Does the outer horizontal surface have a slope?

Does the outer horizontal surface have a slope?

• A. Yes
• B. No
• C. It varies
• D. Only in portions

Answer: (B)

The outer horizontal surface is defined as a level plane extending outward from the primary surface at a constant elevation, parallel to the ground. Because it runs flat, its slope is zero across its extent. This flat boundary provides a uniform obstacle clearance plane around the airport. Other surfaces are designed with slopes to protect inbound flight paths, but the outer horizontal surface itself remains level. So, it does not have a slope.

The outer horizontal surface is defined as a level plane extending outward from the primary surface at a constant elevation, parallel to the ground. Because it runs flat, its slope is zero across its extent. This flat boundary provides a uniform obstacle clearance plane around the airport. Other surfaces are designed with slopes to protect inbound flight paths, but the outer horizontal surface itself remains level. So, it does not have a slope.