Takeoff is permitted with frost on which surfaces under which condition?

• A. Upper surface of the fuselage if surface features can be distinguished; and a maximum of 1/8 inch frost on the underside of the wing from cold-soaked fuel
• B. Frost on wings is always permitted
• C. Any frost condition is permitted on takeoff
• D. Frost on tail surfaces only

Answer: (A)

Frost limits for takeoff are about keeping the airplane’s lifting surfaces free enough to maintain proper airflow. The best allowance here is that frost on the upper fuselage can be accepted if you can still clearly distinguish surface features, meaning the frost isn’t thick enough to hide the texture of the skin or obscured lines that indicate the surfacing. In addition, a very small amount of frost on the underside of the wing—up to about 1/8 inch—may be allowed if it comes from cold-soaked fuel; this is considered minor and less likely to significantly disrupt lift.

These conditions reflect the idea that the primary risk is frost on the wings’ lifting surfaces, especially the upper wing, which can severely reduce lift and alter stall characteristics. So, takeoff with frost on wings is not permitted in general, and frost on tail surfaces is not acceptable. The allowed scenario points to limited frost on non-critical areas or extremely light frost on the underside of the wing, under specific circumstances.