Initial trials and certification
On June 20, 1974, the demonstration engine for the CFM56 program ran for the first time at Evendale on a test bench belonging to General Electric. In the days that followed, and in less than ten hours of operation, it reached its full take-off thrust of 10 tonnes. In November of the same year, the CFM56 carried out its first trial on a test bench at Villaroche.
Boeing was one of the first aircraft manufacturers to realise the full potential of the CFM56 engine. Boeing president Thornton Wilson contacted Neumann and Ravaud in 1977 with a proposal for an agreement to replace the engines of the 707 using the CFM56.
On March 17, 1977, flight testing of the CFM56 began on the Caravelle flying testbench. The first flight took place at Mérignac, near Bordeaux. It lasted just over three hours and was designed to assess the performance of the engine and nacelle. In January 1979, ground and flight tests reached a total of more than 4,000 hours.
Five years after the creation of the company, and eight years after the start of the project, any contract had yet to be signed by aircraft manufacturers. The French government threatened to put the programme on hold if no commercial application was found before spring 1979. In the United States, United Airlines finally decided in March 1979 to choose the CFM56 to replace the engines of the DC-8 cargo aircraft.
On November 8, 1979, the CFM56 was certified for a nominal thrust of 24,000 lb simultaneously by the DGAC (Direction Générale de l'Aviation Civile) in France and the FAA (Federal Aviation Administration) in the United States. For the first time an engine has been certified jointly by the US agency and a European national agency. The CFM56 can now power commercial transport aircraft.
The CFM56 made its first commercial flight in April 1982 on a DC-8 Super 70 for Delta Air Lines, on a route between Atlanta and Savannah, Georgia. In February 1987, Snecma achieved its initial goal of becoming a benchmark engine manufacturer for the new European twinjet, with the maiden flight of the CFM56-5-powered A320. In 1991, the 5,000th CFM56 was delivered to Airbus Industrie. The 10,000th CFM56 was delivered at the 1999 Paris Air Show.
