What is the function of a Ground Power Unit (GPU)?

The function of a Ground Power Unit (GPU) is to supply electrical power to an aircraft while it is on the ground. This is crucial for operating systems such as lighting, avionics, and cabin services when the engines are not running. Using a GPU helps conserve fuel and reduces wear on the aircraft's engines since those systems can draw power from this external source instead of relying on the engines themselves.

Powering the engines during flight does not involve a GPU; the engines produce their own electrical power during this time. Additionally, in-flight entertainment systems are typically powered through the aircraft's internal systems or on-board power generated by the engines. Navigating the aircraft on the ground is managed by ground crew and the aircraft's own systems, unrelated to the primary function of the GPU.