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 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 | AIR-INTAKE ANTI-ICE VALVE 1 | 453 | 30-21-00 | ||
| 4011DN | AIR-INTAKE ANTI-ICE VALVE 2 | 453 | 30-21-00 | ||
| 4002DN | PRESS SW-ENGINE AIR INTAKE ANTI ICE, 1 | 453 | 30-21-00 | ||
| 4003DN | PRESS SW-ENGINE AIR INTAKE ANTI ICE, 2 | 453 | 30-21-00 | ||
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 HP7 engine bleed-port of the engine compressor to the engine nose cowl.
Hot air flows through a feed duct, two Pressure Regulating and Shut-Off Valves (PRSOVs) in the core zone and is discharged through nozzles into the D-duct (the compartment between the forward bulkhead and 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 from the D-duct to the external air stream through an exhaust grid.
The valves can be manually locked in the open or closed position. To control the system on the ground or in flight, you push or release the ENG pushbutton switch on the ANTI ICE section of panel 25VU.
The Electronic Engine Control (EEC) controls two solenoids. Each solenoid controls each shutoff valve. When the NAI pushbutton switch is released, the EEC operates a logic that energizes the solenoids and one of the PRSOVs closes. When the NAI pushbutton switch is pushed, the solenoids are de-energized and the PRSOVs go to a regulating position. The EEC sends an analog signal to the solenoids that control the two valves. The PRSOVs do the shutoff function in normal mode and the regulation function.
The system also prevents overheat of the air inlet skin.
Two pressure transducers are used for the system monitoring. They send the measured pressure values to the EEC. Then the EEC uses this data and other parameters to calculate the system status data (low or high pressure). The system status data is then transmitted to the Engine Interface Unit (EIU) and Flight Warning System (FWS).
Each EEC channel controls one solenoid. If necessary, through the active/active mode the EEC channel can control the two solenoids if one channel is lost.
** 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 HP7 engine bleed-port of the engine compressor to the engine nose cowl.
Hot air flows through a feed duct, two Pressure Regulating and Shut-Off Valves (PRSOVs) in the core zone and is discharged through nozzles into the D-duct (the compartment between the forward bulkhead and 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 from the D-duct to the external air stream through an exhaust grid.
The valves can be manually locked in the open or closed position. To control the system on the ground or in flight, you push or release the ENG pushbutton switch on the ANTI ICE section of panel 25VU.
The Electronic Engine Control (EEC) controls two solenoids. Each solenoid controls each shutoff valve. When the NAI pushbutton switch is released, the EEC operates a logic that energizes the solenoids and one of the PRSOVs closes. When the NAI pushbutton switch is pushed, the solenoids are de-energized and the PRSOVs go to a regulating position. The EEC sends an analog signal to the solenoids that control the two valves. The PRSOVs do the shutoff function in normal mode and the regulation function.
The system also prevents overheat of the air inlet skin.
Two pressure transducers are used for the system monitoring. They send the measured pressure values to the EEC. Then the EEC uses this data and other parameters to calculate the system status data (low or high pressure). The system status data is then transmitted to the Engine Interface Unit (EIU) and Flight Warning System (FWS).
Each EEC channel controls one solenoid. If necessary, through the active/active mode the EEC channel can control the two solenoids if one channel is lost.
4. Power Supply
There is no power supply for this system. The EEC supplies power to the solenoids and to the pressure transducers.
** ON A/C NOT FOR ALL There is no power supply for this system. The EEC supplies power to the solenoids and to the pressure transducers.
5. Interface
A. Interface with the EIU
The EIU receives inputs from the ENG 1(2) pushbutton switch on the ANTI ICE section of panel 25VU. An ARINC 429 bus (label 032 bit 22) transmits the input to the FADEC. The FADEC uses this bit to select the NAI pushbutton status.
When the ENG 1(2) pushbutton switch is pushed (ON legend on), EIU2(1) receives a ground signal and EIU1(2) receives an open signal.
When the ENG 1(2) pushbutton switch is released (ON legend off), EIU1(2) receives a ground signal and EIU2(1) receives an open signal.
The EIU transmits the signal to:
The EIU receives inputs from the ENG 1(2) pushbutton switch on the ANTI ICE section of panel 25VU. An ARINC 429 bus (label 032 bit 22) transmits the input to the FADEC. The FADEC uses this bit to select the NAI pushbutton status.
When the ENG 1(2) pushbutton switch is pushed (ON legend on), EIU2(1) receives a ground signal and EIU1(2) receives an open signal.
When the ENG 1(2) pushbutton switch is released (ON legend off), EIU1(2) receives a ground signal and EIU2(1) receives an 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 directly the NAI system. The EEC and the EIU monitor the NAI system.
The EEC supplies the NAI valve solenoids and the pressure transducers.
The EEC controls directly the NAI system. 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 channels A and B of the EEC.
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.
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 ECC controls the PRSOVs as follows:
The two PRSOVs have the pressure regulation function:
In normal operation, the two PRSOVs always regulate in cascade.
If there are no air pressure and electrical commands, the valves of the PRSOV units are fully open.
PRSOV1 is connected to the seventh stage bleed port. The PRSOVs have two Torque Motors (TM), one to control the valves fully closed
and the other to command the valves fully open.
PRSOV1 gives a stable regulated fixed pressure during all engine transient conditions. When PRSOV1 is failed open or set locked open manually, PRSOV2 gives a stable regulated fixed pressure during all engine transient conditions.
The PRSOVs are installed in the core zone and operate at a very high temperature.
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 ECC controls the PRSOVs as follows:
- If its own valve is not detected 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 own solenoid.
- If the valve controlled by the channel in control is detected 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 own solenoid.
The two PRSOVs have the pressure regulation function:
- The first PRSOV controls the anti-icing supply pressure, when the upstream pressure is sufficient to for regulation, to get a downstream of between 83 psi (5.72 bar) and 93 psi (6.41 bar).
- The second PRSOV controls the anti-icing supply pressure, when its upstream pressure is sufficient for regulation, to get an interface pressure of between 65 psi (4.48 bar) and 71 psi (4.90 bar).
In normal operation, the two PRSOVs always regulate in cascade.
If there are no air pressure and electrical commands, the valves of the PRSOV units are fully open.
PRSOV1 is connected to the seventh stage bleed port. The PRSOVs have two Torque Motors (TM), one to control the valves fully closed
and the other to command the valves fully open.
PRSOV1 gives a stable regulated fixed pressure during all engine transient conditions. When PRSOV1 is failed open or set locked open manually, PRSOV2 gives a stable regulated fixed pressure during all engine transient conditions.
B. Engine Anti-Ice Ducts
The NAI system ducting is used to transmit high-pressure compressor discharge-air to the O-ring system in the engine air-intake cowl.
The ducts are insulated in the fan compartment to keep the duct surface temperature at less than 200 deg.C (392.00 deg.F), to protect from duct burst and to prevent the ignition of flammable fluids.
The NAI system ducting has the functions that follow:
If there is a burst of the inner duct, to prevent overpressure inside the outer duct, some leakage is moved to the D-duct through holes.
The NAI system ducting is used to transmit high-pressure compressor discharge-air to the O-ring system in the engine air-intake cowl.
The ducts are insulated in the fan compartment to keep the duct surface temperature at less than 200 deg.C (392.00 deg.F), to protect from duct burst and to prevent the ignition of flammable fluids.
The NAI system ducting has the functions that follow:
- The supply duct is used to move the air from the engine part to the injection area.
- The shroud pipe is used to protect the air inlet compartment if there is a burst of the supply duct.
If there is a burst of the inner duct, to prevent overpressure inside the outer duct, some leakage is moved to the D-duct through holes.
C. Pressure Transducers
There are two NAI sensors:
The two pressure transducers in the NAI system are installed downstream of a PRSOV. They give a constant gage-pressure output. Their function is to monitor the ECAM alerts and to do trouble shooting (BITE) for the NAI system.
There are two types of transducers in this system:
To monitor the PRSOVs and to do the trouble shooting, two pressure transducers (strain gauge) are installed downstream of each PRSOV and connected to the EEC:
There are two NAI sensors:
- One NAI sensor is in the area where air is supplied to the air inlet.
- The other NAI sensor is on the aft side of the fan case.
The two pressure transducers in the NAI system are installed downstream of a PRSOV. They give a constant gage-pressure output. Their function is to monitor the ECAM alerts and to do trouble shooting (BITE) for the NAI system.
There are two types of transducers in this system:
- Single-channel pressure transducers
- Dual-channel pressure transducers.
To monitor the PRSOVs and to do the trouble shooting, two pressure transducers (strain gauge) are installed downstream of each PRSOV and connected to the EEC:
- The pressure transducer downstream of the two PRSOVs (PT2) is of dual-channel type and connected to the EEC to keep the monitoring function if there is a single failure of the EEC channel.
- The pressure transducer between the two PRSOVs (PT1) is a single channel because the pressure information is related to with PT2.
D. Swirl Nozzles
The NAI system ducting is used to transmit high-pressure compressor discharge air to the O-ring system in the engine air-intake cowl.
The O-ring system has three nozzles that mix the air and supply it to the D-duct.
It has three functions:
The NAI system ducting is used to transmit high-pressure compressor discharge air to the O-ring system in the engine air-intake cowl.
The O-ring system has three nozzles that mix the air and supply it to the D-duct.
It has three functions:
- It makes the air flow homogeneous before it goes into the D-duct.
- It prevents the unwanted effect of the hot air on the inlet and thus overheat conditions.
- It gives a one-stage jet-pump effect for better recirculation.
E. PRSOVs Activation/Deactivation of the PRSOVs
The NAI PRSOV 1(2) can be deactivated through the manual override control, in the open or closed positions.
One PROSV can be locked in the closed position (deactivated CLOSE POSITION). In this condition, no anti-ice air can flow from the engine to the inlet cowl assembly.
The other PRSOV can be locked in the open position (deactivated OPEN POSITION). In this condition, the other NAI valve must control the flow of anti-ice air to the inlet cowl assembly. Before locking the NAI PRSOV in the open position, the other NAI valve must not be in the deactivated-open condition and serviceable.
The NAI PRSOV 1(2) can be deactivated through the manual override control, in the open or closed positions.
One PROSV can be locked in the closed position (deactivated CLOSE POSITION). In this condition, no anti-ice air can flow from the engine to the inlet cowl assembly.
The other PRSOV can be locked in the open position (deactivated OPEN POSITION). In this condition, the other NAI valve must control the flow of anti-ice air to the inlet cowl assembly. Before locking the NAI PRSOV in the open position, the other NAI valve must not be in the deactivated-open condition and serviceable.
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 the overhead control and indication panel 25VU.
Each ENG 1(2) pushbutton switch has two legends:
When icing conditions are sensed and the engine anti-ice system does not operate, the warnings that follow operate:
To do this, 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 follow are given:
The PRSOV 1 regulates the upstream pressure at 88 psi (6.07 bar), then in cascade PRSOV 2 regulates the downstream pressure at 68 psi (4.69 bar).
When the icing conditions are no longer 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 EWD.
When the ANTI-ICE/ENG 1(2) pushbutton switch is released (ON legend off):
When the ANTI-ICE/ENG 1(2) pushbutton switch is pushed (ON legend on):
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 the overhead control and indication panel 25VU.
Each ENG 1(2) pushbutton switch has two legends:
- ON: blue
- FAULT: amber.
When icing conditions are sensed and the engine anti-ice system does not operate, the warnings that follow operate:
- The ICE DETECTED warning message comes into view on the EWD.
- The MASTER CAUT pushbutton-switch legend comes on.
- The single chime operates.
To do this, 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 follow are given:
- The ENG A-ICE memo message comes into view on the EWD.
- 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).
The PRSOV 1 regulates the upstream pressure at 88 psi (6.07 bar), then in cascade PRSOV 2 regulates the downstream pressure at 68 psi (4.69 bar).
When the icing conditions are no longer 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 EWD.
When the ANTI-ICE/ENG 1(2) pushbutton switch is released (ON legend off):
- The EEC channel A(B) energizes its own solenoid and the related valve closes.
- The EEC channel B(A) receives the same data but energizes its own solenoid only if there is a channel control-valve failure.
When the ANTI-ICE/ENG 1(2) pushbutton switch is pushed (ON legend on):
- The EEC channels de-energize the solenoids of each valve.
- The two PRSOV valves go to a regulating or open position (related to the upstream pressure).
A. Normal Operating Mode
In normal aircraft operation, the FWS calculates and shows the memo messages on the lower ECAM. When the ANTI-ICE/ENG pushbutton is pushed (ON legend on) the overhead panel (show only the state of the command) and the ENG A. ICE memo is shown.
In normal aircraft operation, the FWS calculates and shows the memo messages on the lower ECAM. When the ANTI-ICE/ENG pushbutton is pushed (ON legend on) the overhead panel (show only the state of the command) and the ENG A. ICE memo is shown.
B. Failure Operating Mode
If there is a failure of the NAI system, the EEC calculates a failure message and sends it to the EIU, the FWS and the CFDIU. Message class is related to the failure: class 1, 2 or SMR. To help with the trouble shooting, a maintenance status for NAI will be shown on the ECAM: ENG X A.ICE.
Five warning messages can be shown:
If there is a failure of the NAI system, the EEC calculates a failure message and sends it to the EIU, the FWS and the CFDIU. Message class is related to the failure: class 1, 2 or SMR. To help with the trouble shooting, a maintenance status for NAI will be shown on the ECAM: ENG X A.ICE.
Five warning messages can be shown:
- ANTI ICE ENGx VALVE OPEN (FAULT legend 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 pushbutton switch to the ON position.
- ANTI ICE ENGx VALVE CLSD (FAULT legend 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 avoid icing conditions.
- ANTI ICE ENGx CTL FAULT (FAULT legend 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 to set the NAI on or to prevent icing conditions.
- ANTI ICE ENGx OVER PRESS (FAULT legend 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.
- ENG X A.ICE (no cockpit indication): this is a maintenance level status that shows that there is a minor fault on the NAI system.
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.