Round 9 is compliance and agreement by Boeing on these findings. Correction are completed and become part of the Boeing LION engineering process.
Round 10: Knockout of the problem, a high level of reliability is established with a high number of airplanes and a higher number (million) of flights with no problems.
Dreamliner battery fire triggered by Boeing design, probe finds
Chicago Tribune link: Alan Levin, Bloomberg News
"Inadequate design and testing caused last year's battery fire that led to the grounding of Boeing's Dreamliner jets for more than three months, investigators concluded."
The FAA faulty trail:
- "The fire occurred Jan. 7, 2013, while a Japan Airlines 787 Dreamliner sat at Boston's Logan International Airport. Boeing uses two lithium-ion batteries in the Dreamliner to power electronics and other equipment. It was a short circuit in one of the battery's eight cells that triggered a runaway failure that engulfed the entire power pack, the NTSB said.
- Cells may overheat when large amounts of power are being drawn and better protections should be installed, the NTSB said.
- The Japan Transport Safety Board found in a Sept. 25 report an internal short-circuit "was probably" at fault though it was impossible to say what prompted it.
- As part of that design, Boeing installed two lithium-ion batteries, which hold more energy and last longer than older technology. Those factors also make them potentially more dangerous because they are made with flammable chemicals and contain enough energy to self-ignite if they malfunction.
- Boeing had estimated that the chances of a single cell on one of its 787 batteries failing and venting flammable chemicals was one in 10 million. When the second failure occurred in Japan, the aircraft had flown just 52,000 hours, according to the NTSB.
- This miscalculation was part of a cascading series of failures in the design and certification process, the safety board concluded.
- The battery tested for possible failure by GS Yuasa wasn't the same as the ones installed on the Dreamliner fleet and the tests didn't anticipate the most severe conditions seen in service, the investigation found.
- An inspection of GS Yuasa's manufacturing plant by the NTSB found evidence that foreign debris was allowed to contaminate batteries, "which could lead to internal short circuiting."
- The company's inspections also couldn't detect other internal defects capable of producing short circuits. The report didn't blame those issues for the fire.
- Boeing also failed to anticipate the battery's risks, the NTSB said. The company's engineers didn't even consider the potential for a single cell overheating and igniting adjoining cells, according to the report.
- The FAA didn't give its inspectors sufficient guidance on overseeing the battery design and the agency lacked expertise, according to the NTSB.
- The safety board has no regulatory authority and must rely on non-biding recommendations to improve safety.
- In response to earlier recommendations, FAA Administrator Michael Huerta told the NTSB that the agency is studying additional battery test requirements, according to an Aug. 19 letter. The agency is working with RTCA Inc., a Washington-based nonprofit that advises the FAA on technology."With assistance from Julie Johnsson in Chicago.
Boeing has narrowed the voltage regulation parameter of power entering the battery. Power surging is mitigated, allowing only a power stream within safe limits. Boeing has gone to the battery maker requiring a tighter inspection and testing of the battery construction. Special monitoring is enacted for foreign debris within the cells, and its detection of extremely small battery faults found during manufacturing. Boeing has taken extra measures for catastrophic battery failure during operation, protecting customers and crew from any battery failure. Since batteries are primarily used on the ground under static configuration, the 787 flies with direct power from its engines without battery backup. During a catastrophic failure of engine power or battery failure, the 787 can apply fly with RAT air power or auxiliary electrical engine power, supplying electrical power to its systems until a crises resolution is found. Aircraft today have redundancy making the battery obsolete during flight and final approach. The current Boeing battery protection is an overbuilt mitigation of its underestimated engineering faults now under review and implementation of redesign.