The National Transportation Safety Board or NTSB on Thursday released an interim factual report relating to the investigation into the battery issues concerning Boeing Co.'s (BA) Dreamliner. The NTSB will hold a forum and a hearing in April to provide additional information to advance the probe.
The report says Boeing had done a functional hazard assessment as part of the 787 electrical power system safety assessment to determine the potential hazards that failures of electrical system components could result in.
It identified and classified two hazards associated with the main and APU lithium-ion battery - battery vents smoke/fire and battery vent and/or smoke (without fire).
Battery vents smoke/fire was classified as catastrophic while battery vent and/or smoke (without fire) was classified as hazardous. On the basis of the functional hazard assessment, Boeing defined three failure requirements for the main and APU lithium-ion battery.
Boeing's 787-8 electrical power system safety assessment included an analysis of lithium-ion battery cell failure modes. This analysis determined that overcharging was the only known failure mode that could lead to cell venting with fire.
As a result, Boeing established additional design requirements to ensure that chances of an overcharge event was extremely improbable.
As safety measures, Boeing added to the battery features such as thermal protection devices, circuitry to monitor cell and battery voltages and temperatures, circuits to ensure that cells in a battery are charged equally and within safe voltage limits. Components and circuitry that discontinue charging of the battery when conditions warrant this action were also added.
In January, All Nippon Airways said one of its Dreamliners made an emergency landing after smoke was detected in the high-tech plane's cockpit. The airline attributed the emission of smoke to a battery malfunction.
On January 16, the Federal Aviation Administration or FAA issued an airworthiness directive that led to all in-service 787s temporarily ceasing operations. According to the FAA, the 787 incorporated "novel or unusual design features," including the use of lithium-ion batteries.
The NTSB Thursday released an interim factual report and related documents in its ongoing investigation of the Japan Airlines 787 battery fire in Boston. The NTSB is examining the certification and testing of the 787 battery system as part of its investigation of this incident.
The NTSB's investigation into the probable cause of the 787 battery fire is continuing. It is also continuing to review the design, certification and manufacturing processes for the 787 lithium-ion battery system.
Further, the NTSB said it would hold a forum and a hearing in April to provide additional information to advance the probe.
The forum will explore lithium-ion battery technology and transportation safety, while the investigative hearing will focus on the design and certification of the 787 battery system.
BA closed up 2.5 percent on Thursday at $81.05.
by RTT Staff Writer
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