Southwest Airlines Flight 3472
N766SW, the aircraft involved, photographed in March 2012
|Date||27 August 2016|
|Summary||Uncontained engine failure|
|Site||Over the Gulf of Mexico|
|Aircraft type||Boeing 737-7H4 (WL)|
|IATA flight No.||WN3472|
|ICAO flight No.||SWA3472|
|Call sign||SOUTHWEST 3472|
|Flight origin||Louis Armstrong New Orleans International Airport|
|Destination||Orlando International Airport|
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 27 August 2016, the Boeing 737-7H4 (WL), 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.
The aircraft involved was a 16-year-old Boeing 737-7H4 (WL) (registration number N766SW), delivered to Southwest in May 2000. The jet was subsequently returned to service and as of May 2019[update] is still flying for Southwest.
Initial findings from the examination of the airplane include:
- The left engine inlet separated from the engine during the flight. Debris from the engine inlet damaged the airplane fuselage, wing and empennage.
- A 5-inch by 16-inch hole was found in the left fuselage just above the left wing.
- No fan blade or inlet material was found in the hole and the passenger interior compartment was not penetrated.
- During the accident sequence, the airplane experienced a cabin de-pressurization.
- The aircraft maintenance records are being reviewed.
Initial findings from the engine examination include:
- One fan blade separated from the fan disk during the accident flight.
- The root of the separated fan blade remained in the fan hub; however, the remainder of the blade was not recovered.
Initial findings from the metallurgical examination conducted in the NTSB Materials Laboratory include:
- The fracture surface of the missing blade showed curving crack arrest lines consistent with fatigue crack growth. The fatigue crack region was 1.14-inches long and 0.217-inch deep.
- The center of the fatigue origin area was about 2.1 inches aft of the forward face of the blade root. No surface or material anomalies were noted during an examination of the fatigue crack origin using scanning electron microscopy and energy-dispersive x-ray spectroscopy.
- The blades are manufactured of a titanium alloy and the root contact face is coated with a copper-nickel-indium alloy.
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 (US) and Safran Aircraft Engines (France). 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.
- Southwest Airlines Flight 1380, a 2018 accident involving the same airline with an engine failure with a similar aircraft and engine causing one fatality.
- "NTSB Identification: DCA16FA217". ntsb.gov. Retrieved April 5, 2017.
- "N766SW Southwest Airlines Boeing 737-700 - cn 29806 / 537". Planespotters.net. Retrieved April 5, 2017.
- "FAA Registry - Aircraft - N-Number Inquiry". registry.faa.gov. Archived from the original on 2019-05-03. Retrieved 2019-05-03.
- "Investigative Update Provides Initial Findings in Investigation of Uncontained Engine Failure". ntsb.gov. Retrieved April 5, 2017. This article incorporates text from this source, which is in the public domain.