GPU

GPU (Ground Power Unit) is a mobile or fixed ground-based power source that supplies electrical power (typically 28V DC or 115V/400Hz AC) to the aircraft while parked at the gate or on the ramp. Using a GPU instead of the aircraft APU saves fuel, reduces emissions and noise, and decreases APU wear.

Many modern airports provide fixed 400Hz power connections at each gate (PCA — Pre-Conditioned Air and electrical), reducing the need for mobile GPUs.