What is the minimum clear zone diameter required for a helicopter landing zone?

The minimum clear zone diameter required for a helicopter landing zone is critical for ensuring the safety of the landing and takeoff process. A clear zone of 100 feet (30 meters) allows for sufficient space free from obstacles for both the helicopter and any personnel involved. This space is necessary to accommodate the rotor wash and to prevent any potential hazards that could arise from nearby structures or equipment during the helicopter's approach and departure.

Having a 100-foot diameter allows enough buffer zone to minimize risks associated with helicopter operations, such as debris, loose objects, and uneven terrain. It also ensures that emergency personnel have adequate space to maneuver safely around the aircraft once it has landed. The specified diameter is consistent with safety guidelines and recognized standards that prioritize the well-being of both the helicopter crew and any individuals that may be in proximity to the landing area.

While other options provide various dimensions, they do not meet the established requirements for safety and operational effectiveness in helicopter landings. A smaller clear zone could potentially lead to dangerous situations, thus emphasizing the importance of adhering to the 100-foot guideline.