The RAT is the auxiliary pressure source for the blue hydraulic system and emergency electric constant speed motor/generator (CSM/G). RATs are deployed automatically or manually based on failure conditions. It pressurizes the blue hydraulic system to 2500 psi. According to specific maintenance procedures, it can only be retracted on the ground.

Air Conditioning System Related Malfunctions1. Sensor, relay failure(1) During the entire control process of the air-conditioning system, the controller processes and issues control signals by receiving the signals from each temperature sensor.

The air-conditioning system​ ensures a constant supply of fresh air and maintains a constant selected temperature in the three areas of the cockpit, front cabin and rear cabin, mainly by conditioning the air entering the interior of the cabin. The air entering the cabin is regulated by mixing cold air and bleed air to the right temperature.