Which ice type is primarily formed from the freezing of supercooled droplets upon contact with the aircraft?

Rime ice is primarily formed when supercooled droplets of water come into contact with an aircraft's surfaces and freeze almost instantaneously. This process occurs in conditions typical of stratiform clouds or in relatively low-temperature environments where the atmosphere contains supercooled water droplets. The rapid freezing leads to the formation of rime ice, which typically appears as a white, frosty coating on leading edges and other parts of the aircraft.

The key aspects of rime ice formation are the presence of supercooled water droplets and the immediate freezing upon contact with a surface that is at or below freezing. This type of ice is characterized by its rough texture and lower mass compared to clear ice, which is formed in other conditions. Understanding the mechanisms of rime ice formation is crucial for aviation safety and for implementing de-icing and anti-icing measures.