To avoid proximity during taxiing, avoid clearances that require small aircraft or helicopters to taxi in proximity to which of the following?

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

Answer: (D)

Rotor downwash and unpredictable movement around rotorcraft during taxiing are the main hazards. A helicopter that is hover-taxiing isn’t settled on the ground; it’s hovering and maneuvering, with rotor wash that can push or pull nearby aircraft in ways that are hard to anticipate. This makes any clearance that requires another aircraft to taxi in close proximity highly risky, because a slight shift or gust could lead to a loss of control or a collision. In contrast, parked helicopters are stationary and easier to keep clear, and helicopters that are simply taxiing with rotors turning on the ground have more predictable movement. The hovering, moving helicopter scenario presents the greatest danger, so the clearance should avoid proximity to hover-taxiing helicopters.