What is the primary purpose of the Trim Aid Device (TAD)?

The primary purpose of the Trim Aid Device (TAD) is to maintain directional trim. This device is essential in ensuring that an aircraft flies straight and level without requiring constant control inputs from the pilot. By automatically adjusting the control surfaces to counteract unwanted yaw or roll, the TAD helps achieve and sustain the desired flight path. This is particularly important in maintaining stability and ease of handling, reducing pilot workload during flight.

Fuel efficiency, airspeed control, and mechanical safety are important considerations in aviation, but they are not the primary functions of the TAD. Instead, the TAD focuses on aiding the pilot in managing the aircraft's trim, thus enhancing overall flight performance and safety.