What does APU stand for in aviation?

The term APU stands for Auxiliary Power Unit in aviation. An APU is a crucial component found on many commercial and military aircraft, serving several important functions. Its primary role is to provide electrical power and bleed air for starting the main engines and for powering systems on the aircraft when the engines are not running, such as during ground operations. This allows the aircraft to operate systems like lighting, air conditioning, and avionics while on the ground without needing to run the main engines, which enhances fuel efficiency and reduces emissions during these times. Additionally, it can be used to provide power during emergency situations if the main engines fail. Understanding the function and purpose of an APU is essential for anyone involved in aircraft operations or maintenance, as it contributes significantly to the overall efficiency and effectiveness of aircraft operation.