New details about what happened aboard deadly Southwest flight

PHILADELPHIA (CBSNews) -- Federal investigators said Wednesday an engine crack caused a deadly blow-out on a Southwest Airlines jet. CBS News has also learned the woman who was nearly sucked out of the plane's broken window Tuesday was wearing a seatbelt.

Philadelphia's medical examiner said Wednesday that Jennifer Riordan died of blunt impact trauma to her head, neck and torso.

Spokesman James Garrow of the Philadelphia Department of Public Health said Wednesday evening that Riordan's death was ruled accidental.

Investigators describe a 22-minute flight of terror as the Southwest 737's left engine blew out at about 32,500, sending the plane into a 40 degree bank to the left. The NTSB believes metal fatigue lead to a engine fan blade breaking in flight, ripping through the engine and sending debris into the wing and through a cabin window, CBS News transportation correspondent Kris Van Cleave reports.

"A piece of the engine's cover was ripped off, coming down 75 miles from the Philadelphia Airport," said NTSB chair and former 737 pilot Robert Sumwalt.

Southwest says the 18-year-old Boeing 737 was inspected just three days before the accident. The NTSB will review its maintenance history.

Southwest flies more than 700 737's with an average age of just under 11 years, but it is not uncommon for airliners to fly for 20 years or more.

Passengers are calling Captain Tammie Jo Shults a hero for safely landing the plane. Shults, who one passenger said had nerves of steel, was one of the first women to become a Navy fighter pilot.

When the window burst, 43-year-old Jennifer Riordan, a married mother of two from New Mexico, was partially sucked out of the plane. Fellow passengers pulled her back in and unsuccessfully attempted CPR.

She is the first passenger on a U.S. airliner to die in an accident since 2009.

"Jennifer wanted to put things into action, said friend Rachel Russo. "She really wanted to show how she could make a difference."

The NTSB will compare this incident with a 2016 Southwest engine failure under similar circumstances. At least one member of Congress is now calling hearings on aviation safety.