The invention relates to an overspeed protection device of an aircraft engine

The invention relates to a method for detecting a malfunction in a first turboshaft engine, referred to as an inoperative engine (4), of a twin-engine helicopter, and for controlling a second turboshaft engine, referred to as a healthy engine (5), each engine (4, 5) comprising protective stops regulated by a regulation device which define a maximum power regime, characterised in that it comprises: a step (10) of detecting an indication of failure of said inoperative engine (4); a step (11) of modifying said protective stops of said healthy engine (5) into protective stops which correspond to a maximum power single-engine regime, in the case of the detected indication of failure; a step (12) of confirming a failure of said inoperative engine (4); a step (13) of controlling an increase in the flow rate of fuel supply of said healthy engine (5), in the event of a confirmed failure.

A system and method of detecting an uncontrolled high thrust (UHT) condition in a turbofan gas turbine engine includes processing data to determine when a current commanded fan speed value is greater than a predetermined speed value. A current UHT commanded fan speed value is processed to determine if it will cause a target fan speed value to increase, remain steady, or decrease. The target fan speed value is set equal to the current UHT commanded fan speed value when the current UHT commanded fan speed value will cause the target fan speed value to increase or remain steady, and to a deceleration threshold value when the current UHT commanded fan speed value will cause the target fan speed value to decrease. An uncontrolled high thrust alert signal is generated when actual engine fan speed exceeds the target fan speed value by a predetermined amount for a preset time period.

A blocking device for preventing an inappropriate shut-off of an engine of an aircraft. The blocking device enables by default the actuation of the shut-off unit and receives information representative of an activated or inactivated state of a fuel shut-off lever, of a reduced or non-reduced speed state of a throttle lever, and a correct or incorrect operating state of the engine. The blocking device blocks the actuation of the shut-off unit when the throttle lever is in an inactivated state, when the engine is in a correct operating state, and when, in addition, the throttle lever is in a non-reduced speed state or the throttle lever is in a reduced speed state and, in addition, the opposite propulsion engine is in a failed state or in an incorrect operating state.