Where is the Primary Surface located and how far does it extend?

Where is the Primary Surface located and how far does it extend?

• A. Centered on runway edge and extends 100 feet past ends.
• B. Centered on the runway centerline and extends 200 feet past each runway end.
• C. Circles the runway with a radius of 300 feet.
• D. Follows the runway endpoint and extends 150 feet.

Answer: (B)

The primary surface is the runway-aligned protection zone defined along the runway centerline. It is centered on the runway’s centerline so the area is symmetric for both ends, and it extends 200 feet beyond each runway end to provide a buffer for takeoff and landing clearance. This arrangement ensures obstructions are evaluated within a consistent, centered strip that continues past the physical end of the runway. Descriptions that place the surface on the runway edge, imply a shorter extension, or describe a circle or a path that follows endpoints do not reflect how this surface is defined.

The primary surface is the runway-aligned protection zone defined along the runway centerline. It is centered on the runway’s centerline so the area is symmetric for both ends, and it extends 200 feet beyond each runway end to provide a buffer for takeoff and landing clearance. This arrangement ensures obstructions are evaluated within a consistent, centered strip that continues past the physical end of the runway. Descriptions that place the surface on the runway edge, imply a shorter extension, or describe a circle or a path that follows endpoints do not reflect how this surface is defined.