Abstract: A method of managing an engine failure on a rotary wing aircraft (1) having a hybrid power plant (5) with at least two fuel-burning engines (13, 13?), at least one electric machine (12), and a main gearbox (11). Said aircraft (1) also has electrical energy storage means (14) and a main rotor (2) mechanically connected to said hybrid power plant (5). In said method, during each flight, the operation of said engines (13, 13?) is monitored in order to detect a failure of any one of them, and then once a failure of one of said engines (13, 13?) has been detected, said electric machine (12) is controlled, if necessary, to deliver auxiliary power We in order to avoid a deficit appearing in the total power WT of said hybrid power plant (5), thereby enabling the pilot of said aircraft (1) to fly said aircraft (1) safely without degrading said hybrid power plant (5).

Abstract: A method of managing an engine failure on a rotary wing aircraft (1) having a hybrid power plant (5) with at least two fuel-burning engines (13, 13?), at least one electric machine (12), and a main gearbox (11). Said aircraft (1) also has electrical energy storage means (14) and a main rotor (2) mechanically connected to said hybrid power plant (5). In said method, during each flight, the operation of said engines (13, 13?) is monitored in order to detect a failure of any one of them, and then once a failure of one of said engines (13, 13?) has been detected, said electric machine (12) is controlled, if necessary, to deliver auxiliary power We in order to avoid a deficit appearing in the total power WT of said hybrid power plant (5), thereby enabling the pilot of said aircraft (1) to fly said aircraft (1) safely without degrading said hybrid power plant (5).