W DOC AIRBUS | AMM A320F

INDICATING - DESCRIPTION AND OPERATION

** ON A/C NOT FOR ALL
1. General
The indicating system shows the condition of the pneumatic system. It monitors the bleed air pressure and temperature (Ref. AMM D/O 36-21-00-00) and the position of the different valves. The indicating system also shows the bleed-air duct leaks that the leak detection system finds (Ref. AMM D/O 36-22-00-00). The primary indications are shown on the lower ECAM display unit (Ref. AMM D/O 31-67-00-00) and the upper ECAM display unit (Ref. AMM D/O 31-66-00-00). Indications are also shown on the AIR COND panel 30VU.
** ON A/C NOT FOR ALL
2. Component Location
F AIR COND Overhead Panel, ECAM and CFDS - Component Location ** ON A/C NOT FOR ALL
F Bleed Monitoring Computer - Component Location ** ON A/C NOT FOR ALL
The indicating system includes the following main components:
  • AIR COND overhead panel
  • ECAM and CFDS system
  • Bleed Monitoring Computer (BMC).
** ON A/C NOT FOR ALL
3. System Description
F ECAM Control Panel ** ON A/C NOT FOR ALL
F Upper and Lower ECAM Display Units ** ON A/C NOT FOR ALL
F STATUS Page - Lower ECAM Display ** ON A/C NOT FOR ALL
F AIR COND Overhead Panel ** ON A/C NOT FOR ALL
F Lower ECAM Display Unit ** ON A/C NOT FOR ALL
A. Lower and Upper ECAM Display Units
In the correct operating conditions, when you push the BLEED key on the ECAM control panel, the BLEED page is shown on the lower ECAM display unit. The BLEED page shows the parameters related to the bleed-air system operation (regulated pressure, temperature and valve positions).
If a fault occurs (overpressure, overtemperature, incorrect valve position, duct leak) the BLEED page is automatically shown on the lower ECAM display unit. A warning message together with the necessary corrective action is shown on the upper ECAM display unit.
B. AIR COND Panel 30VU
On the AIR COND panel, three BLEED pushbutton switches control the related engine and APU bleed valves. Two ENG BLEED pushbutton switches (ENG 1 BLEED and ENG 2 BLEED) control the related engine bleed pressure regulator valves and HP bleed valves. Each ENG BLEED pushbutton switch has an OFF and a FAULT legend.
The APU BLEED pushbutton switch controls the APU bleed valve. It has an ON and a FAULT legend.
C. Temperature and Pressure Monitoring (Ref. 36-21-00)
Temperature sensors and pressure transducers monitor the temperature and the pressure of the engine bleed air. They transmit temperature and pressure data to the Bleed Monitoring Computers (BMCs) which are installed in the avionics compartment. Valve position switches transmit the valve position data to the BMCs.
The BMCs transmit the bleed-air temperature and pressure data and the valve position data to the System Data Acquisition Concentrators (SDACs). The SDACs transmit the data to the ECAM display unit.
The BLEED page of the lower ECAM display unit shows:
  • The valve positions (HP bleed valves, bleed pressure regulator valves crossbleed valve and APU bleed valve)
  • The duct temperature (downstream of the bleed air precooler exchanger)
  • The duct pressure (downstream of the engine bleed pressure regulator valves).
D. Overheat Detection (Ref. 36-22-00)
The overheat detection system adjacent to the bleed-air ducts monitors the ducts for leaks and bursts. It automatically shuts off the related bleed air supply if a leak or burst occurs on a duct.
The overheat detection loops are installed adjacent to the pneumatic ducts in:
  • The fuselage
  • The belly fairing
  • The wings
  • The engine pylons.
** ON A/C NOT FOR ALL
4. Power Supply
F Indication - Power supply ** ON A/C NOT FOR ALL
F Indication - Electrical Schematic ** ON A/C NOT FOR ALL
The indicating system gets electrical power from the aircraft DC system which supplies 28VDC through circuit breakers 2HA1, 2HA2, 3HA1 and 3HA2 to:
  • The BMC1 and BMC2
  • The relays of the AIR COND overhead panel
  • The ENG/APU FIRE panel (Ref. AMM D/O 26-00-00-00)
  • The pressure transducers.
A. BMC FIN: 1-HA-1 FIN: 1-HA-2
(1) Function
Two BMCs (BMC1 and BMC2) are installed in the FWD avionics compartment. They monitor and control the bleed air system permanently when power is supplied to the aircraft.
The BMCs monitor the valve positions, the pressure and the temperature of the supplied bleed air. Additionally, they monitor different zones to protect the adjacent systems and components against damage if a duct leaks or bursts (ambient overheat). To get correct limits or to prevent abnormal conditions, the BMCs control the necessary position of the valves.
Both BMCs are identical and communicate via an ARINC 429 bus. They receive analog and discrete inputs from interface items and systems. The BMCs process these inputs and transmit analog and discrete outputs to the interface items and systems.
(2) Interfaces
(a) Interface items for the inputs:
  • AIR COND overhead panel
  • Pressure transducers
  • Temperature sensor
  • Valves (bleed pressure regulator valve, HP bleed valve, overpressure valve and fan air valve)
  • APU bleed valve
  • Crossbleed valve
  • Overheat detection loops
  • ENG/APU FIRE panel
  • Electronic Control Box (ECB).
(b) Interfaces items for the outputs:
  • AIR COND overhead panel
  • ECB.
(c) Interface system for the outputs:
  • Environment control system (ECS).
(d) Interface items for the ARINC inputs:
  • Centralized Fault Display Interface Unit (CFDIU)
  • Engine Interface Units (EIU).
(e) Interface items for the ARINC outputs:
  • Opposite BMC
  • CFDIU
  • SDAC.
(3) BITE
The BMCs incorporate a Built-In Test Equipment (BITE). They receive and transmit information from/to the CFDIU. This permits a self-test of the BMCs which is called up from the Multipurpose Control and Display Unit (MCDU) menu.
** ON A/C NOT FOR ALL
5. Operation/Control and Indicating
A. AIR COND Overhead Panel
F AIR COND Overhead Panel, ECAM and CFDS - Component Location ** ON A/C NOT FOR ALL
Three pushbutton switches on the AIR COND overhead panel 30VU control and indicate the condition of the bleed air system.
The ENG 1 BLEED (ENG 2 BLEED) pushbutton switch controls the engine 1 (2) pressure-regulator valve. Each pushbutton switch has two legends:
  • FAULT (amber)
  • OFF (white).
When the ENG 1 BLEED (ENG 2 BLEED) pushbutton switch is pushed, the bleed pressure regulator valve(s) operate(s) automatically. When a pushbutton switch is released (the white OFF legend is on), the valve is closed.
The APU BLEED pushbutton switch controls the APU bleed valve. It has two legends:
  • FAULT (amber)
  • ON (blue).
When the APU BLEED pushbutton switch is released, the APU bleed valve is closed. When the pushbutton switch is pushed (the blue ON legend is on),the APU bleed valve operates automatically.
If a fault occurs, the FAULT legend of the concerned pushbutton switch comes on amber. The related valve automatically closes. At the same time, the ECAM system is activated.
If the fault (overheat, overpressure) disappears and the pushbutton switch is operated, the FAULT legend goes off.
B. ECAM
F AIR COND Overhead Panel, ECAM and CFDS - Component Location ** ON A/C NOT FOR ALL
F ECAM Control Panel ** ON A/C NOT FOR ALL
F Upper and Lower ECAM Display Units ** ON A/C NOT FOR ALL
F STATUS Page - Lower ECAM Display ** ON A/C NOT FOR ALL
If the BLEED key on the ECAM control panel is pushed in normal operating conditions, the BLEED page is shown on the lower ECAM display unit. The BLEED page shows the system parameters (regulated pressure, temperature and valve position).
If a fault occurs (overpressure, overheat) and the FAULT legend of any pushbutton switch on the AIR COND overhead panel comes on:
  • The single chime sounds
  • The MASTER CAUT lights on the CAPT and F/O glareshield panels come on amber
  • The lower ECAM display unit shows the type of fault
  • The upper ECAM display unit shows, in the left bottom corner, the fault in the form of a message and the required action.
The upper ECAM display unit messages are:
  • ENG1(2) BLEED FAULT
  • LEFT (RIGHT) WING LEAK
  • LEFT (RIGHT) PYLON LEAK
  • APU LEAK
  • ENG1(2) PRV NOT AUTOMATICALLY CLOSED DURING ENGINE START
  • ENG1(2) BLEED LO PR
  • X BLEED FAULT
  • ENG1(2) HP VALVE ABNORMALLY CLOSED
  • L (R) WING LEAK DET FAULT
  • BLEED MONITORING FAULT
  • APU BLEED FAULT CLOSED.
The lower ECAM display unit shows, on the STATUS page, the result of the actions. The FAULT legend stays on as long as the ENG 1 BLEED (ENG 2 BLEED) pushbutton switch is not released. When the pushbutton switch is released , the OFF legend comes on (white) and the FAULT legend goes off (only if the associated fault disappears).
The FAULT legend on the APU BLEED pushbutton switch stays on as long as the pushbutton switch is not pushed. When the pushbutton switch is pushed, the ON legend (blue) and the FAULT legend (amber) go off (only if the associated fault is cancelled).
When the FAULT legend of the ENG1 BLEED (ENG2 BLEED) pushbutton switch comes on, the related bleed pressure regulator valve automatically closes.
This also causes the engine 1(2) HP bleed valve to close.
When the FAULT legend of the APU BLEED pushbutton switch comes on, the APU bleed valve automatically closes.
Two BMCs (BMC1 and BMC2) are installed in the FWD avionics compartment. They monitor and control the bleed air system permanently when power is supplied to the aircraft.
The BMC monitors the valve positions, the pressure and the temperature of the supplied bleed air. Additionally they monitor different zones to protect the adjacent systems and components against damage if a duct leaks or bursts (ambient overheat). To get correct limits or to prevent abnormal conditions, the BMCs control the necessary position of the valves.
Both BMCs are identical and communicate via an ARINC 429 bus. They receive analog and discrete inputs from interface items and systems. The BMCs process these inputs and transmit analog and discrete outputs to the interfaced items and systems.
(1) The interface items are:
(a) For the discrete inputs:
  • AIR COND overhead panel,
  • Valves (bleed pressure regulator valve, HP bleed valve, overpressure valve and Fan air valve)
  • APU bleed valve
  • Crossbleed valve
  • ENG/APU FIRE panel
  • Electronic Control Box.
(b) For the discrete outputs:
  • AIR COND overhead panel
  • Electronic Control Box.
(c) For analogic inputs:
  • Pressure transducers
  • Temperature sensors
  • Overheat detection loops.
(2) The interface systems are:
(a) For the discrete outputs:
  • Zone Controller
  • Environmental Control System.
(b) For the ARINC inputs:
  • Centralized Fault Display Interface Unit (CFDIU)
  • Engine Interface Unit
(c) For the ARINC outputs:
  • Bleed Air Monitoring Computer (BMC) opposite
  • Centralized Fault Display interface Unit (CFDIU)
  • System Data Acquisition Concentrator (SDAC).
To indicate the system operation, the BMCs transmit digital outputs through the SDAC to the ECAM system. The digital outputs generate the system display. If an abnormal condition occurs, the ECAM system causes the single chime to sound and the MASTER CAUT light (amber) to flash. At the same time, the BMCs transmit discrete outputs to the AIR COND overhead panel, which causes the FAULT legend to come on amber.
The BMCs are equipped with Built-In Test Equipment (BITE). They receive and transmit information from/to the CFDIU. This permits a self-test of the BMCs which is called up from the MCDU menu.
C. Fault Indicating
(1) With amber FAULT legend on ENG BLEED pushbutton switch, MASTER CAUT light and single chime:
(2) With amber FAULT legend on APU BLEED pushbutton, MASTER CAUT light and single chime:
(3) With amber MASTER CAUT light and single chime but without amber FAULT legend:
(4) Without amber FAULT legend, MASTER CAUT light and single chime:
[Rev.10 from 2021] 2026.04.01 01:16:12 UTC
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