Which system would likely require deicer boots?

Deicer boots are specifically designed to remove ice buildup on the wings and tail surfaces of an aircraft. They are most commonly utilized in aircraft that operate at high altitudes, where the temperatures can drop significantly and conditions conducive to ice formation are prevalent. At these altitudes, the aircraft might encounter supercooled water droplets that freeze upon contact with the aircraft surfaces, leading to a dangerous increase in weight and degradation of aerodynamic performance.

In contrast, aircraft operating in tropical regions typically experience warm temperatures that do not promote ice formation, making deicer boots unnecessary. Short haul flights may not ascend to altitudes where icing conditions are likely to occur. Military drones, while they may operate at various altitudes, often have different means of dealing with icing or may be designed to avoid such conditions altogether. Therefore, the use of deicer boots is most critical for aircraft frequently flying in high-altitude environments where freezing conditions are a significant concern.