Which rule states that aircraft must maintain an altitude of 500 feet above the surface?

The altitude requirement of maintaining 500 feet above the surface is specifically addressed in regulations governing the operation of aircraft in the vicinity of populated areas or structures. This requirement is designed to ensure safety during flight operations, minimizing the risk of accidents involving people, property, and structures on the ground.

The rule emphasizes that aircraft must not fly below this altitude except for takeoffs, landings, or when conducting specific maneuvers that require lower altitude operations under defined circumstances. This guideline is in place to enhance safety and environmental considerations in aviation.

The other options, though they may sound plausible, do not specifically denote the regulation pertaining to the 500 feet above surface requirement, making the chosen answer the most accurate and contextually relevant.