Dreamliner Lithium Battery Fire Cause Still Unknown

An interim report shows that US safety regulators have not uncovered the reason yet for the Boston lithium-ion battery fire that has led to the grounding of all 50 Boeing 787 Dreamliners.

The National Transportation Safety Board (NTSB) report, released last week together with related documentation, includes more than 500 pages of laboratory analyses, interviews, and other data.

Though it gives a detailed description of the Jan. 7 battery fire, in which one firefighter was injured, the report does not explain it.

In that incident, cleaning staff in the cabin of a Japan Airlines Boeing 787 parked at Boston’s Logan International Airport found smoke coming from the auxiliary power unit battery case.

A second battery fire forced the evacuation of an All Nippon Airways flight at Takamatsu Airport in Japan nine days later. The Federal Aviation Administration (FAA) then ordered airlines to ground their fleets of Boeing 787s until the plane’s onboard batteries are proven safe.

Thick smoke
The report documents:

• How maintenance personnel discovered the Boston fire and how firefighters responded to it
• Findings from the examination of the battery and related components
• Initial reports on the flight recorder data
• The 787 electrical power system certification plan
• Ongoing and planned investigative activities

According to the BBC, the incident was more serious than previously thought. Fire crews needed an hour and 40 minutes to extinguish the fire; the smoke was so thick they could not see the battery.

A fire captain said in the report that the battery was hissing loudly, and liquid was flowing down the sides of the battery case. Another firefighter said he heard a popping sound, and smoke began pouring out of the aft bay. The fire captain’s neck was burned when the battery exploded.

The report offers no conclusions or recommendations, and the NTSB’s investigation continues. Chairman Deborah Hersman said in a press release that the NTSB will hold a forum to explore lithium battery technology, as well as a public hearing on the design and certification of the 787 battery system. Both the forum and the hearing will be held in April and will be webcast live and open to the public.

Boeing losing $200 million a month
Meanwhile, Boeing is hoping the FAA will soon accept the proposals it sent in February to address the risk of fire, so that it can get its Dreamliners tested and flying again. The proposed changes include putting batteries inside fireproof metal cases and widening the gaps between battery cells to prevent overheating.

The company is reportedly losing $200 million a month in delivery payments while spending $1 billion a month to keep its production running.

The Dreamliner fleet is scattered at 17 airports worldwide, waiting for the green light. A decision from the FAA is expected in the next few days.

Airbus said last month that it will not use lithium batteries in its A350 planes because of the problems that have grounded Boeing’s planes. It will use traditional nickel-cadmium batteries, even though its test flights are still using lithium batteries.

Lithium batteries overheat faster
Lithium-based batteries have a higher propensity to heat up and ignite than other types of batteries if they short-circuit or are overcharged. They are the main type of rechargeable battery used in many electronic devices, including laptops, iPads, notebooks, smartphones, and electric cars.

Japanese regulators are investigating the lithium battery fire at Takamatsu Airport. Let us hope they will be able to come up with a cause sooner, rather than later.