W DOC AIRBUS | TSM A320F

Altitude or Airspeed Discrepancy between CAPT PFD - F/O PFD - STDBY/ISIS

TASK 34-13-00-810-998-A
Altitude or Airspeed Discrepancy between CAPT PFD - F/O PFD - STDBY/ISIS

1. Possible Causes
  • PROBE-L STATIC, 1 [7DA1]
  • PROBE-L STATIC, 2 [7DA2]
  • PROBE-R STATIC, 1 [8DA1]
  • PROBE-R STATIC, 2 [8DA2]
  • SENSOR-ANGLE OF ATTACK, 1 [3FP1]
  • SENSOR-ANGLE OF ATTACK, 2 [3FP2]
  • ADM-R STATIC PRESSURE [19FP4]
  • ADM-L STATIC PRESSURE [19FP5]
  • ADM-R STATIC PRESSURE [19FP6]
  • ADM-L STATIC PRESSURE [19FP7]
  • PROBE-L STATIC, 3 [7DA3]
  • PROBE-R STATIC, 3 [8DA3]
  • SENSOR-ANGLE OF ATTACK, 3 [3FP3]
  • PRESS SW-CABIN PRESS DET [14WN]
  • ADM-STBY STATIC PRESSURE [19FP8]
  • PROBE-PITOT, 1 [9DA1]
  • PROBE-PITOT, 2 [9DA2]
  • PROBE-PITOT, 3 [9DA3]
  • ADM-L TOTAL PRESSURE [19FP1]
  • ADM-R TOTAL PRESSURE [19FP2]
  • ADM-STBY TOTAL PRESSURE [19FP3]
2. Job Set-up Information
 A. Referenced Information
REFERENCE
DESIGNATION
AMM 30-31-00-710-001
Operational Test of the Probe Ice Protection
AMM 30-31-00-720-001
Functional Check of the Insulation Resistance of the Pitot Probe Heater
AMM 34-10-00-170-001
Flushing of the Principal Total Pressure Lines
AMM 34-10-00-170-002
Flushing of the Principal Static Pressure Lines
AMM 34-10-00-170-003
Draining and Flushing of Standby Pneumatic Circuits
AMM 34-11-15-000-001
Removal of the Pitot Probe
AMM 34-11-15-200-001
Inspection/Check of the Pitot Probe
AMM 34-11-15-400-001
Installation of the Pitot Probe
AMM 34-11-16-000-001
Removal of the Static Probe
AMM 34-11-16-400-002
Installation of the Static Probe
AMM 34-11-17-000-001
Removal of the Air Data Module
AMM 34-11-17-400-001
Installation of the Air Data Module
AMM 34-11-19-000-001
Removal of the Angle of Attack Sensor
AMM 34-11-19-400-001
Installation of the Angle of Attack Sensor
AMM 34-13-00-720-009
Functional Test of the Altitude and Airspeed Data (A/C without RVSM capability on ADIRU 3)
AMM 34-13-00-720-010
Functional Test of the ADM Accuracy
AMM 34-13-00-790-002
Leak Test of the Principal Static and Total Air Data System
AMM 34-21-00-720-001
Functional Test of the Standby Airspeed Indicator
AMM 34-21-00-720-002
Functional Test of the Standby Altimeter
AMM 34-21-00-790-001
Low-Range Leak Test of the Standby Pneumatic Circuits
AMM 52-73-12-000-001
Removal of the Cabin-Pressure Detection Pressure-Switch
AMM 52-73-12-400-001
Installation of the Cabin-Pressure Detection Pressure-Switch
SRM 53001101
TSM TASK 34-13-00-03
AIR DATA - TASK SUPPORTING DATA
3. Fault Confirmation
Subtask 34-13-00-720-050-A ** ON A/C NOT FOR ALL
A. Test
   (1) Check of the altitude/airspeed tolerances 34-13-00-03 TSM TASK 34-13-00-03.
     (a) If the values are in the tolerances:
  • No other maintenance step is necessary.
     (b) If the values are out of the tolerances:
       1 Do a visual check to make sure that the quick-disconnect couplings on the hose of each ADM are correctly attached to their related probes.
       2 Connect the disconnected quick-disconnect couplings if necessary.
       3 After the connection, make sure that you can see the colored ring on the quick-disconnect coupling.
       4 Pull the connectors to make sure that they are correctly connected.
       5 Do the the functional test of the altitude and airspeed data AMM 34-13-00-720-009.
4. Fault Isolation
CAUTION: IF THERE WAS AN AIRSPEED OR ALTITUDE DISCREPANCY REPORT ON THE PREVIOUS FLIGHT, DO A RESET OF THE TWO ELAC'S (OFF-ON OF THE ELAC 1 AND 2 PUSHBUTTON SWITCHES ON THE OVERHEAD PANEL) WITH THE THREE HYDRAULIC SYSTEMS DEPRESSURIZED.
Subtask 34-13-00-810-271-A ** ON A/C NOT FOR ALL
A. If the test for altitude and airspeed data is within tolerance measurements:
   (1) Do the inspection/check of the pitot probe AMM 34-11-15-200-001.
   (2) Do the functional test of the insulation resistance of the pitot probe heater AMM 30-31-00-720-001.
   (3) Do the flushing of the principal total pressure lines AMM 34-10-00-170-001.
   (4) Do the flushing of the principal static pressure lines AMM 34-10-00-170-002.
   (5) Do the draining and flushing of standby pneumatic circuits AMM 34-10-00-170-003.
   (6) Do the leak test of the principal static and total air data system AMM 34-13-00-790-002.
   (7) Do the low-range leak test of the standby pneumatic circuits AMM 34-21-00-790-001.
Subtask 34-13-00-810-273-A ** ON A/C NOT FOR ALL
B. If the test shows a different altitude value from the ADR1 (compared to the ADR2 and ADR3) or from the ADR2 (compared to the ADR1 and ADR3) :
   (1) Do the flushing of the principal static pressure lines of the Air Data Modules (ADM4 and ADM5 or ADM6 and ADM7 only) AMM 34-10-00-170-002.
   (2) Do a visual check of the static probes:
     (a) If one of these static probes is damaged, replace it:
   (3) Make sure that the small wing of the AOA 1(2) sensor is not damaged and that the mechanisms move freely.
     (a) If one of these AOA sensors is damaged, replace it:
   (4) Do the leak test of the principal static and total air data system AMM 34-13-00-790-002.
   (5) Do the functional test of the ADM accuracy for ADM4, ADM5, ADM6 and ADM7 only AMM 34-13-00-720-010.
     (a) If one value read is different, replace the defective ADM:
     (b) If the pressure values are correct:
Subtask 34-13-00-810-274-A ** ON A/C NOT FOR ALL
C. If the test shows a different altitude value from the ADR3 (compared to the ADR1 and the ADR2):
   (1) Do the draining and flushing of standby pneumatic circuits AMM 34-10-00-170-003.
   (2) Do a visual check of the static probes:
     (a) If one of these static probes is damaged, replace it:
   (3) Make sure that the small wing of the AOA3 sensor is not damaged and that the mechanisms move freely.
     (a) If the SENSOR-ANGLE OF ATTACK, 3 [3FP3] is damaged, replace it AMM 34-11-19-000-001 and AMM 34-11-19-400-001.
   (4) Do the low-range leak test of the standby pneumatic circuits AMM 34-21-00-790-001.
   (5) Do the functional test of the standby altimeter AMM 34-21-00-720-002.
   (6) Do the functional test of the ADM accuracy for ADM8 only AMM 34-13-00-720-010.
     (a) If the value read is different:
       1 Replace the PRESS SW-CABIN PRESS DET [14WN] AMM 52-73-12-000-001 and AMM 52-73-12-400-001.
       2 If the fault continues:
     (b) If the pressure values are correct:
Subtask 34-13-00-810-275-A ** ON A/C NOT FOR ALL
D. If the test shows a different airspeed value from the ADR1 (compared to the ADR2 and the ADR3), from the ADR2 (compared to the ADR1 and the ADR3) or from the ADR3 (compared to the ADR1 and the ADR2):
   (1) Do a visual check of the pitot probes:
     (a) If one of these pitot probes is damaged, replace it:
   (2) Do the flushing of the principal total pressure lines of the Air Data Modules (ADM1 and ADM2 only) AMM 34-10-00-170-001.
   (3) Do the draining and flushing of standby total pressure lines AMM 34-10-00-170-003.
   (4) Do the leak test of the principal static and total air data system AMM 34-13-00-790-002.
   (5) Do the low-range leak test of the standby pneumatic circuits AMM 34-21-00-790-001.
   (6) Do the functional test of the standby airspeed indicator AMM 34-21-00-720-001.
   (7) Do the operational test of the probe ice protection AMM 30-31-00-710-001.
     (a) If the test gives a maintenance message, do the trouble shooting procedure related to the maintenance message.
   (8) Do the functional test of the insulation resistance of the pitot probe heater AMM 30-31-00-720-001.
   (9) Do the functional test of the ADM accuracy for ADM1, ADM2 and ADM3 only AMM 34-13-00-720-010.
     (a) If one value read is different:
Subtask 34-13-00-810-276-A ** ON A/C NOT FOR ALL
E. If the fault continues:
  • Do a check to make sure that there are no impacts on the fuselage around the AOA and the static probes SRM 53001101.
   (1) If there is no impact:
Subtask 34-13-00-720-051-A ** ON A/C NOT FOR ALL
F. Do the test given in Para. 3.
[Rev.8 from Aug 2018] 2026.04.04 04:32:32 UTC
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