The engine on a Southwest Airlines plane is inspected as it sits on the runway at the Philadelphia International Airport after it made an emergency landing in Philadelphia, Tuesday, April 17, 2018.
NTSB chairman Robert Sumwalt said the failed engine on the Southwest Airlines jet is missing a fan blade.
Southwest Airlines will immediately begin inspections of its entire fleet of more than 710 Boeing 737s.
Investigators from the National Transportation Safety Board have a major new clue in their hunt for what caused an engine on a Southwest Airlines Boeing 737 to fail mid-flight.
The incident resulted in the death of 43-year-old Jennifer Riordan of Albuquerque, New Mexico.
In a press conference Tuesday evening, NTSB chairman Robert Sumwalt announced that one of the engine's 24 fan blades had snapped off near the central hub.