The TAD maintains a takeoff trim setting until what airspeed in KIAS and no weight on wheels?

The TAD, or Trim Aid Device, is designed to assist in maintaining the appropriate trim setting for the aircraft during the critical phases of flight. The system holds the takeoff trim until the aircraft reaches an airspeed of 80 KIAS (Knots Indicated Airspeed) with no weight on the wheels. This is crucial for ensuring that the aircraft remains properly trimmed for takeoff, thereby enhancing control and stabilization.

At 80 KIAS, the aerodynamic forces acting on the aircraft become sufficient to require pilot input for further adjustments. The TAD's function is to simplify the pilot's workload during this phase by automatically adjusting the trim until that specific airspeed is reached, ensuring optimal performance and safety during takeoff. The choice of 80 KIAS is determined by safety and operational efficiency, as it provides a clear boundary for the transition from automatic to manual trim control.