DOC AIRBUS | AMM A320FENGINE AIR INTAKE ICE PROTECTION - DESCRIPTION AND OPERATION
** ON A/C NOT FOR ALL
** ON A/C NOT FOR ALL
** ON A/C NOT FOR ALL
** ON A/C NOT FOR ALL
1. General
The ice protection system of the engine air intake supplies and controls a flow of hot air from the engine to the air intake cowl. This prevents ice on the intake cowl during engine operations. The ice protection components are interchangeable between engines.
** ON A/C NOT FOR ALL The ice protection system of the engine air intake supplies and controls a flow of hot air from the engine to the air intake cowl. This prevents ice on the intake cowl during engine operations. The ice protection components are interchangeable between engines.
Engine Air-Intake Ice-Protection2. Component Location
** ON A/C NOT FOR ALL | FIN | FUNCTIONAL DESIGNATION | PANEL | ZONE | ACCESS DOOR | ATA REF |
|---|---|---|---|---|---|
| ** ON A/C NOT FOR ALL | |||||
| 2DN1 | P/BSW-ANTI ICE/ENG 1 | 25VU | 210 | 30-21-00 | |
| 2DN2 | P/BSW-ANTI ICE/ENG 2 | 25VU | 210 | 30-21-00 | |
| 4010DN | PRSOV1-AIR INTAKE ANTI ICE | 400 | 30-21-00 | ||
| 4011DN | PRSOV2-AIR INTAKE ANTI ICE | 400 | 30-21-00 | ||
| 4002DN | PRESS XDCR-ENGINE AIR INTAKE ANTI ICE, 2 | 400 | 30-21-00 | ||
| 4003DN | PRESS XDCR-ENGINE AIR INTAKE ANTI ICE, 1 | 400 | 30-21-00 | ||
| 4160KS | THERMOCOUPLE ASSEMBLY, OVERHEAT INDICATION, FAN CASE | 400 | 73-11-00 | ||
| 4190KS | NAI SOLENOID BLOCK | 463 | 73-11-00 | ||
3. System Description
The Nacelle Anti-Ice (NAI) system is the same for engine 1 and engine 2.
The NAI system supplies hot air bleed from the HP6 engine bleed port of the engine compressor to the engine nose cowl. The hot air flows through a feed duct, two Pressure Regulating and Shut-Off Valves (PRSOVs) in the core zone and is released through nozzles into the air intake lip.
An injector system gives a swirling movement to the hot air in the air intake to prevent ice accretion. Then, the air is released overboard through an exhaust grid.
It is possible to lock the valves manually in the open position.
The system is controlled on the ground or in flight, when you push or release the ENG pushbutton switch on the ANTI ICE section of overhead control and indication panel 25VU.
The Electronic Engine Control (EEC) controls two solenoids. Each solenoid controls each shut off valve.
In normal operation, when the ANTI ICE/ENG1(2) pushbutton switch is released (the ON legend is off):
When the ANTI ICE/ENG1(2) pushbutton switch is pushed (the ON legend is on):
The PRSOVs do the shut-off function in normal mode and the regulation function.
The system must prevent overheat of the air inlet skin.
Two pressure transducers are used to monitor the system. They send the measured pressure values to the EEC. Then the EEC calculate this data with the other parameters to get the system status data (low or high pressure). Then, it transmits these data to the Engine Interface Unit (EIU) application.
** ON A/C NOT FOR ALL The Nacelle Anti-Ice (NAI) system is the same for engine 1 and engine 2.
The NAI system supplies hot air bleed from the HP6 engine bleed port of the engine compressor to the engine nose cowl. The hot air flows through a feed duct, two Pressure Regulating and Shut-Off Valves (PRSOVs) in the core zone and is released through nozzles into the air intake lip.
An injector system gives a swirling movement to the hot air in the air intake to prevent ice accretion. Then, the air is released overboard through an exhaust grid.
It is possible to lock the valves manually in the open position.
The system is controlled on the ground or in flight, when you push or release the ENG pushbutton switch on the ANTI ICE section of overhead control and indication panel 25VU.
The Electronic Engine Control (EEC) controls two solenoids. Each solenoid controls each shut off valve.
In normal operation, when the ANTI ICE/ENG1(2) pushbutton switch is released (the ON legend is off):
- The upper valve solenoid is energized, and
- The contact of the upper shut-off valve goes to the open position, and
- The upper valve goes in a closed position.
When the ANTI ICE/ENG1(2) pushbutton switch is pushed (the ON legend is on):
- The valves solenoids are de-energized, and
- The contact of the shut-off valves go to the closed position, and
- The NAI valves go in an open position, only the upper valve controls the air flow of the hot air.
The PRSOVs do the shut-off function in normal mode and the regulation function.
The system must prevent overheat of the air inlet skin.
Two pressure transducers are used to monitor the system. They send the measured pressure values to the EEC. Then the EEC calculate this data with the other parameters to get the system status data (low or high pressure). Then, it transmits these data to the Engine Interface Unit (EIU) application.
4. Power Supply
There is no power supply for this system. The solenoids and the pressure transducers are power supplied by EEC.
** ON A/C NOT FOR ALL There is no power supply for this system. The solenoids and the pressure transducers are power supplied by EEC.
5. Interface
A. Interface with the Engine Interface Unit (EIU)
The EIU receives inputs from the ENG 1(2) pushbutton switches on the ANTI ICE section of panel 25VU and its input is transmitted to the FADEC by an ARINC 429 bus (label 032 bit 22). The FADEC uses this bit to select the continuous ignition.
When the ENG 1(2) pushbutton switch is pushed (ON legend in on), EIU2(1) receives a ground signal and EIU1(2) receives a ground/open signal.
When the ENG 1(2) pushbutton switch is released (ON legend in off), EIU1(2) receives a ground signal and EIU2(1) receives a ground/open signal.
The EIU transmits the signal to:
The EIU receives inputs from the ENG 1(2) pushbutton switches on the ANTI ICE section of panel 25VU and its input is transmitted to the FADEC by an ARINC 429 bus (label 032 bit 22). The FADEC uses this bit to select the continuous ignition.
When the ENG 1(2) pushbutton switch is pushed (ON legend in on), EIU2(1) receives a ground signal and EIU1(2) receives a ground/open signal.
When the ENG 1(2) pushbutton switch is released (ON legend in off), EIU1(2) receives a ground signal and EIU2(1) receives a ground/open signal.
The EIU transmits the signal to:
- The Flight Warning System (FWS) through the ARINC 429 bus
- The Centralized Fault Display Interface Unit (CFDIU) through the ARINC 429 bus
- The Flight Data Interface and Management Unit (FDIMU) through the ARINC 429 bus.
B. Interface with the EEC
The EEC controls the NAI system directly. The EEC and the EIU monitor the NAI system.
The ENG 1 and ENG 2 pushbutton switches on the ANTI ICE section of panel 25VU transmit the ON position (ground signal) to channel A of the EEC.
Channel A and channel B are connected and they communicate with each other.
If a failure occurs in one channel, the other channel will collect information from the defective channel to replace the channel that has the failure.
The EEC sends a signal to the FWS.
The EEC supplies the NAI valve solenoids and the pressure transducers.
The EEC controls the NAI system directly. The EEC and the EIU monitor the NAI system.
The ENG 1 and ENG 2 pushbutton switches on the ANTI ICE section of panel 25VU transmit the ON position (ground signal) to channel A of the EEC.
Channel A and channel B are connected and they communicate with each other.
If a failure occurs in one channel, the other channel will collect information from the defective channel to replace the channel that has the failure.
The EEC sends a signal to the FWS.
The EEC supplies the NAI valve solenoids and the pressure transducers.
6. Component Description
A. Pressure Regulating and Shut-Off Valves (PRSOVs)
The PRSOVs are installed in the core zone and operate at a very high temperature.
The PRSOVs have two functions:
If there is a dust burst in the fan zone, they also have an isolation function.
When the engine operates, the EEC controls the PRSOVs as follows:
If there are no air pressure and electrical commands, the valves of the PRSOV units are fully open.
PRSOV1 is connected to the sixth-stage bleed port.
PRSOV1 gives a stable pressure during all the engine transient conditions. When PRSOV1 is failed open or set as locked open manually, PRSOV2 gives a stable pressure during all the engine transient conditions.
The PRSOVs are installed in the core zone and operate at a very high temperature.
The PRSOVs have two functions:
- The shut-off function
- The regulation function.
If there is a dust burst in the fan zone, they also have an isolation function.
When the engine operates, the EEC controls the PRSOVs as follows:
- If the valves of the PRSOVs are not found failed open ('Upstream NAIV Failed Open' is false for channel A or 'Downstream NAIV Failed Open' is false for channel B), the channel in control energizes its solenoid.
- If the valve controlled by the channel in control is found failed open ('Upstream NAIV Failed Open' is true for channel A or 'Downstream NAIV Failed Open' is true for channel B), the channel that is not in control energizes its solenoid.
- The upstream valve (PRSOV1) controls the pressure between 59 psi (4.07 bar) and 87 psi (6.00 bar) related to the engine air pressure and the temperature.
- The downstream valve (PRSOV2) controls the pressure between 86 psi (5.93 bar) and 115 psi (7.93 bar) related to the engine air pressure and the temperature.
If there are no air pressure and electrical commands, the valves of the PRSOV units are fully open.
PRSOV1 is connected to the sixth-stage bleed port.
PRSOV1 gives a stable pressure during all the engine transient conditions. When PRSOV1 is failed open or set as locked open manually, PRSOV2 gives a stable pressure during all the engine transient conditions.
B. Engine Anti-Ice Ducts
The NAI system ducting is used to supply air from the High-Pressure Compressor (HPC) to the swirl system in the engine air-intake cowl.
The ducts have an insulation in the fan compartment.
There are four engine anti-ice ducts:
The NAI system ducting is used to supply air from the High-Pressure Compressor (HPC) to the swirl system in the engine air-intake cowl.
The ducts have an insulation in the fan compartment.
There are four engine anti-ice ducts:
- The forward NAI duct
- The middle NAI duct
- The short NAI duct
- The aft NAI duct.
The aft duct sends HP6 engine hot-air to the upper anti-ice PRSOV. The short duct sends HP6 air from the upper PRSOV to the lower PRSOV. The middle duct and the forward duct send the HP6 air from the lower PRSOV to the engine air-inlet cowl, through the lower bifurcation firewall.
C. Pressure Transducers
The first pressure transducer is installed in the core compartment near the solenoid manifold to prevent high temperature around the valve. The upstream pressure transducer measures the downstream valve sense-line pressure. There is one single channel (only connected to EEC channel B), because of the pressure information that is consolidated with the downstream pressure transducer.
The second pressure transducer is installed downstream of PRSOV2 (downstream valve) in the fan compartment, near the interface with the inlet. The downstream pressure transducer sense the pressure downstream of the two PRSOVs. It is a dual-channel sensor connected to the EEC to keep the monitoring function if a failure of the EEC channel occurs.
The first pressure transducer is installed in the core compartment near the solenoid manifold to prevent high temperature around the valve. The upstream pressure transducer measures the downstream valve sense-line pressure. There is one single channel (only connected to EEC channel B), because of the pressure information that is consolidated with the downstream pressure transducer.
The second pressure transducer is installed downstream of PRSOV2 (downstream valve) in the fan compartment, near the interface with the inlet. The downstream pressure transducer sense the pressure downstream of the two PRSOVs. It is a dual-channel sensor connected to the EEC to keep the monitoring function if a failure of the EEC channel occurs.
D. Swirl Nozzles
The swirl system has three nozzles that mix the air and supply it to the D-duct. It has three functions:
The swirl system has three nozzles that mix the air and supply it to the D-duct. It has three functions:
- It makes flow homogenization before entry in the D-duct.
- It prevents the unwanted effect of the hot air on the inlet and thus overheating conditions.
- It gives a one-stage jet-pump effect for better recirculation.
E. Maintainability
The engine air-intake ice-protection has a special remote override-mechanism installed on the PRSOVs to lock open the valves. It is not necessary to open the engine thrust-reverser cowl-doors to lock the valves with this system.
There are manual override interfaces dedicated for the NAI valves on the right thrust-reverser cowl-door.
After a maintenance task, it is necessary to do an operational test of the NAI valves. This operational test of the valves is done on the ground while the engine starts. If there is no failure after the engine starts, the NAI valves will be serviceable during the operations.
The engine air-intake ice-protection has a special remote override-mechanism installed on the PRSOVs to lock open the valves. It is not necessary to open the engine thrust-reverser cowl-doors to lock the valves with this system.
There are manual override interfaces dedicated for the NAI valves on the right thrust-reverser cowl-door.
After a maintenance task, it is necessary to do an operational test of the NAI valves. This operational test of the valves is done on the ground while the engine starts. If there is no failure after the engine starts, the NAI valves will be serviceable during the operations.
7. Operation/Control and Indicating
The engine air-intake ice-protection system is controlled manually.
It is possible to operate the anti-ice system on the ground or in flight with the ENG 1(2) pushbutton switch on the ANTI ICE section of overhead control and indication panel 25VU.
Each ENG 1(2) pushbutton switch has two legends:
To start the engine anti-ice system, the crew must push the ENG 1(2) pushbutton switch on the ANTI ICE section of panel 25VU.
The ICE DETECTED warning message goes out of view and the indications that follows are shown:
When the icing conditions are not sensed for more than 190 seconds and the engine anti-ice system continues to operate, the ICE NOT DET message comes into view on the memo item of the WD.
The engine air-intake ice-protection system is controlled manually.
It is possible to operate the anti-ice system on the ground or in flight with the ENG 1(2) pushbutton switch on the ANTI ICE section of overhead control and indication panel 25VU.
Each ENG 1(2) pushbutton switch has two legends:
- ON: blue
- FAULT: amber.
- The ICE DETECTED warning message comes into view on the Warning Display (WD).
- The MASTER CAUT pushbutton switch legend comes on.
- The single chime operates.
To start the engine anti-ice system, the crew must push the ENG 1(2) pushbutton switch on the ANTI ICE section of panel 25VU.
The ICE DETECTED warning message goes out of view and the indications that follows are shown:
- The ENG A-ICE memo message comes into view on the WD.
- The ON legend on the ENG 1(2) pushbutton switch comes on.
- The green NAI indication comes into view on the Engine Display page (top right side of the upper ECAM DU).
When the icing conditions are not sensed for more than 190 seconds and the engine anti-ice system continues to operate, the ICE NOT DET message comes into view on the memo item of the WD.
A. Normal Operating Mode
(1) In normal aircraft operation, the FWS calculates and shows the memo messages on the lower ECAM
(a) On the overhead control and indication panel, on the ANTI ICE section when the ENG1(2) pushbutton is pushed the ON legend is on, and on the lower ECAM DU the ENG 1. ICE memo is shown.
The two solenoids are de-energized and thus the two PRSOVs are in the open and regulating position. The regulating thresholds of each PRV is set to have only the upstream valve in regulation condition in the normal "NAI ON" mode.
The two solenoids are de-energized and thus the two PRSOVs are in the open and regulating position. The regulating thresholds of each PRV is set to have only the upstream valve in regulation condition in the normal "NAI ON" mode.
(2) On the overhead control and indication panel, on the ANTI ICE section when the ENG1(2) pushbutton is released the ON legend is off, the upper valve solenoid is energized and thus the upper PRSOV is in the closed position through the EEC logic.
B. Failure Operating Mode
(1) If there is a failure of the NAI system, the EEC sends a failure message to the EIU, FWS and CFDIU. The message level is related to the failure: level 1 or 2. To make trouble shooting easier, an NAI maintenance status is shown on the ECAM: ENG X A.ICE.
Four warning messages can be shown:
Four warning messages can be shown:
- ANTI ICE ENGx VALVE OPEN (the FAULT legend is on): this is a level-2 message that shows that the two NAI valves failed open. The procedure related to this warning is to set the NAI system on to adapt the thrust decrement to the actual state of the system (in relation to the position of the pushbutton switch).
- ANTI ICE ENGx VALVE CLSD (the FAULT legend is on and NAI shown on INOPS display): this is a level-2 message that shows that one NAI valve is failed closed. The procedure related to this warning is to prevent icing conditions.
- ANTI ICE ENGx CTL FAULT (the FAULT legend is on): this is a level-2 message that shows that there is an error in the NAI control chain or a loss of monitoring. The procedure for this warning is related to the sub-title shown.
If the sub-title is ENG x A.ICE VALVE OPEN, the procedure is to set the NAI system on to adapt the thrust decrement to the actual state of the system (in relation to the position of the pushbutton-switch).
If the sub-title is ENG x A.ICE MON FAULT, the procedure is to prevent icing conditions. - ANTI ICE ENGx OVER PRESS (the FAULT legend is on): this is a level-1 message that shows that the regulation function of the two NAI valves does not operate. There is no procedure related to this message.
8. BITE
When there is a fault of the NAI system in the normal mode and the interactive mode, the BITE of the FADEC monitors the system. It sends the fault messages to the EIU, FWS and CFDIU (Ref. AMM D/O 73-21-00-00).
These BITE messages make it possible to do the TSM procedures.
When there is a fault of the NAI system in the normal mode and the interactive mode, the BITE of the FADEC monitors the system. It sends the fault messages to the EIU, FWS and CFDIU (Ref. AMM D/O 73-21-00-00).
These BITE messages make it possible to do the TSM procedures.