Takeoffs are NOT permitted when which condition exists?

• A. Dry snow over 3 inches
• B. Reports of NIL braking
• C. Ice covering more than 25%
• D. Over 1/2 inch of wet snow, slush or standing water

Answer: (D)

Takeoffs are not permitted when the runway is significantly contaminated because traction and braking are dramatically reduced, making it impossible to guarantee a safe takeoff within the available runway. The specific threshold used here is more than half an inch of wet snow, slush, or standing water. At that depth, friction is enough suppressed that the required takeoff performance can’t be assured and you risk an overrun or loss of directional control.

Other conditions listed are hazardous and would typically warrant caution or grounding if encountered, but the rule in this scenario centers on that 0.5-inch contamination depth as the point at which a takeoff must be refused. Dry snow, even if several inches deep, can sometimes be managed with adjusted performance data; ice coverage and nil braking reflect serious hazards, but the guidance used for this item emphasizes the half-inch threshold as the decisive factor.