Abstract: The present invention provides a device enabling the collective pitch of the blades of the main rotor of a single-engined rotorcraft to be reduced automatically in the event of an engine failure. The device comprises an actuator which increases the collective pitch of the blades above a predefined threshold, and which decreases the collective pitch below the predefined threshold. The actuator is arranged on a bell crank of the mixing unit of the rotorcraft.

Abstract: The regulating system (1) comprises in particular a metering valve (4) for metering the fuel fed to the engine (2), as a function of control commands, a device (8) for determining a pre-set value NTLcons corresponding to the pre-set value of the rotational output of the free turbine of the engine (2), and computation means (9, 10) which compute control commands making it possible to slave the output of the gas generator of the engine (2) to a pre-set value NGcons of the output of the gas generator, which depends on the rotational output NTL of the free turbine and said pre-set value NTLcons. Said device (8) comprises a means (21) for determining the position of a rudder bar of said helicopter, and an auxiliary computation means (22) which computes the pre-set value NTLcons as a function of said position of the rudder bar and of other external parameters, in particular the altitude.

Abstract: System for regulating the output of an engine of a helicopter.