NTSB: Cracks found in 3 grounded Southwest planes

The 5-foot-long hole tore open in the passenger cabin roof area shortly after the plane left Phoenix for Sacramento, Calif., Friday afternoon. None of the 118 people aboard was seriously hurt as the plane descended from 34,400 feet to a military base in Yuma, 150 miles southwest of Phoenix.

Since then Southwest grounded its 79 other Boeing 737-300s and began inspecting them.

The airline said in a statement Sunday that two planes have been found to cracks similar to those in the stricken aircraft and will be evaluated and repaired before they are returned to service. A National Transportation Safety Board member told The Associated Press later that a third plane had been found with cracks developing.

The other 19 aircraft inspected so far showed no problems and will be returned to service.