The National Transportation Safety Board (NTSB) released its fourth update regarding its investigation of Japan Airlines Co Ltd (TYO:9201)  Boeing 787 parked at the Logan International Airport in Boston, which caught fire on January 7th.

Boeing 787

According to NTSB, the fire blazed after the airplane landed at the airport, no passengers or crew were onboard the aircraft. The Boeing 787 was delivered to Japan Airlines Co Ltd (TYO:9201) on December 20th last year, and it only logged 169 flight hours with 22 cycles when two of its lithium ion batteries caught fire. Investigators identified GS Yuasa as the manufacturer of the auxiliary power unit battery used in the Boeing 787.

In addition, the NTSB said investigators have continued disassembling the components of the APU battery, they started disassembling the last eight cells at the NTSB Material Laboratory in Washington. They are also examining the cell elements with a scanning-electron microscope and energy-dispersive spectroscopy.

Furthermore, NTSB investigators said, “A cursory comparative exam has been conducted on the undamaged main battery. No obvious anomalies were found.” According to them, the main battery will undergo a more detailed examination. Investigators will conduct a thorough tear down and test sequence series of nondestructive examination.

Moreover, the NTSB assigned two investigators to participate in the Federal Aviation Administration (FAA) comprehensive review. One of the investigators will test Boeing’s cause corrected action efforts. The other investigator will take part in the on-going FAA review on the battery and battery system special condition compliance documentation.

The Boeing 787 was  grounded worldwide due to risk of a fire breakout. Last January 18, Japanese investigators theorized that excess voltage was the cause of problems in the Boeing 787, after discovering that a flammable battery fluid, known as electrolyte, leaked from the main lithium-ion battery of the airplane beneath the cockpit.

Last week, NTSB Chairman, Deborah Hersman said investigators found a series of symptoms, but failed to identify the underlying cause of the battery damage of the Boeing 787  on January 7th. The NTSB chairman said investigators will also examine the design of the battery compartment area and the agency will evaluate whether the certification standards have been strong enough. According to her, the investigation could take more weeks, the decision as to when Boeing 787 could fly again depends on the FAA.