What is Preconditioned air (PCA) and ground power units (GPU)?
Preconditioned air (PCA) and ground power units (GPU) are gate systems that supply parked aircraft with conditioned air and electrical power. They let airlines keep the aircraft's auxiliary power unit switched off at the stand, cutting fuel burn, emissions and noise, while shifting that energy load onto the airport's own electrical and cooling systems.
What it is
While an aircraft is parked, it still needs cabin cooling or heating and electrical power. Without gate services, it runs its auxiliary power unit (APU), a small jet engine in the tail. PCA units deliver conditioned air through a hose to the aircraft, and GPUs supply electrical power at the frequency aircraft use.
PCA can be a standalone unit at each gate or served from a central chilled water plant. GPUs can be fixed to the boarding bridge or mobile. Both are significant electrical loads, and PCA units in hot climates can run for long periods.
PCA and GPU only deliver their benefit if they are available, connected and used. Units that are faulty, left running with no aircraft, or not connected because of slow turnaround procedures waste energy or push airlines back to the APU.
Who it applies to / where it is used
PCA and GPU are used at airport contact stands and some remote stands. Airport operators, ground handlers and airlines share responsibility. Many airports set APU usage restrictions, so reliable gate services matter for both operations and environmental programs.
How it is measured / what evidence it needs
The useful evidence is availability and use per gate, matched with the energy each unit draws.
- PCA and GPU electrical energy per gate
- Run time with and without an aircraft connected
- Availability and fault events per unit
- PCA supply air temperature and flow
- Connection time compared with aircraft time on stand
How Aqueduct helps
Aqueduct treats every gate as a measured asset, so energy, availability and use can be managed together.
- aQ EnergySmart meters PCA and GPU energy by gate and flags units running with no aircraft
- aQ PredictIQ watches compressors, fans and converters for early signs of failure
- Faults route into the customer's CMMS so units are back in service sooner
- Measured records support the airport's carbon reporting, which the airport prepares