What describes the clean aircraft concept?

• A. An aircraft must not take off when frost, ice, or snow is adhering to the wings, control surfaces, engine inlets, and other critical surfaces of the aircraft.
• B. An aircraft may take off with minor frost on non-critical surfaces.
• C. The concept refers to cleaning the exterior only before flight.
• D. The concept requires de-icing after takeoff.

Answer: (A)

The idea behind the clean aircraft concept is that the aircraft must be free of frost, ice, or snow on all surfaces that affect aerodynamics and engine operation before takeoff. Frost or ice on the wings and control surfaces disrupts the smooth airflow, reducing lift and raising stall speed, while icing in engine inlets can diminish or shut down thrust and impair performance. Because these surfaces are critical to safe flight, takeoff with contamination is not allowed. The other options don’t fit because minor frost on non-critical surfaces still poses risk if any critical surface is affected, the concept isn’t limited to exterior cleaning only, and de-icing after takeoff contradicts the requirement that surfaces be clean before departure.