Southwest says 4 jets needed repair

Southwest Airlines Co., facing a $10.2-million fine for possible maintenance violations, said surface cracks were found on four of 44 aircraft grounded to verify that required inspections were done correctly.

Thirty-eight of the airline’s older model 737s were being used for flights when they were taken out of service to be reinspected. Thirty-four have returned to flying, and the four being repaired should be back in the air by this weekend, Southwest said.

The groundings occurred as the Dallas-based carrier prepared to respond to Federal Aviation Administration claims that it flew planes last year that had not undergone required safety checks.