Ground power units (GPUs) are a complex tool that require regular maintenance and frequent calibration. Due to the equipment’s multiplex structure, there are many areas to be inspected. To ensure all areas are addressed during scheduled maintenance and calibration, we have complied a short maintenance guide.
When performing GPU inspection, it is important to pay close attention to the following components:
THE COOLING SYSTEM
Proper functionality of a GPU’s cooling system is of utter importance. This is due to the long hours in which the cooling system usually runs. When inspecting the cooling system be sure to check the following:
This should always be kept full with half containing antifreeze and the other half containing a water mixture.
This piece should be set at the correct pressure for the system (done through calibration) and should contain clean and straight radiator fins.
These should be leak free and all clamps should be tightened.
After all components of the cooling system have been checked. Calibration should be performed to ensure pressure measurements are accurate and precise.
During maintenance, the chassis and running gear should always be inspected for the following:
Should be cleaned and repacked. This should occur every 2,000 hours or every two years, whichever is reached first.
The latch should lock the tow bar tightly into place without any “play.”
Should be properly inflated and checked for correct alignment.
Checked for proper adjustment and functionality.
OTHER IMPORTANT TIPS
- If a GPU last inspection has been more than 300 hours, oil filter and fuel filter changes need to be performed.
- If the air filter is dirty is should be replaced.
- Accessory belts should be inspected for cracks and tightened.
- Intake hoses and exhaust piping should be tightened.
After inspecting and repair all GOU components, calibration of the following should be completed to ensure accuracy and proper functionality of the GPU:
The generator is one of the key pieces in functionality of a GPU. The generator must be calibrated to exact specs to ensure that the aircraft is accepting power from the GPU. A generator must also be calibrated to ensure that the correct voltage of power is being transferred to the aircraft. If too high of a voltage is transferred, aircraft damage is likely, which could result in costly repairs.