W DOC AIRBUS | TSM A320F

Different Total Air Temperature on the ADIRUs

TASK 34-11-00-810-865-A
Different Total Air Temperature on the ADIRUs

1. Possible Causes
2. Job Set-up Information
 A. Referenced Information
REFERENCE
DESIGNATION
AMM 30-31-34-000-002
Removal of the Probe Heat Computer (PHC)
AMM 30-31-34-400-002
Installation of the Probe Heat Computer (PHC)
AMM 31-60-00-860-001
EIS Start Procedure
AMM 34-10-00-860-002
ADIRS Start Procedure
ASM 341102
AMM 34-11-18-000-001
Removal of the TAT Sensor
AMM 34-11-18-400-001
Installation of the TAT Sensor
3. Fault Confirmation
Subtask 34-11-00-710-080-A
A. Test
Not applicable, you cannot confirm this fault on the ground.
4. Fault Isolation
Subtask 34-11-00-810-175-B ** ON A/C NOT FOR ALL
A. If the POST FLIGHT REPORT gives the maintenance message TAT SENSOR (11FP1)/ TAT SENSOR (11FP2):
  • make sure that the scoop and the choke of the TAT sensor 1 and TAT sensor 2 are not clogged or dirty.
   (1) If the scoop or the choke of one TAT sensor is damaged:
  • repair the defective TAT sensor.
   (2) If the scoop and the choke of the TAT sensors are not damaged:
  • do the EIS start procedure (lower ECAM DU, F/O ND and CAPT ND only) AMM 31-60-00-860-001,
  • do the ADIRS start procedure AMM 34-10-00-860-002,
  • write the TAT2 value (given by the ADR2) shown at the bottom of the lower ECAM DU,
  • on the SWITCHING panel 8VU, set the ECAM/ND XFR selector switch to CAPT,
  • write the TAT1 value (given by the ADR1) shown at the L bottom of the CAPT ND,
  • on the SWITCHING panel 8VU, set the AIR DATA selector switch to CAPT/3,
  • write the TAT3 value (given by the ADR3) shown at the L bottom of the lower ECAM DU.
     (a) Compare the three total air temperature values with the external ambient temperature:
       1 If the value of the TAT sensor 1 or TAT sensor 3 is different from the external ambient temperature:
       2 If the value of the TAT sensor 2 is different from the external ambient temperature :
       3 If the values are the same:
  • disconnect the electrical connectors from the TAT sensors 1 and 2
  • do a check of the resistance between pins A/B and A/C of the TAT sensors 1 and 2.
    ASM 341102
NOTE: The resistance value that follow are given for an ambient temperature of more than 0 deg. C.
         a If the resistance value of the TAT sensor 1 is more than 31 ohms (open circuit) or less than 18 ohms (short circuit):
  • replace the TAT sensor 1.
         b If the resistance value of the TAT sensor 2 is more than 31 ohms (open circuit) or less than 18 ohms (short circuit):
  • replace the TAT sensor 2.
         c If the resistance value of the TAT sensor 1 is between 18 ohms and 31 ohms:
         d If the resistance value of the TAT sensor 2 is between 18 ohms and 31 ohms:
Subtask 34-11-00-810-175-H ** ON A/C NOT FOR ALL
A. If the POST FLIGHT REPORT gives the maintenance message TAT SENSOR (11FP1)/TAT SENSOR (11FP2):
  • make sure that the scoop and the choke of the TAT sensor 1 and TAT sensor 2 are not clogged or dirty.
   (1) If the scoop or the choke of one TAT sensor is damaged:
  • repair the defective TAT sensor.
   (2) If the scoop and the choke of the TAT sensors are not damaged:
  • do the EIS start procedure (lower ECAM DU, F/O ND and CAPT ND only) AMM 31-60-00-860-001,
  • do the ADIRS start procedure AMM 34-10-00-860-002,
  • write the TAT1 value (given by the ADR1) shown at the bottom of the lower ECAM DU,
  • on the SWITCHING panel 8VU, set the ECAM/ND XFR selector switch to F/O,
  • write the TAT2 value (given by the ADR2) shown at the L bottom of the F/O ND,
  • on the SWITCHING panel 8VU, set the ECAM/ND XFR selector switch to NORM,
  • on the SWITCHING panel 8VU, set the AIR DATA selector switch to CAPT/3,
  • write the TAT3 value (given by the ADR3) shown at the L bottom of the lower ECAM DU.
     (a) Compare the three total air temperature values with the external ambient temperature:
       1 If the value of the TAT sensor 1 or TAT sensor 3 is different from the external ambient temperature:
       2 If the value of the TAT sensor 2 is different from the external ambient temperature:
       3 If the values are the same:
  • disconnect the electrical connectors from the TAT sensors 1 and 2
  • do a check of the resistance between pins A/B and A/C of the TAT sensors 1 and 2.
    ASM 341102
NOTE: The resistance value that follow are given for an ambient temperature of more than 0 deg. C.
         a If the resistance value of the TAT sensor 1 is more than 24 ohms (open circuit) or less than 18 ohms (short circuit):
  • replace the TAT sensor 1.
         b If the resistance value of the TAT sensor 2 is more than 24 ohms (open circuit) or less than 18 ohms (short circuit):
  • replace the TAT sensor 2.
         c If the resistance value of the TAT sensor 1 is between 18 ohms and 24 ohms:
         d If the resistance value of the TAT sensor 2 is between 18 ohms and 24 ohms:
5. Close-up
Subtask 34-11-00-860-050-A ** ON A/C NOT FOR ALL
A. Put the aircraft back to its initial configuration.
   (1) On the SWITCHING panel 8VU, set the ECAM/ND XFR and AIR DATA selector switches to NORM.
   (2) On the ADIR CDU, set the OFF/NAV/ATT selector switches to OFF.
   (3) On the panel 301VU, set the ND potentiometer to OFF.
   (4) On the ECAM control panel, set the LOWER DISPLAY potentiometer to OFF.
Subtask 34-11-00-860-050-C ** ON A/C NOT FOR ALL
A. Put the aircraft back to its initial configuration.
   (1) On the SWITCHING panel 8VU, set the ECAM/ND XFR and AIR DATA selector switches to NORM.
   (2) On the ADIR MSU, set the OFF/NAV/ATT selector switches to OFF.
   (3) On the CAPT LIGHTING/LOUD SPEAKER CTL panel 301VU, set the ND potentiometer to OFF.
   (4) On the ECAM control panel, set the LOWER DISPLAY potentiometer to OFF.
[Rev.8 from Aug 2018] 2026.04.04 04:38:57 UTC
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