DOC AIRBUS | AMM A320FCOMPRESSOR BLEED AIR - DESCRIPTION AND OPERATION
** ON A/C NOT FOR ALL
1. Component Location
** ON A/C NOT FOR ALL 
Air System (HPC Bleed Valve and Sensor)- The HPC bleed valve air pressure sensor is attached to the Compressor Intermediate Case (CIC) bulkhead at the 2 o'clock engine position.
- The Low Pressure Compressor (LPC) 2.5 bleed valve actuator is mounted at the rear of the CIC fire seal at approximately the 10 o'clock position.
- The HPC bleed valve is attached to the diffuser case at the 1 o'clock position.
| FIN | FUNCTIONAL DESIGNATION | PANEL | ZONE | ACCESS DOOR | ATA REF |
|---|---|---|---|---|---|
| ** ON A/C NOT FOR ALL | |||||
| 4058KS | HPC BLEED VALVE AIR PRESSURE SENSOR | 400 | 73-11-00 | ||
| 4092KS | ACTUATOR-LPC BLEED VALVE | 400 | 73-11-00 | ||
| 4102JM | HPC BLEED VALVE | 400 | 73-11-00 | ||
2. System Description
A. Compressor Bleed Air System
(1) 2.5 Bleed Assembly
(a) The 2.5 bleed assembly is attached to the LPC assembly immediately forward of the CIC.
(b) The assembly has a 2.5 bleed valve ring, two sealing rings, linkage and a bell crank which moves the valve ring to the open or closed position.
(c) The 2.5 bleed valve actuator is used to actuate the 2.5 bleed valve assembly. The actuator is mounted at the rear of the CIC fire seal at approximately the 10 o'clock position. A connecting link transmits actuator motion to the 2.5 bleed valve assembly.
(d) The Electronic Engine Control (EEC) controls the 2.5 bleed actuator position through a dual coil torque motor which controls a servo valve.
(e) The 2.5 bleed valve actuator position is sensed by temperature compensated dual coil Linear Voltage Differential Transducers (LVDTs). The LVDTs transmit actuator position to each channel of the EEC.
(f) The 2.5 bleed valve actuator is connected to the EEC by an electrical harness and is hydraulically actuated (fuel).
(g) The actuator is scheduled based on the N1 (LPC) correct speed.
(h) Usually, the valve is open at start and idle, and closed at aircraft takeoff.
(2) HPC Bleed Valve
(a) This valve is a two-position (open/closed) inverted poppet-type valve which is spring-loaded to the open position. The bleed valve receives pressure from the HPC 6th stage bleed air for closing.
(b) The bleed valve bleeds air from the 6th stage high compressor during engine start. The valve is spring-loaded open and will close during engine start when the HPC 6th stage air pressure is large enough to overcome the spring force.
(3) HPC Bleed Valve Pressure Sensor
(a) The pressure sensor is located approximately at the 2 o'clock position on the CIC fire seal.
(b) The sensor provides feedback to the EEC. The sensor is used as a notification if the bleed valve fails to open and the engine core area is exposed to compressor air after engine start. The sensor is also used as notification if the bleed valve failed to close during engine start.
(c) The sensor measures the rise in pressure when the bleed valve is open during and after engine start-up and provides feedback to the EEC.
(d) The sensor is a dual channel absolute pressure sensor with a single connector.