An engine on Southwest Airlines' Flight 1380 exploded midair on Tuesday, killing one passenger and injuring a second.
The Boeing 737-700, en route from New York to Dallas with 149 people on board, successfully made an emergency landing in Philadelphia.
Less than an hour after takeoff, the plane's left engine exploded, sending shrapnel flying and shattering a window. The ensuing rapid cabin depressurization nearly pulled a passenger through the window, and fellow passengers worked to hold her in the plane.
Later, passenger Jennifer Riordan, 43, died, making her the first to die in a US commercial aviation accident in 9 years.
Initial investigations show that an engine fan blade was missing, as well as metal fatigue where it should have been attached. The blade is believed to have broken off, National Transportation Safety Board (NTSB) Chairman Robert Sumwalt told a press conference.
Noting that part of the engine's covering had been found near the airport, Sumalt said the flight's data recorder and cockpit voice recorder had been sent to Washington. The plane was about 20 minutes into the flight, flying at 32,500 feet, when the engine failed.
Southwest Airlines expressed condolences and sympathy, and confirmed that the plane had been inspected on Saturday, and that Riordan's death was the airline's firest in 51 years of operations. The company also said it would conduct ultrasonic inspections of fan blades on the CFM56 engines on all of its 737s.
It is not clear if Riordan is the woman who was nearly sucked out of the window.