Engine Type That Powered Southwest 737 Involved In Uncontained Engine Failure

The FAA will issue an Airworthiness Directive (AD) within the next two weeks that will require inspections of certain CFM56-7B engines. The directive will require an ultrasonic inspection of fan blades when they reach a certain number of takeoffs and landings. Any blades that fail the inspection will have to be replaced.

The move follows the uncontained engine failure aboard a Southwest Airlines 737-700 that resulted in the fatal injury of one of the passengers on board the airplane. NTSB Chairman Robert Sumwalt said in a news conference that the fan blades on the engine showed signs of metal fatigue in the board's initial inspection of the aircraft.

The Washington Post reports that the FAA has already issued an advisory for the engine type. The AD will make the inspections mandatory. The agency is supporting the NTSB investigation into Tuesday’s incident, and “is in communication with the manufacturers and airlines on whether any further safety steps or amendments are needed.”

A similar incident occurred on a Southwest airliner in August, 2016, damaging the aircraft, and the FAA posted an AD NPRM in the Federal REgister. Reuters reports that CFM at the time recommended a shorter time between inspections of no more than 12 months. In a comment on the NPRM, Southwest said that the time between inspections should be at least 18 months, and that only certain fan blades should be inspected.

The Washington Post reports that most airlines have already complied with the recommendation for more frequent inspections, but this most recent incident brought more urgency to the matter, prompting the issuance of an AD.

All of Southwest's 737s are powered by the CFM56 engine.

(Source: FAA news release and as cited. NTSB image)

FMI: www.faa.gov, Original report, Original Report