An electromechanical actuator, having a plurality of modes, comprising: an electrical motor having a motor shaft extending along an axis of the electromechanical actuator, the motor driving the shaft to rotate about the axis; a gear assembly mounted around, and in geared connection with the shaft, to rotate with the shaft; an electromechanical actuator output connected to the gear assembly such that rotation of the motor shaft causes rotation of the output via the gear assembly, the output rotating at a speed which is a predetermined fraction of the speed of rotation of the motor shaft based on the gear ratio of the gear assembly; a synchroniser comprising a first portion connected to an end of the motor shaft, and a second conical portion, wherein the synchroniser has an engaged position in which rotation of the first portion is transmitted to the second conical portion, and a disengaged position wherein the second conical portion is axially spaced apart from the first portion, along the axis, such that rotation of the first portion is not transmitted to the second conical portion; a solenoid connected to the second conical portion, the solenoid configured to pull the second conical portion along the axis away from the first portion when the solenoid is energised wherein, in an active mode of the plurality of modes, the solenoid is energised and wherein rotation of the motor shaft in either direction of rotation drives the output to rotate; wherein in an anti-extension mode, the solenoid is not energised, characterized in that the first portion is a conical portion; the second conical portion is connected to a ratchet; wherein in the anti-extension mode the output shaft is connected for rotation, via the synchroniser, to the ratchet; and a cam feature arranged to rotate with the output, the cam feature having a cam profile such that when the output is in positive stroke and the solenoid is de-energised, the ratchet is engaged, wherein the ratchet is arranged to prevent rotation of the output in a predetermined direction of rotation; and when the output is in negative stroke, the ratchet is disengage so as to allow rotation of the output in either direction of rotation. an electrical motor having a motor shaft extending along an axis of the electromechanical actuator, the motor driving the shaft to rotate about the axis; a gear assembly mounted around, and in geared connection with the shaft, to rotate with the shaft; an electromechanical actuator output connected to the gear assembly such that rotation of the motor shaft causes rotation of the output via the gear assembly, the output rotating at a speed which is a predetermined fraction of the speed of rotation of the motor shaft based on the gear ratio of the gear assembly; a synchroniser comprising a first portion connected to an end of the motor shaft, and a second conical portion, wherein the synchroniser has an engaged position in which rotation of the first portion is transmitted to the second conical portion, and a disengaged position wherein the second conical portion is axially spaced apart from the first portion, along the axis, such that rotation of the first portion is not transmitted to the second conical portion; a solenoid connected to the second conical portion, the solenoid configured to pull the second conical portion along the axis away from the first portion when the solenoid is energised wherein, in an active mode of the plurality of modes, the solenoid is energised and wherein rotation of the motor shaft in either direction of rotation drives the output to rotate; wherein in an anti-extension mode, the solenoid is not energised, characterized in that the first portion is a conical portion; the second conical portion is connected to a ratchet; wherein in the anti-extension mode the output shaft is connected for rotation, via the synchroniser, to the ratchet; and a cam feature arranged to rotate with the output, the cam feature having a cam profile such that when the output is in positive stroke and the solenoid is de-energised, the ratchet is engaged, wherein the ratchet is arranged to prevent rotation of the output in a predetermined direction of rotation; and when the output is in negative stroke, the ratchet is disengage so as to allow rotation of the output in either direction of rotation.