Southwest grounds planes due to failed inspections

— -- Southwest Airlines on Wednesday grounded 38 jets in the midst of a federal probe of the low-cost carrier prompted by last week's $10.2 million fine for missed safety inspections.

Southwest canceled 126 flights by last evening, or about 4% of its daily operations, as it inspected older 737s in its fleet for cracks in the fuselage skin, Southwest spokeswoman Linda Rutherford said. The grounding was the largest since the government ordered emergency wiring inspections on 179 Boeing 737s on Mother's Day 1998.

The airline's own internal investigation discovered Tuesday night that Southwest had not properly examined the jets for cracks, Rutherford said.

"We made the decision to take a conservative approach, and we removed those aircraft from scheduled service," Rutherford said.

The airline expects all service to be back to normal by this morning, she said. Southwest had completed inspections on 28 planes but did not say whether it had discovered any cracks.

The action is the latest to tarnish the reputation of the airline that carries the most domestic passengers. Southwest has had only one fatal accident in its 37-year history.

Last Thursday, as the House transportation committee prepared to hold a hearing on oversight of the airline, the Federal Aviation Administration (FAA) hit Southwest with the largest fine in its history. The FAA charged that the airline intentionally operated at least 46 jets in March 2007 without required inspections for skin cracks.

Additionally, the airline and the FAA are under investigation by the Department of Transportation's inspector general because of allegations by two whistle-blowers that Southwest was allowed to bypass safety regulations.

The whistle-blowers alleged that Southwest had problems keeping up with safety inspections for years. Both men said they faced retribution from FAA employees for trying to enforce safety rules at the airline.

The FAA has acknowledged it did not adequately oversee Southwest and reassigned two employees. Southwest announced Tuesday that it had suspended three employees in connection with the fine.