Southwest Airlines grounded 80 of its Boeing 737 aircraft Saturday after a harrowing incident in which a hole tore open in the fuselage of an airplane in flight, depressurizing the cabin and forcing an emergency landing.
Southwest spokeswoman Brandy King said the company canceled 300 flights across the country so Boeing engineers could help conduct inspections on the aircraft. The cancellations were felt throughout the airline's network, and it was unclear when the grounded planes would be returned to service.
Southwest is the top carrier at Tampa International Airport.
Investigators from the National Transportation Safety Board and the Federal Aviation Administration were still trying to determine what caused the fuselage to rupture on Flight 812 on Friday afternoon after it . The aircraft, which contained 118 passengers, safely made an emergency landing in Yuma, Ariz. It had just left Phoenix Sky Harbor International Airport for Sacramento, Calif.
Officials said the inspections could last for several days and they were looking for any indications that other planes were suffering from "aircraft skin fatigue."
Passengers described a terrifying and chaotic scene.
A "gunshot-like sound" woke Brenda Reese. Looking up, she could see the sky through a hole torn in the cabin roof.
Frightened passengers groped for oxygen masks as the plane made a terrifying but controlled descent. One passenger called it "pandemonium." Another watched as a flight attendant and a passenger passed out, apparently for lack of oxygen, their heads striking seats in front of them.
FAA spokesman Ian Gregor said the pilot made a "controlled descent from 36,000 feet to 11,000 feet altitude."
The pilot's safe emergency landing at a military base in Yuma, about 150 miles southwest of Phoenix, drew applause from relieved passengers.
"It was unreal. Everybody was like they were high school chums," said Christine Ziegler, a 44-year-old project manager from Sacramento, describing a scene in which passengers comforted and hugged each other after the plane was on the ground.
Southwest operates about 170 of the 737-300s in its fleet of about 540 planes, but it replaced the aluminum skin on many of the 300s in recent years, said another spokeswoman, Linda Rutherford. The 80 planes being grounded have not had their skin replaced, she said.
"Obviously we're dealing with a skin issue, and we believe that these 80 airplanes are covered by a set of (federal safety rules) that make them candidates to do this additional inspection that Boeing is devising for us," Rutherford said.
Southwest officials said the Arizona plane, a 15-year-old Boeing 737-300, had undergone all inspections required by the FAA, but they did not provide the date of the last inspection.
The 737-300 is the oldest plane in Southwest's fleet, and the company is retiring 300s as it take deliveries of new Boeing 737-700s and, beginning next year, 737-800s. But the process of replacing all the 300s could take years.
Metal fatigue was blamed for an 18-by-12 inch rip in a Southwest 737 last July while it was flying at 35,000 feet, also forcing an emergency landing. In 2009, a foot-long hole opened in the top of a jet while it was cruising at 30,000 feet, forcing an emergency landing in West Virginia.
That same year, the FAA fined the airline $7.5 million for nearly 60,000 flights in which the planes had not undergone required inspections for fuselage cracks.
This report contains information from the Associated Press and Los Angeles Times.