The minimum obstacle clearance at the departure end of runway equals:

• A. 3.3 % gradient
• B. 35 ft
• C. 0 ft
• D. 0.8 % gradient

Answer: (C)

The main idea is that obstacle clearance is handled by the required climb gradient after takeoff, not by a fixed height at the exact threshold. At the departure end of a runway, you’re starting from the surface, so there isn’t a fixed vertical clearance above the surface that must be maintained at that precise point—the minimum obstacle clearance is zero feet. The safety margin comes from achieving the specified climb gradient early in the takeoff so that you clear any obstacles as you progress along the departure path. The other options describe climb gradients or obstacle heights that are relevant to the takeoff path further along, but they do not represent the fixed minimum clearance at the departure end itself.