CFM International, a joint venture between General Electric Aerospace and Safran Aircraft Engines (formerly Snecma), has established itself as the world's largest commercial aircraft engine manufacturer. Founded in 1974 and based in Cincinnati, Ohio, the company holds nearly 40% of the global market share and has delivered over 37,500 engines to more than 570 operators worldwide.
The CFM56 is recognized as the most produced commercial jet engine ever built. Its origins trace back to the 1960s when Snecma began developing the M56 engine but lacked experience with high-pressure turbines. This led to a partnership with General Electric, which resulted in the formation of CFM International in 1974. The development responsibilities were divided: GE handled the high-pressure compressor, combustor, and high-pressure turbine, while Snecma managed the fan, low-pressure compressor and turbine, and airframe integration.
The first test run of a CFM56 engine occurred in June 1974. By February 1977, it was flight-tested on a McDonnell Douglas YC-15 and later on a Sud Aviation Caravelle at Snecma's facility in France. Although initially developed for military applications like the US Air Force’s Advanced Medium STOL Transport competition, CFM International shifted focus toward re-engining contracts for aircraft such as the Douglas DC-8, Boeing 707, and KC-135 Stratotanker. Securing Boeing's KC-135 contract proved pivotal for the program.