Tragedy struck Southwest Airlines flight 1380 on Tuesday when an engine failure prompted an emergency landing at Philadelphia International Airport. The Boeing 737 was about 40 minutes into a scheduled flight to Dallas when a sudden jolt startled passengers and crew.
“Everybody was going crazy,” passenger Marty Martinez told CNN. “I heard a loud boom, and about five seconds later, all the oxygen masks deployed.”
Shortly after the explosion, as passengers scrambled to secure oxygen and seat belts, a piece of debris thrown from the engine smashed a cabin window. A woman was partially sucked out as the aircraft depressurized, and nearby passengers rushed to pull her back into the plane.
After securing the injured woman in her seat, a nurse aboard the flight performed CPR while frightened passengers tried to plug the broken window with blankets and clothes. The harrowing ordeal left many on board badly shaken, and passengers reported the uncertainty of whether they would land safely.
“The next 20-25 minutes telling my wife and parents I loved them and what I wanted them to pass on to my unborn son,” said passenger Matt Tranchin speaking with 3AW radio Melbourne. “You don’t want to pass up the opportunity to say goodbye.”
Passengers have praised pilot Tammie Jo Shults, a former F/A-18 pilot in the U.S. Navy, for her poise in getting the aircraft safely on the ground. Her exchanges with air traffic control show exceptional composure despite the chaos unfolding on board her aircraft. “We have part of the plane missing. So we’re going to need to slow down a bit,” Shults told air traffic controllers as the crippled plane rerouted to Philly. “They said there is a hole and someone went out.”
Tragically, the passenger who was partially sucked out the window later died from her injuries. She’s been identified as a mother of two from New Mexico returning from a business trip.
As the official inquiry begins, National Transportation Safety Board (NTSB) investigators will examine the engine and review maintenance procedures to determine the cause of this tragedy. It was the first commercial passenger fatality in the U.S. since 2009, and the first in the history of Southwest Airlines.
“To my knowledge it’s the first time we have lost a window,” said Southwest CEO Gary Kelly in a press conference on Tuesday. “It’s the first fatality for the airline… I want to thank and commend our flight crew for their swift action.”
NTSB investigators are already looking at metal fatigue as a possible cause for the incident. “Our preliminary investigation of this was that there was evidence of metal fatigue where the blade separated,” said NTSB chairman Robert Sumwalt. Photos of the engine revealed a missing titanium fan blade, with signs of metal fatigue in the area of separation near the blade root.
Metal fatigue is a common culprit in engine blade separation as tensile stresses produce cracking the material. Cracks can slowly propagate over many flight cycles before a sudden failure. If metal fatigue is ultimately determined to be the cause, investigators will then work to find the origin of the fatigue cracks. Was there a flaw in the metal? A manufacturing defect? Foreign object damage? Could the accident have been prevented by better inspections or fatigue prevention applications like laser peening?
Another important question involves how debris from the engine ejected towards the aircraft. Commercial jet engines are encircled by a robust shroud of material that is designed to contain high-velocity debris in the event of an engine failure. Given the potential for ejected debris to sever fuel lines or disable flight systems, these containment shrouds are vitally important to protecting the aircraft in the event of an engine failure.
It bears pointing out that these types of incidents are very rare. We’ve written in the past about fan blade separation and other engine failures, but in most incidents the aircraft is able to land safely with its remaining engines. The difference with this incident was the ejected material piercing the fuselage, and that appears to be the cause of the tragic fatality on board SW flight 1380.
LSP Technologies sends our condolences to everyone impacted by this tragic event, and we continue our tireless efforts to fight metal fatigue in all its forms.