Aircraft ground air conditioning (hereinafter referred to as PCA) is an air conditioning unit that provides fresh air suitable for temperature and humidity environment and physiological needs for passengers and crew members parked on the boarding bridge at the airport, which provides a comfortable environment during ground maintenance.

At present, there are general aircraft ground air conditioning air supply hoses​, which are used to deliver fresh air with a certain flow, temperature and pressure from the aircraft ground air conditioning to the air conditioning interface of the aircraft fuselage from the air outlet of the air conditioner. However, this type of general aircraft ground air-conditioning air supply hose generally has a length ranging from 10 to 40 meters, and the length is longer.

Pre-conditioned air unit​ is a brand-new type of air-conditioning unit that is placed outside of civil aviation aircraft and uses long air supply ducts and aircraft-specific connectors to supply air to the cabin through the external air-conditioning interface at the lower part of the aircraft fuselage and the complex air supply ducts inside the fuselage wind special air conditioner.