At what temperatures does structural icing typically occur?

Structural icing typically occurs in temperatures ranging from just above freezing to quite below zero, generally between +2 degrees and -10 degrees Celsius. At these temperatures, supercooled water droplets can exist within clouds. When aircraft fly through such conditions, these droplets can freeze upon contact with the aircraft surfaces, leading to ice accumulation.

The range identified in the correct answer encompasses a wider span of temperatures (from +2 to -20 degrees Celsius) where structural icing is a significant concern. This is particularly critical for pilots and air traffic controllers to be aware of since ice accumulation can severely affect aircraft performance, leading to increased drag and decreased lift.

In contrast, the other options provide either a narrower temperature range or encompass less critical points for icing conditions. Selecting the broadest and most accurate temperature range for structural icing ensures a better understanding of when such hazards are most likely to occur, which is vital for safe aviation operations.