DISTRIBUTION - DESCRIPTION AND OPERATION
** ON A/C NOT FOR ALL
1. General
The pneumatic system is divided into sub-systems as follows:
The pneumatic system is divided into sub-systems as follows:
A. Temperature and Pressure Regulating System for the Bleed Air from the Engine Compressor (Ref. 36-11-00).
This system is installed in the nacelle and pylon of each engine and includes:
This system is installed in the nacelle and pylon of each engine and includes:
- An Intermediate Pressure Bleed Check (IPC) Valve
- A High Pressure Bleed Valve (HPV)
- A Pressure Regulator Bleed Valve (PRV) which permits or stops the bleed air supply. A distribution clapper allows feed the closing chamber will the opening chamber comes to ambient pressure, ensuring the closing function. to a specified limit with a Bleed.
- An Over-Pressure Valve (OPV) which protects the downstream pneumatic system if the PRV does not operate
- A bleed air precooler exchanger (air-to-air) which controls the air temperature downstream of the system. The engine fan supplies cooling air through a Fan Air Valve (FAV) to the precooler.
- A Fan-Air Valve Control Thermostat installed downstream of the precooler controls the butterfly plate of the FAV
- An Exchanger Outlet Temperature Sensor which monitors the temperature in the ducts
- Two pressure transducers which monitor the pressure in the ducts
- Two Bleed-air Monitoring Computers (BMC1 and BMC2) which receive information from the sensors. They monitor the system and control its operation
- Two temperature sensors which detect overtemperature in ducts and give temperature indication.
B. Bleed Air and Crossbleed (Crossfeed) System of the Auxiliary Power Unit (APU) (Ref. 36-12-00)
This system is installed in the MID and AFT fuselage and contains:
This system is installed in the MID and AFT fuselage and contains:
- A crossbleed valve which isolates or connects the right and left bleed air and distribution systems
- An APU bleed load valve which is a part of the APU. This valve controls the bleed air flow from the compressor of the APU when the supply system of the engine is off or does not operate
- An APU bleed check valve in the APU duct which protects the APU against bleed air from the engine(s).
C. Ground Supply of Compressed Air (Ref. 36-13-00)
This system is installed in the lower MID fuselage on the left side and includes a ground connector behind panel 191DB. A check valve is installed inside the ground connector. This stops the loss of air when the ground supply unit is not connected. The HP air is supplied to the distribution systems through the ground connector.
This system is installed in the lower MID fuselage on the left side and includes a ground connector behind panel 191DB. A check valve is installed inside the ground connector. This stops the loss of air when the ground supply unit is not connected. The HP air is supplied to the distribution systems through the ground connector.
D. Environment Protection (Ref. 36-14-00)
- Ventilation of the Wing Leading Edge
This system is installed between the engine pylons and the fuselage. The air which flows into the NACA ram air inlet decreases the temperature of the wing leading edge in this area and ensures correct removal of fuel fumes. - Protection of the Pylon and the Nacelles
This system is installed between the engine pylons and the fuselage. It has a protection function of the wing leading edge and the nacelle. If there is a major leak in the pneumatic system, a door opens and the pressure is released.
Pneumatic System-Schematic