Those aboard described a terrifying experience that started when a piece of a jet engine apparently flew into a window, shattering the window and depressurizing the plane.
Passenger Matt Tranchin told NBC News that about 20 minutes after takeoff, he heard something that sounded like an explosion.
“There was an explosion of the engine. A shard of the engine hit the window,” said Tranchin, 34, of Dallas. “The plane dropped immediately. Our oxygen masks dropped immediately.”
Tranchin said he was sitting in Seat 17E — three rows behind the window that was struck by the engine debris. The passenger next to the broken window was hit by glass and “covered in blood,” he said.
After the window blew out, flight crew prepared for a crash-landing, Tranchin said.
“As we landed, they kept repeating ‘Brace for landing! Brace for landing!’ ” he said.
While the plane sped toward the runway, Tranchin sent frantic goodbye messages to his family.
“My wife is in her third trimester,” he said. “We’re expecting our first child. It was one of those things when you don’t want to terrify your family, but if you do go down, you don’t want to not say goodbye.”
Southwest said there were 143 passengers and five crew members aboard the Boeing 737. The condition of the passengers was not immediately known.
“We are in the process of gathering more information,” Southwest said in a statement. “Safety is always our top priority at Southwest Airlines, and we are working diligently to support our customers and crews at this time.”
Images of the plane showed an engine appearing exposed and shredded. It wasn’t immediately clear what caused the damage.
“This appears to be what aviation officials call an uncontained engine failure,” NBC News aviation specialist Jay Blackman said. “Engines are designed, when they fail, to fail inside the engine cowling. But in this case it looks like it pierced the cowling, and not only the cowling, but it pierced part of the fuselage.”
Philadelphia airport officials said the flight was diverted due to an “operational event” but did not give any more information.
The FAA issued a temporary ground stop for all other flights at the Philadelphia airport and told passengers to expect delays.
The National Transportation Safety Board will lead the investigation into what happened, the FAA added.
Passengers on the Philadelphia tarmac could be seen exiting the damaged plane through a mobile stairway before being bused to a terminal.
Tranchin said that once the flight landed, everyone burst into applause.
“There was a lot of hugging,” he said. “I personally hugged the pilot. I think just relief, relief that we get to live for another day.”