Which statement is true regarding obstacle clearance designations?

Which statement is true regarding obstacle clearance designations?

• A. Mountainous areas require 1,000 ft clearance
• B. Non-mountainous areas require 3,000 ft clearance
• C. Mountainous areas require 2,000 ft clearance
• D. Clearance is not required in any area

Answer: (C)

Obstacle clearance designations define the vertical margin kept between a flight path and the highest obstacle in a given area to ensure safe separation from terrain. In mountainous terrain, that margin must be larger because obstacles are taller and the terrain is more variable, and winds can be stronger and more unpredictable. So the required clearance in mountainous areas is 2,000 feet. In non-mountainous areas, the margin is smaller, typically 1,000 feet, reflecting lower obstacle heights. The idea that no clearance is required is incorrect, and assigning an even larger clearance to non-mountainous areas doesn’t fit the purpose of maintaining a safe buffer from terrain.

Obstacle clearance designations define the vertical margin kept between a flight path and the highest obstacle in a given area to ensure safe separation from terrain. In mountainous terrain, that margin must be larger because obstacles are taller and the terrain is more variable, and winds can be stronger and more unpredictable. So the required clearance in mountainous areas is 2,000 feet. In non-mountainous areas, the margin is smaller, typically 1,000 feet, reflecting lower obstacle heights. The idea that no clearance is required is incorrect, and assigning an even larger clearance to non-mountainous areas doesn’t fit the purpose of maintaining a safe buffer from terrain.