What is rotor wash and why is it a hazard on the ground?

• A. The powerful downward airflow from the rotor that can blow debris and injure personnel or damage equipment
• B. A clean air stream that enhances visibility for ground troops
• C. A type of wind shear that affects rotor speed
• D. The noise produced by the helicopter rotor to communicate with ground crew

Answer: (A)

Rotor wash is the strong downward airflow produced by the helicopter’s rotor as it generates lift. That downwash shoots air straight down and fans out across the ground, capable of picking up and moving loose debris, tools, and equipment. Because of this, anyone or anything in the rotor path can be struck, knocked over, or pushed into hazards, and dust or debris can cloud visibility or irritate eyes and lungs. This makes ground operations around a hovering or landing helicopter risky if people or gear are not kept well clear of the rotor arc. It’s not simply a clean air stream, it isn’t wind shear, and it isn’t about the noise produced; the hazard comes from the powerful downward push of air and the debris it can carry.