What is the elevation of a horizontal surface above the runway?

The elevation of a horizontal surface above the runway is a specific measurement that pertains to the vertical distance between the surface in question and the runway itself. The correct choice indicates that this elevation is set at 150 feet, which is a common standard in various aviation and airport design criteria.

Typically, horizontal surfaces are established to ensure that there is adequate clearance for aircraft operations and to maintain safety standards. In airport operations and design, these elevations are carefully calculated to prevent any obstructions that could interfere with aircraft taking off or landing, especially during low flight phases.

The other options represent elevations that may not conform to typical regulations and standards commonly used in aviation. Each elevation would have implications for operational safety and regulatory compliance, making 150 feet a practical and realistic choice among typical runway elevations. Understanding these measurements is crucial for proper airport design and ensuring the safety of aircraft operations.