Investigators found a major clue to what may have caused Southwest jet's engine failure

  • NTSB chairman Robert Sumwalt said the failed engine on the Southwest Airlines jet is missing a fan blade.
  • Investigators found evidence of metal fatigue at the point where the blade broke off.
  • 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. To be specific, it's the 13th of 24 blades. 

According to Sumwalt, a preliminary examination of where the blade failed found evidence of metal fatigue. The entire investigation is expected to take 12-15 months. 

However, Sumwalt told the media Southwest Airlines CEO Gary Kelly indicated the airline will immediately begin enhanced inspections of the engines across its entire fleet more than 710 Boeing 737s using ultrasonics. 

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Southwest plane makes emergency landing in Philly after engine incident
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Southwest plane makes emergency landing in Philly after engine incident

A Southwest Airlines flight heading from New York's LaGuardia Airport to Dallas was forced to make an emergency landing at Philadelphia International Airport on Tuesday after experiencing engine issues.

Photo: Facebook/Marty Martinez

Marty Martinez, a passenger on Flight 1380, took to social media after the incident to share photos of the severe damage sustained by the aircraft, which included a damaged left engine and one blown-out window. 

Photo: Facebook/Marty Martinez

A photo of the plane's damaged engine.

Photo: Facebook/Marty Martinez

Photo: Facebook/Marty Martinez
Photo: Facebook/Marty Martinez
Photo: Facebook/Marty Martinez
Photo: Facebook/Marty Martinez
Photo: Facebook/Marty Martinez
Photo: Facebook/Marty Martinez
Photo: Facebook/Marty Martinez
Photo: Facebook/Marty Martinez
Emergency personnel monitor the damaged engine of Southwest Airlines Flight 1380, which diverted to the Philadelphia International Airport this morning after the airline crew reported damage to one of the aircraft's engines, on a runway in Philadelphia, Pennsylvania U.S. April 17, 2018. REUTERS/Mark Makela
Emergency personnel monitor the damaged engine of Southwest Airlines Flight 1380, which diverted to the Philadelphia International Airport this morning after the airline crew reported damage to one of the aircraft's engines, on a runway in Philadelphia, Pennsylvania U.S. April 17, 2018. REUTERS/Mark Makela
Emergency personnel monitor the damaged engine of Southwest Airlines Flight 1380, which diverted to the Philadelphia International Airport this morning after the airline crew reported damage to one of the aircraft's engines, on a runway in Philadelphia, Pennsylvania U.S. April 17, 2018. REUTERS/Mark Makela
Emergency personnel monitor the damaged engine of Southwest Airlines Flight 1380 which diverted to the Philadelphia International Airport this morning after the airline crew reported damage to one of the aircraft's engines, on a runway in Philadelphia, Pennsylvania U.S. April 17, 2018. REUTERS/Mark Makela
Emergency personnel monitor the damaged engine of Southwest Airlines Flight 1380, which diverted to the Philadelphia International Airport this morning after the airline crew reported damage to one of the aircraft's engines, on a runway in Philadelphia, Pennsylvania U.S. April 17, 2018. REUTERS/Mark Makela TPX IMAGES OF THE DAY
A U.S. NTSB investigator is on scene examining damage to the engine of the Southwest Airlines plane in this image released from Philadelphia, Pennsylvania, U.S., April 17, 2018. NTSB/Handout via REUTERS ATTENTION EDITORS - THIS IMAGE HAS BEEN SUPPLIED BY A THIRD PARTY.
U.S. NTSB investigators are on scene examining damage to the engine of the Southwest Airlines plane in this image released from Philadelphia, Pennsylvania, U.S., April 17, 2018. NTSB/Handout via REUTERS ATTENTION EDITORS - THIS IMAGE HAS BEEN SUPPLIED BY A THIRD PARTY.
U.S. NTSB investigators are on scene examining damage to the engine of the Southwest Airlines plane in this image released from Philadelphia, Pennsylvania, U.S., April 17, 2018. NTSB/Handout via REUTERS ATTENTION EDITORS - THIS IMAGE HAS BEEN SUPPLIED BY A THIRD PARTY.
U.S. NTSB investigators are on scene examining damage to the engine of the Southwest Airlines plane in this image released from Philadelphia, Pennsylvania, U.S., April 17, 2018. NTSB/Handout via REUTERS ATTENTION EDITORS - THIS IMAGE HAS BEEN SUPPLIED BY A THIRD PARTY. TPX IMAGES OF THE DAY
U.S. NTSB photo shows parts of the engine cowling from the Southwest Airlines plane which blew its engine in mid air yesterday over the skies of Philadelphia, Pennsylvania, U.S., in this image released on April 18, 2018. NTSB/Handout via REUTERS ATTENTION EDITORS - THIS IMAGE HAS BEEN SUPPLIED BY A THIRD PARTY.
U.S. NTSB photo shows a part of the engine cowling from the Southwest Airlines plane which blew its engine in mid air yesterday over the skies of Philadelphia, Pennsylvania, U.S., in this image released on April 18, 2018. NTSB/Handout via REUTERS ATTENTION EDITORS - THIS IMAGE HAS BEEN SUPPLIED BY A THIRD PARTY.
@SouthwestAir These are the hero’s of SWA 1380 NYC to Dallas We lost an engine mid-flight and they guided back to P… https://t.co/0fsymQo9lU
@SouthwestAir I want to thank the crew of SWA 1380 for a great job getting us to the ground safely after losing in… https://t.co/C03wL1SYtJ
U.S. Navy Lieutenant Tammie Jo Shults, who is currently a Southwest Airlines pilot, poses in front of a Navy F/A-18A in this 1992 photo released in Washington, DC, U.S., April 18, 2018. Thomas P. Milne/U.S. Navy/Handout via REUTERS ATTENTION EDITORS - THIS IMAGE WAS PROVIDED BY A THIRD PARTY.
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The Boeing 737-700 involved in the incident was delivered new to Southwest Airlines in July 2000. The 17.8-year-old jet is powered by a pair of CFM International CFM56-7B turbofan engines. CFM International is a joint venture between GE Aviation and France's Safran Aircraft Engines. 

The CFM56-7B is one of the most popular jet engines in the world and can be found on more than 6,700 aircraft around the world. 

"The members of the CFM Team worldwide wish to express their deepest condolences to the family of the victim of this incident," the jet engine maker said in a statement. "CFM will support the NTSB and Southwest Airlines in determining the cause of the accident and CFM and its parent companies, GE and Safran, will make every resource necessary available to ensure support."

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