CFM International CFM56

The CFM International CFM56 (U.S. military designation F108) series is a family of high-bypass turbofan aircraft engines made by CFM International (CFMI), with a thrust range of 18,000 to 34,000 pounds-force (80 to 150 kilonewtons). CFMI is a 50–50 joint-owned company of SNECMA, France and GE Aviation (GE), USA. Both companies are responsible for producing components and each has its own final assembly line. GE produces the high-pressure compressor, combustor, and high-pressure turbine, and SNECMA manufactures the fan, gearbox, exhaust and the low-pressure turbine, while some components are made by Avio of Italy. The engines are assembled by GE in Evendale, Ohio, and by SNECMA in Villaroche, France. The completed engines are marketed by CFMI.

The CFM56 first ran in 1974 and, despite initial political problems, is now one of the most common turbofan aircraft engines in the world, with more than 20,000 having been built in four major variants. It is most widely used on the Boeing 737 airliner and, under military designation F108, replaced the Pratt & Whitney JT3D engines on many KC-135 Stratotankers in the 1980s, creating the KC-135R variant of this aircraft. It is also the only engine (CFM56-5C) used to power the Airbus A340-200 and 300 series. The engine (CFM56-5A and 5B) is also fitted to Airbus A320 series aircraft.

Several fan blade failure incidents were experienced during the CFM56's early service, including one failure that was noted as a cause of the Kegworth air disaster, while some variants of the engine experienced problems caused by flight through rain and hail. However, both these issues were resolved with engine modifications. By January 2010, the CFM56 had flown more than 470 million cumulative hours (the equivalent of more than 53,000 years).