Southwest engine explodes Passenger partially Ejected through window (2018 CVR + )

Southwest Airlines Flight 1380 left LaGuardia Airport just after 10:30 a.m. on 17 April 2018, climbing toward cruise altitude on its way to Dallas. About twenty minutes in, still climbing through roughly 32,000 feet, a fan blade in the left CFM56 engine broke off at its root, a failure the NTSB later attributed to metal fatigue that ordinary visual inspection would not have caught. The detached blade tore the engine's inlet and cowling apart. Fragments from the cowling struck the wing, the fuselage, and the horizontal stabilizer, and one piece punched a hole beside a cabin window.

The Fan Blade Failure

The window failed and the cabin depressurized instantly. Passenger Jennifer Riordan, a 43-year-old bank executive from Albuquerque seated beside the window, was partially pulled through the opening by the outrushing air. Fellow passengers, including off-duty firefighter Andrew Needum, fought to pull her back inside the cabin against winds the NTSB later estimated at several hundred miles per hour. Seven other passengers suffered minor injuries in the confusion that followed.

In the cockpit, Captain Tammie Jo Shults, a former U.S. Navy fighter pilot, and First Officer Darren Ellisor worked to stabilize a badly damaged aircraft while radioing air traffic control in a voice witnesses and investigators later described as strikingly calm given the circumstances. Shults requested a diversion to Philadelphia, the nearest suitable airport, and the crew brought the aircraft down safely roughly 20 minutes after the engine failed, executing an emergency landing with a partially depressurized cabin and a wounded passenger onboard.

Riordan died of her injuries after being brought back inside the aircraft, becoming the first fatality on a U.S. commercial airline flight since 2009. The NTSB's investigation, filed under case number DCA18MA142, traced the failure to a fatigue crack in the fan blade that had not been detectable through the visual inspection standards in place at the time. In the aftermath, the FAA mandated more rigorous ultrasonic inspection of CFM56 fan blades industry-wide, closing a gap between what regulators had required and what the engine's failure modes actually demanded.

The accident sequence did not end with the engine stopping. The fan-blade separation damaged the inlet and fan-cowl structure, and pieces of that structure struck multiple parts of the aircraft. The NTSB investigation later documented that fan blade No. 13 fractured at the root and that the fracture surface contained features consistent with low-cycle fatigue.

The investigation also established why the failure was difficult to detect before the accident. The crack originated in the blades dovetail area and was not readily detectable by the inspection methods being used at the relevant stages of the components service life. The later safety response included more sensitive inspection methods for CFM56 fan blades.

The cabin consequences were separate from the initial engine failure but directly connected to the debris path. A fan-cowl component struck the fuselage near a cabin window, the window departed, and the rapid depressurization created the fatal injury mechanism. The crew then had to manage an aircraft with significant structural and aerodynamic damage while diverting to Philadelphia.

On April 17, 2018, about 1103 eastern daylight time, Southwest Airlines flight 1380, a Boeing 737-7H4, N772SW, experienced a left engine failure while climbing through flight level 320 en route to the flights assigned cruise altitude.

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