Southwest Airlines suspended three employees in response to government allegations it knowingly flew planes that had not been properly inspected for potential structural flaws, the carrier said on Tuesday.
The airline also said it would review its maintenance oversight practices with the help of an outside expert and make any changes to ensure that it is in full compliance with US safety regulations.
"These are important and necessary steps," Southwest Chief Executive Gary Kelly said in a statement.
Last week, the FAA proposed a record USD$10.2 million fine against Southwest for allegedly failing, over a period of several months in 2006 and 2007, to complete required aircraft safety inspections on 46 older Boeing 737s.
Safety and congressional investigators said the planes should have been grounded although the airline said at no time was the safety of any aircraft compromised.
Southwest said it was given clearance by the FAA and Boeing to fly the planes while it completed the routine checks for small fuselage cracks. Cracks were found on six planes and fixed.
Two senior FAA officials in Dallas, where Southwest is based, have been reassigned over the matter, the FAA said last week.
Kelly said Southwest took the latest action after an internal investigation. It did not identify the three employees or describe their duties but said they had been placed on administrative leave.
"I have insisted that we have the appropriate maintenance organizational and governance structure in place to ensure that the right decisions are being made," Kelly said.
In addition to the FAA, which is investigating another possible safety violation at Southwest, a congressional committee and the Transportation Department inspector general are conducting their own investigations.