How is the Horizontal Surface defined?

How is the Horizontal Surface defined?

• A. A level plane 150 feet above the runway elevation.
• B. A slope of 7:1 rising from the runway.
• C. A curved surface conforming to terrain.
• D. A flat plane at runway elevation.

Answer: (A)

The Horizontal Surface is a fixed, level boundary used in airport design to protect airspace around the field. It is defined as a plane that sits 150 feet above the airport’s established elevation, extending horizontally outward. It doesn’t slope up from the runway, it isn’t curved to fit terrain, and it isn’t at the runway level. This constant-height plane provides a consistent check for potential obstructions near the airport, guiding safe approaches and operations.

The Horizontal Surface is a fixed, level boundary used in airport design to protect airspace around the field. It is defined as a plane that sits 150 feet above the airport’s established elevation, extending horizontally outward. It doesn’t slope up from the runway, it isn’t curved to fit terrain, and it isn’t at the runway level. This constant-height plane provides a consistent check for potential obstructions near the airport, guiding safe approaches and operations.