Advanced emergency collective actuator with friction pull-off and method for a helicopter

A method for use with a helicopter including a rotor system having a main rotor with an adjustable pitch that is controlled at least in part by a pilot using a collective control and the collective control pivotally supports a friction control lever as part of a friction control that is engageable by the pilot to selectively increase a control force that is required as a minimum to move the collective control, said method comprising:

• responsive to an indication of a low rotor RPM of the main rotor, initially applying an actuator force to the friction control lever to move the friction control lever from an engaged position to a disengaged position;
• and
• after the friction control lever reaches the disengaged position, continuing to apply the actuator force to the friction control lever to move the collective control, having the friction control lever pivotally supported thereon, toward a minimum collective pitch position.

For use with a helicopter including a rotor system having a main rotor with an adjustable pitch that is controlled at least in part by a pilot using a collective control and the collective control pivotally supporting a friction lever that can be engaged by the pilot to selectively increase a control force that is required as a minimum to move the collective control, an apparatus comprising:

• an actuator arrangement including a motor having an output shaft for rotation to change the adjustable pitch by exerting an actuation force and a clutch supported by the output shaft and in operative communication with the collective control such that the clutch slips relative to the output shaft (i) to allow the pilot to overcome said actuation force using the collective control and (ii) responsive to an engagement of the friction lever by the pilot, but otherwise the clutch co-rotates with the motor shaft to bias the adjustable pitch toward a minimum collective pitch position;
• and
• a control arrangement that is configured to receive a signal that is indicative of a low rotor RPM condition and to respond to said signal by activating the actuator arrangement to exert the actuation force.