Airline operators of CFM56-7B engines are aggressively responding to last Friday’s emergency airworthiness directive (EAD) from the U.S. Federal Aviation Administration (FAA) and the European Aviation Safety Agency (EASA), based on a CFM International service bulletin, which calls for inspections of fan blades on long-service engines.
Operators have completed more than 60 percent of the mandated ultrasonic inspections on CFM56-7B blades with more than 30,000 cycles since new. The inspection program, impacting about 680 CFM56-7B engines worldwide, must be completed by May 10 to comply with the FAA and EASA EADs.
The CFM56-7B engine powers the popular Boeing Next-Generation 737. Approximately 14,000 CFM56-7B engines are in operation.
CFM partners GE and Safran Aircraft Engines are supporting airlines with a team of 500 experts to complete the inspections as quickly as possible and help to minimize operational disruption.
As part of the service bulletin CFM issued on Friday, the company also recommends inspections of fan blades with more than 20,000 cycles be completed by the end of August, and inspections to all other fan blades when they reach 20,000 cycles. After first inspection, operators are recommended to repeat the inspection every 3,000 cycles, which typically represents about two years in airline service. Inspections recommended by the end of August for fan blades with 20,000 cycles will impact an additional 2,500 engines.
The airline operators and CFM are now organizing a plan to execute on the next phase of the inspection program.
A jet engine cycle comprises an engine start, takeoff and landing, and full shut down. An engine cycle is an important measurement in determining the maintenance and inspection intervals for jet engines and their components. The inspection, conducted on-wing with an ultrasonic probe along the surface of the fan blade, takes about four hours per engine.
The CFM56-7B engine first entered service on the Boeing 737 in 1997 and has long been a workhorse of the airline industry. The engine fleet has accumulated more than 350 million flight hours. About 60 customers worldwide operate engines within the cyclic thresholds of the new service bulletin.