The bleed air from the low-pressure compressor of the engine is decompressed by the pressure regulator and cooled by the pre-cooling air valve, and then enters the air supply main pipe at 35psi (2.4 atmospheres) and 220 degrees Celsius, and flows through the engine hanger, the leading edge of the large wing, and the front wall of the wheel well. After the board enters two air conditioning components located in the belly of the aircraft.

When traveling by plane, whether it is boarding or flying at an altitude of 10,000 meters, the appropriate temperature and fresh air in the cabin are the basis for a pleasant travel. And these are the important tasks of the air management system.

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.