How must non-self-propelled equipment be marked for safety on an airport apron?

Non-self-propelled equipment must be marked with reflectors evenly spaced on the sides and back for safety on an airport apron. This marking method is critical as it enhances visibility, especially in low-light conditions or poor weather. Having reflectors allows other airport operators, pilots, and staff to see such equipment from a distance, reducing the risk of accidents or collisions on the busy apron where a variety of vehicles and aircraft operate.

Properly spaced reflectors ensure that the equipment can be recognized from different angles, providing a clear indication of its presence and location. This is particularly important since non-self-propelled equipment could be at rest or moving slowly, and other vehicles or aircraft need to be alerted to their location promptly.

While other options might include measures for visibility or safety, they do not provide the same level of assurance and comprehensive coverage that evenly spaced reflectors do. Bright colors alone may not be as effective in low visibility, and warning signs or reflective material limited to the wheels do not provide the same level of awareness as full side and back marking.