What is rotor arc and why must ground personnel avoid it?

• A. The circular path of the rotor blades; approaching within it risks blade strike and injury.
• B. A fixed radius around the helicopter used for approach distance markers.
• C. The zone above the rotor where blade tips create gusts only at takeoff.
• D. The area directly under the rotor hub that is harmless during hover.

Answer: (A)

The rotor arc is the circular path swept by the rotor blades as they rotate. This moving circle defines the dangerous zone around the helicopter. Ground personnel must stay out of it because any blade—at any height or pitch—can strike a person or object if they are within that path. A blade strike can cause severe injury or death and can occur even when the helicopter is not moving fast or when you think you’re clear. Conditions like rotor speed changes, startup, shutdown, or adjustments to blade pitch can bring blades into contact with anything inside the arc, so the safe practice is to never step into that circular area around the rotor.