Which of the following is an effect of insufficient cooling on an APU?

Insufficient cooling in an Auxiliary Power Unit (APU) can lead to various negative consequences, one of the most critical being an increased likelihood of overheating. When the cooling system does not effectively dissipate heat generated by the APU during operation, the temperature can rise to unsafe levels. This overheating can cause damage to internal components, reduce efficiency, and may lead to complete failure of the unit if not addressed.

Maintaining adequate cooling is vital for the reliable operation of the APU, as it ensures that the temperatures remain within prescribed operational limits. This helps preserve the integrity of the engine and avoids costly repairs or replacements due to heat damage.

In contrast, options indicating improved fuel economy, enhanced engine power, or decreased operational costs do not directly result from insufficient cooling. Instead, these options generally describe outcomes associated with proper functioning and efficiency, not the adverse effects of inadequate cooling.