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 main idea here is safety around rotorcraft during ground movements. A helicopter that is hover-taxiing is actively moving while still producing lift, using rotor downwash to slide a short distance above the surface. That combination creates unpredictable movement and strong rotor wash, which can affect nearby aircraft or ground personnel and equipment. If a controller issues a clearance that would have a small aircraft taxiing close to such a helicopter, there’s a real risk of rotor wash blowing debris or causing the other aircraft to drift into the rotor area. Because of that, clearances are kept away from situations where a small plane would be required to taxi near a helicopter that is in hover or transitioning through hover-taxiing. The other states described (being parked, simply on the ground taxiing in a conventional way, or running) do not carry the same level of unpredictable rotor-induced motion, so they don’t require the same heightened separation.