The Boeing 757 skidded off a runway at O’Hare International Airport on Sept. 22, the National Transportation Safety Board (NTSB) said. Although none of the 192 people aboard was injured, the pilots flew on backup battery power for long beyond the 30 minutes that their emergency handbook said the batteries would last, the NTSB said.
The pilots of the Seattle-to-New York flight drained the jet’s battery backup system, leaving inoperable vital systems that help stop a jet, according to a preliminary report released this week.
The pilots told investigators they had difficulty raising and lowering the jet’s nose and felt they had only one chance to land, the NTSB said.
“They should have landed as soon as practical,” said Michael Barr, an instructor at the University of Southern California’s Aviation Safety and Security Program. “That would have been the conservative approach. I don’t see why they thought they could fly all the way across country on their backup electrical system.
The pilots had switched to battery power shortly after leaving Seattle when electrical problems developed. The batteries last for about 30 minutes, but the pilots continued toward their destination until the jet’s electrical systems began failing about an hour and 40 minutes later.
The need to land as soon as possible when aircraft systems begin to fail has been reinforced by several accidents, such as Swiss Air Flight 111 in 1998, Barr said. The Swiss Air pilots attempted to diagnose where smoke was coming from before deciding to divert, Canadian investigators concluded. The jet became engulfed in fire and crashed off Nova Scotia, killing all 229 people aboard.
Last month, the American Airlines pilots had to stop the jet without thrust reversers and other devices that help a jet stop, the NTSB said. The electrical system failure was so complete that the pilots were unable to shut off the engines after they came to a stop, the report said.
Barr said investigators will want to know what the airline’s manuals and emergency documentation instructed pilots to do, what the airline’s maintenance department advised the pilots to do and how pilots were trained to handle electrical malfunctions.
American and its pilots union, the Allied Pilots Association, declined to comment while the case is under investigation.