American Airlines (AAMRQ) aircraft seats that dislodged in flight, causing the temporary grounding of 48 Boeing Co. (BA) 757s, already had been under closer scrutiny by the carrier for becoming loose sooner than others.
The airline initially blamed incorrectly installed saddle clamps before determining that a buildup of residue from spilled sodas, coffee and juice had kept locking pins from remaining in place, David Campbell, American’s vice president for safety, security and environmental, said in an interview today.
“We look every month because we have seen they were coming loose a little more than the average fleet we have,” he said. “We have a very aggressive maintenance program. There were just generally problems with the seat in terms of how it’s designed compared to later designs out there.”
The seat issues developed as the Fort Worth, Texas-based airline, operating in bankruptcy, struggled with delayed flights and tried to fend off a takeover attempt by US Airways Group Inc. (LCC) American, a unit of AMR Corp., canceled 94 flights yesterday and today while it carried out the inspections.
The seats, which have been used for years, differ from others because two locks are torque-tightened and two tightened by hand instead of all being torque-tightened. The manufacturer recommends inspections every 18 months, Campbell said.
The seats were designed and made specifically for American by Zodiac Aerospace’s Weber Aircraft Inc. unit in Gainesville, Texas. Robert Funk, vice president of sales and marketing for Weber, said in an e-mail that he couldn’t immediately respond.
The 757 inspections initially began after seat rows in coach sections worked free on three flights from Sept. 26 through Oct. 1. Seat rows were tightened multiple times on at least one of two planes involved, and one set of seats came loose enough to shift backward toward the next row. The seats never came completely loose from the floor, Campbell said.
The airline and U.S. Federal Aviation Administration are continuing an investigation into the incidents. American mechanics are installing a redundant locking mechanism to address the issue.
“We have a lot of confidence that this is what caused those events,” Campbell said. The seats are only used on 48 of the airline’s 102 757s.
American had completed repairs on 42 of the planes by noon Dallas time, and the airline expects to have all 48 planes back in service by tomorrow, Andrea Huguely, a spokeswoman, said in an e-mailed statement.
Maintenance workers had not previously discovered the buildup of “coking,” or the sugary residue, that allowed the pins eventually to work free and let the seats move, Campbell said. Seats normally are removed for various maintenance and the tracks cleaned.
“For some reason, coking has built up on these particular ones and created this problem,” Campbell said. “When a perfectly situated plunger is down and locked in, you can’t move the seat. But as the aircraft moves and torques, the plunger works back up because the locking pin wasn’t secured in place.”
Andreas Eichin was stuck in Bridgetown, Barbados, while trying to return to the U.S. from a business conference. His flight on an American 757 to New York’s Kennedy airport and then on to Washington Reagan was delayed two hours yesterday and subsequently canceled.
“We could see it on the tarmac,” Eichin said today while he was waiting for another American flight. “They said it was canceled because of a mechanical problem on board.”
Flight delays that began at the carrier in September and the seat woes built on labor unrest after American imposed concessions on pilots to help it restructure in bankruptcy and detailed plans to cut more than 4,000 jobs among mechanics and airport ground workers.
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