The National Transportation Safety Board (NTSB) has released a lengthy report delving into the battery fire that grounded the entire Boeing 787 Dreamliner fleet last year. Though the agency doesn't explicitly identify the cause of the incident, it does name the Federal Aviation Administration (FAA), Boeing, and lithium-ion battery manufacturer GS Yuasa Corp. all as collective culprits for the fire, with regard to how the battery was manufactured and how it was permitted for use on the plane.

During the course of the review, the NTSB was able to determine that the battery wasn't damaged by environmental conditions or charged above normal levels. Instead, it concludes that the fire was caused by an internal short circuit within the battery itself. While the source of the short circuit isn't clear, the agency does suggest that GS Yuasa's manufacturing process allowed for significant defects that could have contributed to the incident. Moreover, Boeing and the FAA failed to conduct any audits of the manufacturer before the fire, allowing the defects to go through undetected. As a result, the NTSB issued 15 safety recommendations to the FAA, two to Boeing, and one to GS Yuasa.

In a statement sent to The Wall Street Journal, Boeing states that it agrees with the NTSB assessment, saying it is "confident in the comprehensive improvements made to the 787 battery system following this event." Indeed, the Dreamliner has flown without much in the way of incidents since early this year, though a smoking battery did set off alarms in Japan back in January.