METHOD AND DEVICE FOR ENTERING AND EXITING AN ECONOMICAL OPERATING MODE FOR A TWIN-ENGINE AIRCRAFT

The present invention relates to a method of controlling an economical operating mode for an aircraft (1) comprising two heat engines (11), only one of said heat engines (11) being active and supplying mechanical power to said rotor (2,3) in said economical operating mode. Operating parameters of said aircraft (1) are measured and then compared with functional and safety limitations relating to said economical operating mode. When said aircraft (1) is in said economical operating mode, if a functional limitation is not complied with by one of said parameters, an alert of proximity to said functional limitations is issued to inform the pilot, and if one of said safety limitations is not complied with, said economical operating mode is disengaged, each heat engine (11) not supplying mechanical power to said at least one rotor (2,3) being started.