Where does the transitional surface start?

Where does the transitional surface start?

• A. The runway
• B. The horizontal surface
• C. The approach surface
• D. The primary surface

Answer: (A)

Transitional surfaces are imaginary boundaries used in airport design to protect airspace from obstructions around a runway. They rise outward and upward from the outer edge of the primary surface, which is the area that directly surrounds and includes the runway itself. Because the protective zone starts right at the boundary where the runway ends (the edge of the primary surface), the starting point of the transitional surface is essentially at the runway. This ensures that any obstacles near the pavement are kept at heights that won’t interfere with takeoffs and landings as you move away from the runway. The other surfaces—such as the horizontal surface or the approach surface—are distinct reference planes with their own purposes and do not mark the starting point of the transitional surface.

Transitional surfaces are imaginary boundaries used in airport design to protect airspace from obstructions around a runway. They rise outward and upward from the outer edge of the primary surface, which is the area that directly surrounds and includes the runway itself. Because the protective zone starts right at the boundary where the runway ends (the edge of the primary surface), the starting point of the transitional surface is essentially at the runway. This ensures that any obstacles near the pavement are kept at heights that won’t interfere with takeoffs and landings as you move away from the runway. The other surfaces—such as the horizontal surface or the approach surface—are distinct reference planes with their own purposes and do not mark the starting point of the transitional surface.