11. Who is responsible for the Preflight Contamination Check? While performing the check you notice a very thin layer of hoar frost on the upper surface of the wings. Is this acceptable
Answer: The Captain must determine if deicing is required as soon as practical and communicate any deicing requirements to the Operations Agent or Station Operations. Hoar frost on the upper wing surfaces is not acceptable. All leading edge devices, control surfaces, tab surfaces, upper wing surfaces, and winglets must be free of frost, snow, and ice. The best vantage point for upper wing surface inspection is from the Passenger cabin. Thin hoar frost is acceptable on the upper surface of the fuselage provided all vents and ports are clear. Thin hoar frost is a uniform white deposit of fine crystalline texture, which usually occurs on exposed surfaces on a cold and cloudless night, and which is thin enough to distinguish surface features underneath, such as paint lines, markings, or lettering.