How do temperature extremes affect APU function?

Temperature extremes can significantly impact the function of an Auxiliary Power Unit (APU) in several ways. When temperatures fluctuate widely, both hot and cold conditions can influence various aspects of APU operation and performance.

In extreme cold, the fuel can gel, leading to difficulties in starting the APU and maintaining operational efficiency. Additionally, lubrication in the engine components may become thicker, increasing friction and potentially leading to wear or failure. Conversely, overly hot conditions can cause the APU to overheat, risking damage to sensitive components and reducing efficiency.

These factors combined affect ignition reliability, fuel consumption rates, and the overall performance of the APU. Hence, this choice accurately captures the complexity of how temperature extremes can influence multiple critical operational areas within the APU system.