Which surface extends 200 ft from the runway end outward from the primary surface up to 50,000 ft?

• A. Primary surface
• B. Approach surface
• C. Transitional surface
• D. Conical surface

Answer: (B)

This question is about imaginary protection surfaces around runways. The surface that begins at the end of the primary surface and extends outward away from the runway for up to 50,000 feet is the approach surface. It’s designed to protect the instrument approach path by outlining a corridor from the runway end to distant airspace, with its horizontal extent fixed at 50,000 feet. The primary surface itself is the paved area of the runway extended 200 feet beyond each end, so it isn’t the surface reaching out to 50,000 feet. The other surfaces—transitional and conical—connect the primary surface to the larger airspace in different shapes and heights, but they don’t extend from the runway end to 50,000 feet in the same way as the approach surface. So the described surface is the approach surface.