Southwest Airlines Flight 3472


Southwest Airlines Flight 3472 was a regularly scheduled passenger flight operating from New Orleans International Airport in New Orleans, Louisiana to Orlando International Airport in Orlando, Florida. On August 27, 2016, the Boeing 737-7H4, with 99 passengers and five crew, 12 minutes after departure from New Orleans, was climbing through 31,000 feet and heading east over the Gulf of Mexico when the aircraft's number one CFM International CFM56-7 engine suffered an uncontained engine failure. Debris from the engine punctured the left side of the fuselage causing a loss of cabin pressure and damaged the wing and empennage. Oxygen masks were deployed to passengers while the crew initiated an emergency descent to 10,000 feet. The aircraft then diverted to Pensacola International Airport for a safe landing about 20 minutes later without further incident. While the aircraft sustained substantial damage, there were no injuries.

Aircraft

The aircraft involved was a 16-year-old Boeing 737-7H4, delivered to Southwest in May 2000. The jet was subsequently returned to service and later retired by Southwest in November 2019 to Greenwood–Leflore Airport, Mississippi.

Investigation

The accident was investigated by the Federal Aviation Administration and the National Transportation Safety Board. On September 12, 2016, the NTSB reported their initial findings.
Initial findings from the examination of the airplane include:
Initial findings from the engine examination include:
Initial findings from the metallurgical examination conducted in the NTSB Materials Laboratory include:
Future investigative work by the NTSB will include 3-D measurements of the contact areas of all the blades, a non-destructive examination of the blade surfaces for cracks, and a review of the engine maintenance records.
Parties to the investigation include the Federal Aviation Administration, Southwest Airlines, the Southwest Airlines Pilots Association, and CFM International, which is a joint venture between GE Aviation and Safran Aircraft Engines. The French Bureau of Investigation and Analysis for Civil Aviation Safety has also appointed an accredited representative who is supported by a technical advisor from Safran Aircraft Engines.
On March 30, 2020, the NTSB determined the probable cause of the accident as follows: "A low-cycle fatigue crack in the dovetail of fan blade No. 23, which resulted in the fan blade separating in flight and impacting the fan case. This impact caused the fan blade to fracture into fragments that traveled farther than expected into the inlet, which compromised the structural integrity of the inlet and led to the in-flight separation of inlet components. A portion of the inlet struck the fuselage and created a hole, causing the cabin to depressurize."