The US Federal Aviation Administration (FAA) has issued an emergency airworthiness directive (EAD) requiring airlines to inspect fan blades of some CFM56-7B engines.

Airlines must complete engine inspections within 20 days from 20 April. The order follows the engine failure of a Southwest Airlines flight powered by a CFM56-7B engine.

The incident occurred on 17 April during a flight from New York’s LaGuardia to Dallas Love Field airport, killing one passenger and injuring seven others.

FAA said in a statement: “The inspection requirement applies to CFM56-7B engines.

“Specifically, engines with more than 30,000 total cycles from new must complete inspections within 20 days.  The EAD becomes effective upon publication.

“In CFM International’s bulletin, the company recommended airlines conduct ultrasonic inspections of the fan blades of their CFM56-7B engines within 20 days.”

“The engine manufacturer estimates today’s corrective action affects 352 engines in the US and 681 engines worldwide.”

The FAA directive is based on a new service bulletin issued to CFM56-7B engine operators by manufacturer CFM International.

In CFM International’s bulletin, the company recommended airlines conduct ultrasonic inspections of the fan blades of their CFM56-7B engines within 20 days.

The inspection covers engines that have completed more than 30,000 cycles, affecting more than 680 units.

CFM has also suggested for operators to inspect engines with fan blades that will be completing 20,000 cycles by the end of August this year. This inspection is estimated to affect approximately 2,500 engines.

All other fan blades have also been recommended for inspection when they reach 20,000 cycles.

Currently, around 14,000 CFM56-7B engines are in operation with several airlines across the globe. The engine type primarily powers Boeing’s next-generation 737 aircraft.