Define a helicopter landing zone (HLZ).

A helicopter landing zone (HLZ) is specifically defined as a designated area for loading and unloading troops and supplies from helicopters. This area is crucial in military operations, allowing for the efficient and effective transport of personnel and equipment. The HLZ is carefully selected based on various factors including safety, accessibility, and operational requirements.

In operational contexts, the HLZ must be appropriately marked and secure to facilitate swift operations while minimizing risks to both the aircraft and the personnel involved. Proper planning and coordination are essential to ensure that the HLZ can accommodate the type of helicopter being used and that it is clear of any obstacles that could impede landing or takeoff.

While the other options present various types of areas related to aircraft and operations, they do not accurately capture the primary function of a helicopter landing zone. The HLZ is solely focused on the logistics of troop and supply movements, distinguishing it from maintenance areas, air traffic control zones, and exclusive medical evacuation sites.