Southwest Airlines inspecting planes after crack forces emergency landing

One of the nation's largest discount air carriers said it was inspecting 79 of its airplanes after one of its fleet was forced to make an emergency landing Friday night after cracks were discovered in its fuselage.

The inspections resulted in about 300 Southwest flights being canceled Sunday, the airline said, and more delays are expected Monday.

"Our highest priority is the safety of our employees and customers," Southwest Vice President Mike Van de Ven said in a statement over the weekend.

"Prior to the event regarding Flight 812, we were in compliance with the FAA-mandated and Boeing-recommended structural inspection requirements for that aircraft," Van de Ven continued. "What we saw with Flight 812 was a new and unknown issue. We regret any customer inconveniences as a result of the inspections currently under way. Delays and cancelations are never the preference; however, we are taking every precaution we can to ensure that our operation is safe."

At issue is a Friday flight from Phoenix to Sacramento. Less than an hour into the flight, the plane, a Boeing 737, was forced to make an emergency landing at an Air Force base in Yuma, Ariz., after its cabin lost pressure. None of the 118 passengers and five Southwest employees on board the flight was injured.

The National Transportation Safety Board and Federal Aviation Administration have begun investigating the incident.

Southwest said it operates about 300 737s overall, but only 79 were in the same subgroup of aircraft as the plane that was forced to make the emergency landing.