Failsafe electro-mechanical actuator

A failsafe electro-mechanical actuator for moving a component within an aircraft, the actuator comprising:

• an output shaft having a first end and a second end spaced apart from each other along a shaft axis, wherein the second end couples with the component, and outwardly facing helical grooves formed along the first end;
• and
• a motor shaft surrounding the output shaft;
• a harmonic drive between the motor shaft and the output shaft that transfers motion from the motor shaft to the output shaft in a first mode of operation;
• ball bearings seated at the first end of the motor shaft such that the ball bearings project inwardly from the motor shaft;
• wherein,
• in the first mode of operation:
• the ball bearings are disengaged from the output shaft so that the output shaft rotates with the motor shaft, and
• in a second mode of operation, the motor shaft axially moves toward the first end of the output shaft;
• the motor shaft is rotationally fixed;
• and the ball bearings engage the helical grooves in the output shaft, whereby the output shaft rotates.