W DOC AIRBUS | AMM A320F

PROBE ICE PROTECTION - DESCRIPTION AND OPERATION

** ON A/C NOT FOR ALL
1. General
The air data system (Ref. AMM D/O 34-10-00-00) includes several probes and sensors (pitot and static probes, angle of attack and total air temperature (TAT) sensors) located on the fuselage in zones particularly exposed to ice.
An electrical heating system integral with each probe operates permanently to maintain probe efficiency. Permanent monitoring of the probes is ensured.
Warning is provided to indicate heating malfunction of each probe.
The air data system comprises three independent detection channels:
  • 1 (Captain),
  • 2 (First Officer),
  • 3 (Standby).
** ON A/C NOT FOR ALL
2. Component Location
F Probe Ice Protection - Component Location
FIN FUNCTIONAL
DESIGNATION		 PANEL ZONE ACCESS
DOOR		 ATA REF
** ON A/C ALL
6DA1 PHC-1 121 30-31-34
6DA2 PHC-2 122 30-31-34
6DA3 PHC-3 121 30-31-34
7DA1 PROBE-L STATIC, 1 127 34-11-16
7DA2 PROBE-L STATIC, 2 127 34-11-16
7DA3 PROBE-L STATIC, 3 121 34-11-16
8DA1 PROBE-R STATIC, 1 128 34-11-16
8DA2 PROBE-R STATIC, 2 128 34-11-16
8DA3 PROBE-R STATIC, 3 122 34-11-16
9DA1 PROBE-PITOT, 1 125 34-11-15
9DA2 PROBE-PITOT, 2 126 34-11-15
9DA3 PROBE-PITOT, 3 125 34-11-15
** ON A/C NOT FOR ALL
3. System Description
A. Probe Ice Protection
Electrical heating of the probes prevents ice accretion on the probes of the air data system:
  • pitot probes,
  • static probes,
  • angle of attack sensors,
  • TAT sensors.
The TAT sensors are not heated on the ground.
The ice protection system of the probes is arranged in three independent channels (1, 2 and 3).
B. PHC
(1) The PHC controls and monitors heating of the probes given below:
  • one pitot probe,
  • one AOA sensor,
  • two static probes,
  • one TAT sensor.
(2) There are three PHCs, one per probe channel:
  • PHC 1,
  • PHC 2,
  • PHC 3 (channel 3 does not include the TAT sensor).
(3) Electrical connections
F Ice Protection of Probes 1 - Schematic
F Ice Protection of Probes 2 - Schematic
F Ice Protection of Probes 3 - Schematic
** ON A/C NOT FOR ALL
4. Power Supply
F Ice Protection of Probes 1 - Schematic
F Ice Protection of Probes 2 - Schematic
F Ice Protection of Probes 3 - Schematic
The supply and protection of the components and functions is given below:
-------------------------------------------------------------------------------
!COMPONENT/FUNCTION ! CIRCUIT ! BUS !
! ! BREAKER ! !
!-------------------------------------------------!--------------!------------!
! ! Supply of TAT sensor heating ! 1DA1 ! 101XP-A !
! !----------------------------------!--------------!------------!
! ! Supply of PHC ! 2DA1 ! 401PP !
! !----------------------------------!--------------!------------!
! PROBES ! Supply of pitot probe heating ! 3DA1 ! 401XP-B !
! 1 !----------------------------------!--------------!------------!
! ! Supply of angle of attack sensor ! 4DA1 ! 801XP !
! ! heating ! ! !
! !----------------------------------!--------------!------------!
! ! Supply of static probe heating ! 5DA1 ! 101PP !
!-------------------------------------------------!--------------!------------!
! ! Supply of TAT sensor heating ! 1DA2 ! 202XP-C !
! !----------------------------------!--------------!------------!
! ! Supply of PHC ! 2DA2 ! 206PP !
! !----------------------------------!--------------!------------!
! PROBES ! Supply of pitot probe heating ! 3DA2 ! 202XP-B !
! 2 !----------------------------------!--------------!------------!
! ! Supply of angle of attack sensor ! 4DA2 ! 202XP-B !
! ! heating ! ! !
! !----------------------------------!--------------!------------!
! ! Supply of static probe heating ! 5DA2 ! 206PP !
!-------------------------------------------------!--------------!------------!
! ! Supply of PHC ! 2DA3 ! 101PP !
! !----------------------------------!--------------!------------!
! ! Supply of pitot probe heating ! 3DA3 ! 103XP-C !
! PROBES !----------------------------------!--------------!------------!
! 3 ! Supply of angle of attack sensor ! 4DA3 ! 103XP-C !
! ! heating ! ! !
! !----------------------------------!--------------!------------!
! ! Supply of static probe heating ! 5DA3 ! 103PP !
-------------------------------------------------------------------------------

** ON A/C NOT FOR ALL
5. Interface
F Ice Protection of Probes 1 - Schematic
F Ice Protection of Probes 2 - Schematic
F Ice Protection of Probes 3 - Schematic
The ice protection system of the probes is associated with:
  • the Engine Interface Unit (EIU) (Functional Interfaces),
  • the shock absorbers of the landing gear,
  • the Centralized Fault Display Interface Unit (CFDIU),
to control and select the heating mode of the probes.
** ON A/C NOT FOR ALL
6. Component Description
A. Probes FIN: 7-DA-1 FIN: 7-DA-2 FIN: 7-DA-3 FIN: 8-DA-1 FIN: 8-DA-2 FIN: 8-DA-3 FIN: 9-DA-1 FIN: 9-DA-2 FIN: 9-DA-3
(1) Pitot probe
F Probe Ice Protection - Pitot Probe ** ON A/C NOT FOR ALL
Power is applied to:
  • the main portion of the detection tube of total pressure,
  • the inner surface of the cavity located in the mast.
Power is supplied with 115 VAC nominal.
Heating of the pitot probe is reduced on the ground.
The PHC automatically controls the changeover of the probe heating level.
(2) Static probe
F Probe Ice Protection - Static Probe ** ON A/C NOT FOR ALL
Power is applied to the periphery of the orifice.
Power is supplied with 28VDC nominal.
(3) AOA sensor
F Probe Ice Protection - Angle of Attack Sensor ** ON A/C NOT FOR ALL
The AOA sensor is of the vane type.
Power is applied to the internal solid-state heaters of the vane.
Power is supplied with 115VAC nominal.
(4) TAT sensor
F Probe Ice Protection - TAT Sensor ** ON A/C NOT FOR ALL
Power is applied to the leading edge of the air inlet.
Power is supplied with 115VAC nominal.
Heating is cut off on the ground. The PHC automatically controls this changeover.
(5) Pitot probe
F Probe Ice Protection - Pitot Probe ** ON A/C NOT FOR ALL
Power is applied to:
  • the main portion of the detection tube of total pressure,
  • the inner surface of the cavity located in the mast.
Power is supplied with 115 VAC nominal.
Heating of the pitot probe is reduced on the ground.
The PHC automatically controls the changeover of the probe heating level.
(6) Static probe
F Probe Ice Protection - Static Probe ** ON A/C NOT FOR ALL
Power is applied to the periphery of the orifice.
Power is supplied with 28VDC nominal.
(7) AOA sensor
F Probe Ice Protection - Angle of Attack Sensor ** ON A/C NOT FOR ALL
The AOA sensor is of the vane type.
Power is applied to the internal solid-state heaters of the vane.
Power is supplied with 115VAC nominal.
(8) TAT sensor
F Probe Ice Protection - TAT Sensor ** ON A/C NOT FOR ALL
The aircraft has two total air-temperature sensors with two sensing elements each. The resistance values of the sensing element sensors can change. Each sensor has an air suction system, supplied with compressed air that gives better measurement precision, usually on ground. This system pulls ambient air by and through the sensing element.
The TAT sensor 1 is connected to the ADR portion of ADIRUs 1 and 3, the TAT sensor 2 is connected to the ADR portion of ADIRU 2.
The TAT sensors are set at 2.33 m from the A/C nose and at 0.60 m from the aircraft axis below the fuselage. The TAT sensor 1 is on the left side and the TAT sensor 2 on the right side.
The air flow gets into the scoop of the sensor and goes through a calibrated choke. Then it flows over the hermetically sealed platinum resistance sensing-element where the temperature is measured.
The choke in the element tube controls the speed of the flow over the element.
The ADR portion operates with 500 ohms (at 0 deg. C) temperature sensor unit that agrees with the basic Callender - Van Dusen equation.
A network of precision resistors makes the precision of the sensor better.
This technique is identified by the term Precision Calibration Interchangeability (PCI).
The probe heating system manages the heating of these sensors with 115VAC.
The heating element must not be energized on the ground.
The heating element is installed in the scoop and strut and prevents ice in the probe in icing conditions.
B. PHC FIN: 6-DA-1 FIN: 6-DA-2 FIN: 6-DA-3
F Ice Protection of Probes 1 - Schematic
F Ice Protection of Probes 2 - Schematic
F Ice Protection of Probes 3 - Schematic
(1) The PHCs are installed in the avionics compartment.
The PHC controls and monitors heating of the probes given below:
  • one pitot probe,
  • two static probes,
  • one AOA sensor,
  • one TAT sensor.
The PHC identifies and memorizes the failures.
There are three PHCs, one per probe channel:
  • PHC 1,
  • PHC 2,
  • PHC 3 (Channel 3 does not include the TAT sensor).
    The PHC is supplied with 28VDC. Three ports enable the PHC position to be selected.
    The PHC controls the temperature of the probes and sensors according to acquisition of discrete aircraft information. This function is achieved by a hardware logic device independent of the software.
(2) Input - Output
The PHC acquires 10 discrete inputs of standard type (ground/open):
  • 4 from the Landing Gear Control and Interface Unit (LGCIU), 2 ground/flight information, and 2 from the LGCIU validity,
  • 2 from the EIVMU, engine running or not,
  • 1 for the ON control,
  • 1 from the CFDS for the maintenance test,
  • 1 for the reset function,
  • 1 for the low speed warning (V greater than 50 kts).
The PHC generates 5 discrete outputs to the Flight Warning Computer (FWC) via the Air Data/Inertial Reference Unit (ADIRU):
  • 1 discrete output directly to the System Data Acquisition Concentrator (SDAC),
  • 1 for the indication of TAT sensor heating or not,
  • 1 for the indication of the pitot probe heating fault,
  • 1 for the indication of the L static probe heating fault,
  • 1 for the indication of the R static probe heating fault,
  • 1 for the indication of the AOA sensor heating fault,
  • heating availability directly to the SDAC.
The PHC transmits one ARINC 429 low-speed data bus for fault message to the CFDS.
** ON A/C NOT FOR ALL
7. Operation/Control and Indicating
F Fault of Pitot Probes 1
F Fault of Pitot Probes 2
F Fault of Pitot Probes 3
F Fault of Probes 1 (2, 3) Heat
A. Operation
The conditions:
  • ENG 1 RUNNING
  • or ENG 2 RUNNING
  • or PROBE/WINDOW HEAT pushbutton switch in ON configuration (anticipated heating) cause heating of the probes given below:
    . static probe,
    . AOA sensor,
    . pitot probe. There are two heating levels for the pitot probe:
    * on the ground: half-wave heating,
    * in flight: full-wave heating.
    The input receives the heating command.
    . TAT sensor in flight.

B. Control and indicating
F Probe Ice Protection-Schematic
(1) Monitoring
The PHC monitors heating of the static probes, AOA sensor, pitot probes and TAT sensor.
Current detection with a preset threshold is provided for monitoring purposes.
Low heating or overcurrent or heating loss or discrepancy between the ground and flight information sent by the LGCIUs triggers a warning.
Monitoring of the TAT sensors is inhibited on the ground.
A monitoring system activates a warning when heating is incorrect. Warning is triggered as follows:
(a) For pitot probe
  • in flight when the current I is lower than 0.9 A or greater than 6 A,
  • on ground when the current I is lower than 0.4 A or greater than 4 A.
(b) For TAT sensor
When the current I is lower than 0.8 A or greater than 4 A.
(c) For AOA sensor
When the current I is lower than 0.12 A or greater than 5 A.
(d) For L and R static probes
When the current is lower than 1.3 A or greater than 4 A.
The PHC serves to:
  • identify the faulty element(s),
  • memorize the faulty element.
(2) Indication
F Fault of Probes 1 (2, 3) Heat
F Fault of Pitot Probes 3
F Fault of Pitot Probes 2
F Fault of Pitot Probes 1
The PHC continuously emits signals via the ARINC 429 bus (low speed).
A discrete output (one per probe) informs the ADIRU of associated probe channel of the heating fault.
Then, the ADIRU informs the Flight Warning Computer (FWC).
** ON A/C NOT FOR ALL
8. BITE Test
A. Maintenance test
The PHC performs a test initiated either by power up or by the CFDS.
The purpose of the test is to check:
  • Internal circuits:
    . CPU RAM, EPROM
    . acquisition of discrete inputs
    . discrete outputs
    . power outputs for CFDS test only.

  • External circuits:
    . integrity of probe heaters (CFDS test only).

B. Power-up Test Initialization and Cockpit Repercussions
(1) Conditions of power-up test initialization
  • de-energization time of computer: 3 s.
  • A/C configuration:
    - whatever the A/C configuration on ground.
(2) Progress of power-up tests
  • Duration: 9 s.
NOTE: In case at least one engine is in operation, duration: 14 s.
  • Cockpit repercussions (ECAM warning, audio warning, pushbutton switch flashing, if any):
    - none
(3) Results of power-up tests
(cockpit repercussions, if any, in case of tests passed/tests failed)
(a) Tests passed:
  • none.
(b) Tests failed:
  • ECAM warning: (XX: CAPT, F/O or STBY)
    - ANTI-ICE XX PITOT
    - ANTI-ICE XX TAT
    - ANTI-ICE XX AOA
    - ANTI-ICE XX L STATIC
    - ANTI-ICE XX R STATIC
    - ANTI-ICE XX PROBES.
NOTE: - The PHC 1 controls the Captain and left systems.
- The PHC 2 controls the First Officer and right systems.
- The PHC 3 controls the Standby systems.
[Rev.10 from 2021] 2026.04.01 12:34:18 UTC
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