Active trim system of a flight control system of an aircraft

An active trim system of a flight control system of an aircraft comprising:

• a manual control member configured to operate the flight control system and transmitting the tactile feeling to the pilot;
• an intermediate linkage member mechanically linked to the linkage connection on the manual control member;
• a spring with a longitudinal axis and connected to the intermediate linkage member and to a structure in the aircraft,
• a reversible actuator including a rod connected in series with a motor forming a rod and motor assembly, wherein one end of the rod and motor assembly is connected to the intermediate linkage member and an opposite end is connected to the structure, the rod and motor assembly is parallel to the spring, the rod is moved back and forth by the motor in a direction of the longitudinal axis, and the reversible actuator is movable by the motor and manually by the manual control member,
• wherein the reversible actuator is configured to automatically move the intermediate linkage member to a predetermined zero position in absence of a manually applied force to the manual control member.

A method comprising:

• manually moving a flight control member to move a flight control surface of an aircraft, wherein the flight control surface is linked to an intermediate linkage member and the movement of the flight control member moves the intermediate linkage member along a first direction;
• automatically moving the flight control member to a trimmed position while the pilot is not applying manual force to the flight control member by automatically moving the intermediate linkage member by actuating a reversible actuator including a rod connected in series to a motor forming a rod and motor assembly, wherein the rod and motor assembly is connected to the intermediate linkage member and to a structure of the aircraft, and the rod is aligned along the first direction;
• applying a bias force to the intermediate linkage member by a spring connected to the intermediate linkage member and to the structure, wherein the spring is parallel to the rod and motor assembly, the bias force is aligned with the first direction, and
• deactivating the motor such that the motor does not apply force to the rod in response to a failure condition related to a trim system which includes the actuator.