Induction icing can occur under which conditions?

Induction icing occurs when supercooled water droplets come into contact with aircraft structures, particularly the engine's air intake, under specific atmospheric conditions. The correct choice indicates that induction icing can happen during clear skies and above freezing temperatures. This is important because supercooled water can exist at temperatures above freezing, especially when humidity is high and the droplets remain in a liquid form despite ambient temperatures being above zero degrees Celsius.

For instance, an aircraft can encounter such conditions at altitudes where the temperature is low enough for visible moisture to condense and freeze as it enters the engine intake, leading to potential icing issues. This indicates that induction icing is not solely dependent on subfreezing temperatures, thereby illustrating the need to be vigilant about weather conditions that could lead to the presence of supercooled water.

The other choices are limited in scope. Induction icing is not restricted to thunderstorms, and while it is more common in colder temperatures, it can also happen above freezing due to the presence of supercooled droplets. Furthermore, icing can occur during level flight, not just during climbs or descents. Understanding this helps pilots recognize the risk of icing in a wider range of conditions, emphasizing the importance of weather awareness during all phases of flight.