Avoid clearances that require small aircraft or helicopters to taxi in proximity to taxiing or ___ helicopters.

• A. parked
• B. air taxiing
• C. running
• D. hover-taxiing

Answer: (D)

The concept tested is how rotorcraft movement near the ground creates unique hazards that affect other aircraft. A helicopter that is hover-taxiing is in a controlled hover close to the surface while moving laterally or forward to reposition itself. In this state, rotor downwash and vortices are strong and variable, making nearby aircraft susceptible to unexpected rolling, yaw, or loss of control, and also kicking up debris. Because of that increased risk, clearances are written to avoid requiring small airplanes or helicopters to taxi in proximity to helicopters that are in a hover-taxiing state.

The other options describe states that don’t involve the same hovering-repositioning condition. Parked helicopters are stationary, and terms like air taxiing or running don’t capture the same hovering-based hazard. Hover-taxiing is the precise condition that creates the necessity for increased separation, so it’s the best fit.