Southwest Airlines has grounded 79 of its Boeing 737-300 planes for inspection after one of its planes ripped open mid-flight on a flight Friday from Phoenix to Sacramento.
Sunday, 19 planes had undergone the intense inspection with no findings, and those planes have been returned to service, according to the airline. In three other airplanes, the testing did detect small, subsurface cracks. Further evaluation and potential repairs will be necessary before those planes are returned to service.
Southwest Airlines said Sunday evening it expects to cancel approximately 100 flights from its Monday schedule. The airline continues to inspect aircraft and will put those with no findings back into service. Southwest canceled approximately 300 flights each on Saturday and Sunday in order to conduct the inspections, according to the company.
Flight 812 was forced to land from 34,000 feet in the sky at a military base in Yuma, Ariz., due to the hole, which measured about 3 feet long in the roof of the passenger cabin. The pilots declared an emergency and brought the plane down 25,000 feet in less than five minutes.
No serious injuries were reported among the 118 people aboard, according to Southwest officials.
Federal Aviation Administration records obtained by the Associated Press show the 15-year-old plane had at least eight instances of cracking found in March 2010. The records also showed that the cracks in the aircraft frame, which is part of the fuselage, were repaired.
It's not uncommon for fuselage cracks to be found during inspections of planes that age, especially during scheduled heavy maintenance checks.
The FAA is investigating the mid-flight rupture. A piece of the fuselage will be examined, along with flight recorders.
Inspectors looking at the damaged plane found fatigue cracks in the metal near the area where the plane ripped open. It is not clear how those cracks got there or what role they played. Another concern is that the plane was damaged while being painted or during maintenance.
The plane had been through more than 39,000 takeoffs and landings, each putting stress on the aircraft's skin.
"When airplanes take off and land, aircraft that are pressurized, the internal cabin is expanded and contracts just a little bit," said ABC News consultant Steve Ganyard. "You're exercising the skin of that aircraft."
The inspections of the aircraft in question and other long-range jets has thrown air travel into somewhat of a nightmare for a lot of passengers. Flights out of Bob Hope Airport in Burbank to Baltimore, Las Vegas, Albuquerque, Kansas City and Salt Lake City have all been canceled.
At Los Angeles International Airport, there have been 38 outgoing canceled flights.
Travelers using Southwest Airlines were advised to check their flight status before heading to the airport.
The Associated Press contributed to this report.