AS9120B, ISO 9001:2015, and FAA AC 0056B ACCREDITED

The Operation of Auxiliary Power Units (APUs) in Aircraft

As a reliable source of ground power during certain phases of flight, auxiliary power units (APUs) play a crucial role in aircraft operations. These compact engines are designed to provide electrical power and compressed air to aviation systems when the main engines are not operational. To better understand these complex apparatuses, we will explore APUs by shedding light on their significance and functionality so that you can best find a solution for your needs when demanded.

Located in the tail section of an aircraft if the model features one, an APU is a self-contained engine that consists of a small gas turbine assembly, similar in design to the main turbine engines. An APU is typically fueled by Jet-A fuel and works independently of the main engines. More specifically, when additional power is required or the engines are off, these machines step in as an auxiliary power source during various operations, such as pre-flight checks, taxiing, boarding, and specific flight phases.

As stated before, one of the primary functions of an APU is to generate electrical power. An APU drives an alternator or generator, which produces electrical energy to power numerous onboard systems. These systems include avionics, lights, air conditioning, and entertainment systems. As a result, the aircraft can manage independently from external power sources while on the ground, ensuring continuous functionality of critical systems.

Another vital role of an APU is to generate compressed air, which is subsequently used for a range of applications, such as starting the main engines, operating air conditioning packs, pressurizing the aircraft cabin, and supplying air to pneumatic systems. The APU's ability to supply compressed air independently is particularly valuable during ground operations, as it allows for climate control and system functionality before the main engines are started.

In addition to electrical power generation, some APUs for specific vessel types also contribute to the operation of hydraulic systems. This is most commonly seen in space shuttles, where an APU is used to provide hydraulic power for the gimballing of engines and other processes. While this is extremely beneficial for space operations, APUs for hydraulic power are less common for aviation endeavors.

Alongside their important functions, APUs also significantly contribute to overall fuel efficiency and emissions reduction. By utilizing a separate and smaller engine for tasks that do not require the full power of the main engines, APUs help conserve fuel and reduce environmental impact. This overlaps with the benefit of powering essential systems independently to permit the aircraft to perform more efficiently and minimize the need for external power sources.

By ensuring the availability of essential systems when the main engines are not running, APUs are indispensable components that enhance safety, functionality, and passenger comfort. If you require APU parts for your aircraft or any other items, it is essential to source from a reputable distributor like Automatize Procurement. Our goal is not only to improve the parts procurement process, but to also revolutionize it altogether. To begin procuring the items you require with ease, we invite you to explore our expansive catalog of available products, which have been organized into relevant categories for your benefit. For more information about our various listings and services, contact us via phone or email at any time; we are available around the clock for customer inquiries!


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