Friday, March 08, 2013 4:03 am
Boeing 787 battery fire was difficult to control
By JOSHUA FREED and JOAN LOWYAssociated Press
Six bolts held it fast. A quick-disconnect knob - just a quarter turn would pop the battery free - had melted away. Firefighters with gloved hands tried to turn the bolts with pliers, which is like trying to slice an onion with a rubber spatula while wearing oven mitts. The thing wasn't budging. A pry bar bent the battery's case but didn't move it.
They finally cut it loose with a battery-operated tool and, using straps, hauled the 63-pound, still-smoking battery about 50 feet from the aircraft.
The National Transportation Safety Board on Thursday released 547 pages of reports and supporting materials about its investigation of the Jan. 7 fire. The documents show firefighters struggling to tame a small but worrisome fire that has left investigators relieved that it happened after a flight and not during one.
Another smoldering battery nine days later in Japan prompted the grounding of 50 787s worldwide. Investigators still don't know the root cause.
Other than the firefighter's injury, neither incident hurt anyone. But fire is a major threat to any airplane's safety. Before the incidents, Boeing categorized flame from the 787 battery as "catastrophic," prompting it to build in extra safeguards designed to prevent a battery fire. It was thought that the only way the battery would burn would be if it was overcharged, according to one NTSB report, which cited Boeing's earlier testing.
Boeing estimated the likelihood of a smoke incident as one in every 10 million flight hours for the 787 fleet. In January there were two when the fleet had only 52,000 hours.
The new NTSB documents also showed:
-Boeing did some testing itself, but much of the testing on the 787's battery system was done by Thales of France, which made the 787's electrical system, and by battery maker GS Yuasa of Japan.
-The plane's air system, designed to vent smoke outside if there's a fire, didn't work because the plane had lost power when the fire started. Firefighters reported smoke all the way up in the cockpit at one point.
-A Japan Airlines mechanic who was the first to deal with the fire reported seeing 3-inch flames in two spots on the battery, but only smoke was seen by firefighters who arrived a minute later.
The NTSB's investigation continues and the agency plans two public hearings next month. Meanwhile, the Federal Aviation Administration is deciding whether to accept Boeing's plan to add more insulation and other improvements that would contain a fire. Boeing's plan would require testing and then FAA approval, and the 787 isn't expected to return to flying until April at the earliest.
The Jan. 7 flight from Tokyo had gone normally. First its 184 passengers, then the pilots got off the plane. Airplane cleaners came on board.
With just a handful of ground workers on the plane, the auxiliary power unit, which provides power on the ground, shut down. This got the attention of the cleaners and maintenance workers because all of the cabin lights and in-flight entertainment systems went dark. JAL mechanic Kazuyuki Sato prepared outside power lines in case the plane needed them for electricity.
Then a cleaner said she saw smoke by one of the plane's kitchens. Twelve seconds later, she and a worker in the cockpit left. Sato, moving toward the plane's electronics bay, radioed that he found heavy smoke there, and readied a fire extinguisher.
At the gate, someone called the fire department.
Sato saw flames from the battery and blasted it with the fire extinguisher. The compartment "was dark and very smoky," according to the NTSB's account of its interview with him. It was a "dangerous environment in the compartment" and he couldn't continuously point the extinguisher at the fire. Eventually, though, he emptied all 20 pounds of the extinguisher's contents onto the fire. The flame didn't stop.
The airport fire incident commander ordered every fire truck toward the JAL plane. It's not clear whether they knew all the passengers were off. Even if no one is in immediate danger, a $200 million smoldering airplane parked next to a busy airline terminal brings a speedy response from firefighters.
While four trucks raced toward the plane, Engine 3 was already nearby because of a medical call. A fire lieutenant inside the airport ran toward the gate where the JAL plane was parked, telling the fire truck's driver to head that way. Firefighters from Engine 3 grabbed a hose, climbed the stairs in the jetway and headed into the plane.
An airport fire commander called for additional help from Boston's fire department.
The first firefighter to enter the plane saw "a white glow about the size of a softball" through the smoke using his hand-held heat-imaging camera. He applied another type of fire extinguishing agent, which somewhat reduced the glow. An airport security camera video showed white smoke billowing from the underside of the plane.
Another firefighter reported "no visibility" because of the smoke and directed another burst from a fire extinguisher at a hot spot, but the battery seemed to rekindle. A fire captain applied the extinguisher again for about five minutes, reducing the fire. But the battery was still emitting heavy smoke and hissing loudly. Liquid was flowing down its side. Lithium ion batteries, unlike the batteries used on other planes, contain a flammable electrolyte.
A fire captain reported that at one point the battery "exploded," injuring his neck.
It took 80 minutes from when the first fire call came in until the battery was hauled out of the plane. Firefighters sprayed 740 pounds of the firefighting agent Halotron as they tried to put the battery fire out.
Investigators later found little balls of melted and cooled stainless steel, apparently from the cases of the battery's eight cells. It melts at 2,700 degrees Fahrenheit, one document noted.
The 787 is Boeing's newest and most technologically advanced plane. It relies on electric systems to a greater degree than any other airliner. And it is the first airliner to make extensive use of lithium ion batteries, which are lighter, recharge faster and can hold more energy than other types of batteries.
ANA confirmed this week that it replaced three circuit boards located in 787's electronics bay after pilots received an error message during flights in March, April and June of last year. One of those circuit boards had a "slight discoloration," said ANA spokeswoman Nao Gunji. Nothing wrong was found with the other two, but they were replaced as a precaution, she said.
Norwegian Air Shuttle, which was due to receive 787s this year, said it will lease two Airbus A340s along with flight crews if it doesn't get its 787s on time.
Boeing Co. is still building 787s, but deliveries are halted. It has not said how much the battery problems will cost.
Freed reported from Minneapolis and Lowy from Washington.
Follow Joan Lowy at http://www.twitter.com/AP-Joan-Lowy