American Airlines completed inspections of seat clamps on 48 Boeing 757-200s on 3 October, following multiple instances of rows coming loose in flight.
The Fort Worth-based Oneworld carrier says that repairs have been made where necessary and all of the aircraft are back in service.
"Over the next few weeks we will continue to work with the FAA [US Federal Aviation Administration] and all manufacturers involved to review the corrective action taken," says American. "We believe a contributing factor is with the seat tracking and locking mechanism, not with where the work was performed."
The airline indicated that a seat clamp that is used to secure rows of seats to the floor of the aircraft was the cause of the loose seats earlier this week.
The inspections 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.