By the CNN Wire Staff
The Texas-based airline grounded 79 planes for inspection after a hole opened on top of a Boeing 737 mid-flight Friday.
It canceled approximately 600 flights to accommodate the inspections: 300 on Saturday and 300 flights on Sunday.
So far, investigators have found indications of cracks in three other aircraft, the National Transportation Safety Board said Sunday.
Of the planes inspected, 19 had returned to service by Sunday afternoon, the airline said.
The airline advised customers to check the status of their particular flight or rebook their trip before heading to the airport.
Inspections of the aircraft are expected to be completed by late Tuesday.
In the Friday incident, the plane had taken off from Phoenix and was headed to Sacramento, California. Eighteen minutes into the flight, the hole — 5 feet long and 1 foot wide — opened, causing the cabin to lose pressure, the safety board said.
One flight attendant received minor injuries, the agency said.
The pilot initially planned to return to Phoenix to land, but he made an emergency landing at a military base in Yuma, Arizona, after flight attendants reported seeing blue sky through the jet’s roof, the safety board’s Robert Sumwalt told reporters.
Boeing is sending a service bulletin to airlines with recommendations for how to inspect their planes for similar cracks, the safety board said.
Meanwhile, some of the 118 passengers who were aboard the crippled Boeing 737 said they feared for their lives.
“We were in shock,” passenger Debbie Downey said Saturday. “We were in row 16 and my husband and I could see blue sky … the wiring, the cabling. It actually was terrifying.”
Passenger Greg Hansen said passengers panicked and screamed as the sun shone through the cabin.
“Most people were just white knuckles holding onto the arm rests,” he said.
The airline said it provided a full refund, an apology and two complimentary round-trip passes on the airline for future flights.
Boeing spokeswoman Julie O’Donnell declined to comment on possible causes of the incident.
“Boeing is committed to ensuring safe flight and to supporting our customers,” the company said in a statement. “We are working closely with Southwest and are providing technical assistance to the U.S. National Transportation Safety Board as it investigates the incident.”
A total of 288 Boeing 737-300s are currently operating in the U.S. fleet, and 931 operate worldwide, according to the Federal Aviation Administration.