The incident involving Japan Airlines Boeing 787-8 JA829J happened on 7 January 2013 and was caused by a fire coming from underneath the lid of an auxiliary power unit battery case. The incident prompted an investigation and a suspension of the battery units pending the evaluation of the incident. The conclusion was that the device’s engineering and manufacturing processes were the causes of potential conflagration, with Boeing engineers blamed for not providing contingencies for the worst-case scenario.
The review of the manufacturing process indicates that Boeing did not produce the battery themselves but rather outsourced its production to Japan – a common practice for high-tech production, which Japan has the industry for. The subcontractor was GS Yuasa and Securaplane, which were to build the power battery unit according to the company’s specifications. This choice alone brings the potential for error and reduced oversight, as Boeing cannot directly control and observe the manufacturing process. The matter was made more complicated when Yuasa contracted another company, KAI, to produce the BMU, adding a tertiary subcontractor into the process.
The quality control process was done according to FAI methodology. The intent of the FAI was to determine if a vendor’s product met acceptance and quality control requirements to ensure that all engineering, design, and specification requirements were correctly understood, accounted for, verified, and recorded. As it was discovered after the incident, the provided FAI report was erroneous, as the supervision and observation of subcontractors were done poorly. 17 components were made not according to Boeing’s specifications, and have contributed to increased flammability. GS Yuasa also conducted its own tests during the manufacturing processes of the power cell, with less than 1% of all products being rejected due to test results. The primary method of finding any errors in the cell’s interior is through the use of a CT scan, which could detect any micro-welding defects and similar issues that have the potential of hurting the unit. Boeing’s oversight over these processes was slim if any.
Based on these findings, it could be concluded that while the process of designing, manufacturing, and testing the device looked good and proper on paper (all the necessary certificates were acquired), in practice the use of different subcontractors created a discrepancy in quality. At the same time, Boeing had very little hands-on control over the quality of the manufacturing process, the procured materials, or the testing of the finished product.
I would make a recommendation to the FAA to increase the involvement of Boeing during all stages of cell production if they plan on outsourcing the production of this critical element. The number of subcontractors and tertiary parties should be minimized – preferably, all work should be done full-cycle on a singular plant, thus eliminating the chance of damaging the materials during transportation. Second, it would allow easier access for Boeing inspectors to all the production processes to ensure the power cells are built in accordance with specifications. Any design oversights that caused overheating should be fixed, with redundant measures added in an event of a battery short-circuit and failure.
These recommendations are to be added to the ones already issued by the FAA, which include proper stress and abuse tests, measurable criteria for quality, and close cooperation between the producer as well as the US government, laboratories, and quality control services. The optimal scenario would be for Boeing to develop a full cycle for cell production of their own, rather than moving it overseas, where the hands-on control of the processes is slim by default. The US has the proper production plants and facilities to accomplish this, with any extra costs paid off by increased safety and reliability of the product.