American Airlines has grounded 48 Boeing 757-200s to repair faulty seat lock plunger mechanisms, following multiple instances of seats coming loose in flight.

The Fort Worth-based carrier began pulling the aircraft on 4 October and says that the repairs will be complete by 6 October, with all of the 757s having returned to service at that time.

AA seat plunger

American Airlines

"Working with the FAA [US Federal Aviation Administration], American Airlines is taking additional steps to prevent seats from becoming dislodged on some of our Boeing 757 aircraft," says American. "American has instructed mechanics to pay particular attention to the seat lock plunger mechanism that secures the seat to the aircraft floor."

The airline had previously identified faulty saddle clamps for rows of seats on two 757s coming loose during flight. It said that all inspections were completed by 3 October.

American is cancelling up to a hundred flights following the decision to pull the 48 aircraft from service. This is in addition to continued delays and cancellations as a result of a contract dispute between the carrier and its pilots.

As of 3 October, only 54.6% of American's 12,484 flights had arrived on-time and 19% were delayed more than 44 minutes during the week beginning 30 September, according to The airline had a 54.6% on-time rate for the week ending 29 September and 48% for the week prior.

The seat repairs follow a row of seats becoming loose on two 757-200s. The first incident occurred in row 14 seats A, B and C during flight on American 2206 from Vail to Dallas-Fort Worth on 26 September, the same row then came loose after a flight from Dallas to Boston on the same day, and it came loose a third time during flight 443 from New York's John F. Kennedy (JFK) to Miami after which the aircraft returned to JFK on 1 October.

The problem was first identified on the second 757 in row 12 seats D, E and F on the ground in Miami on 27 September after which the clamps were tightened. The row came loose again in the air on flight 685 from Boston to Miami and the aircraft was diverted to JFK on 29 September.

The Transport Workers Union, which represents American's mechanics, has pointed to work conducted by third-party maintenance provider TIMCO for the loose seats.

TIMCO has declined to comment but says that it is working closely with the airline.

"We have confidence in our highly skilled maintenance and engineering teams as well our contract maintenance providers who have worked on all of the 757 aircraft involved," says American.

Source: Air Transport Intelligence news