Abstract: A method and a system for monitoring an actuator equipped with a no-back device or no-back brake, particularly an adjustable horizontal trim actuator provided in aircraft, the method including the steps of: determining a value representative of mechanical work produced by the actuator and comparing the determined value with ranges of values so as to detect a dysfunctioning of the said no-back device. If the actuator is a screw/nut type with a hydraulic motor, the value representative of the mechanical work is determined from an algebraic velocity of the motor and an algebraic differential of hydraulic pressure at terminals of the motor. A negative value corresponding to negative mechanical work then identifies a failure of the no-back device.

Abstract: The present invention relates to a method and a system for monitoring of an actuator equipped with a no-back device or no-back brake and in particular an adjustable horizontal trim actuator provided in aircraft. The method comprises the steps consisting in: determining a value representative of the mechanical work produced by the said actuator; comparing the said determined value with ranges of values so as to detect a dysfunctioning of the said no-back device. In the case of an actuator of screw/nut type and a hydraulic motor, the said value representative of the mechanical work is determined from an algebraic velocity of the motor and an algebraic differential of hydraulic pressure at the terminals of the said motor. A negative value corresponding to negative mechanical work then identifies a failure of the no-back device.