letter focused on Boeing's 787, the board noted the Airbus A380 and Boeing 777 and 737 also have lithium-ion batteries.
Since certification tests for the various aircraft are not standardized, the NTSB advised the FAA to review testing used to support certification of other aircraft.
"Lithium-ion battery designs on airplanes currently in service might not have adequately accounted for the hazards associated with internal short circuiting," the NTSB said.
(Reporting by Alwyn Scott; Editing by Jeffrey Benkoe and Meredith Mazzilli)