W DOC AIRBUS | AMM A320F

Functional Test of the Standby Altimeter

TASK 34-21-00-720-002-A
Functional Test of the Standby Altimeter

ZONE: 120
ZONE: 210
1. Reason for the Job
To make sure that the standby altimeter and the metric altimeter operate correctly with information from the ground pressure generator.
2. Job Set-up Information
 A. Fixtures, Tools, Test and Support Equipment
REFERENCE
QTY
DESIGNATION
No specific
AR
SAFETY CLIP - CIRCUIT BREAKER
No specific
AR
TAPE - ADHESIVE
ALT34100001
1
PITOT AND STATIC TEST SET
 B. Work Zones and Access Panels
ZONE/ACCESS
ZONE DESCRIPTION
120
AVIONICS COMPARTMENT
210
CKPT,FWD COMPT BHD TO FLT COMPT BULKHEAD
 C. Referenced Information
REFERENCE
DESIGNATION
TASK 12-24-34-600-001-A
Bleeding of the Standby Air Data System
TASK 24-41-00-861-002-A
Energize the Aircraft Electrical Circuits from the External Power
TASK 24-41-00-861-002-A-01
Energize the Aircraft Electrical Circuits from the APU
TASK 24-41-00-861-002-A-02
Energize the Aircraft Electrical Circuits from Engine 1(2)
TASK 24-41-00-862-002-A
De-energize the Aircraft Electrical Circuits Supplied from the External Power
TASK 24-41-00-862-002-A-01
De-energize the Aircraft Electrical Circuits Supplied from the APU
TASK 24-41-00-862-002-A-02
De-energize the Aircraft Electrical Circuits Supplied from the Engine 1(2)
TASK 32-00-00-860-001-A
Flight Configuration Precautions with Electrical Power
TASK 32-00-00-860-001-A-01
Flight Configuration Precautions without Electrical Power
TASK 32-00-00-860-002-A
Ground Configuration after Flight Configuration with Electrical Power
TASK 32-00-00-860-002-A-01
Ground Configuration after Flight Configuration without Electrical Power
3. Job Set-up
WARNING: MAKE SURE THAT ALL THE CIRCUITS IN MAINTENANCE ARE ISOLATED BEFORE YOU SUPPLY ELECTRICAL POWER TO THE AIRCRAFT. UNWANTED ELECTRICAL POWER CAN BE DANGEROUS.
Subtask 34-21-00-860-063-A ** ON A/C NOT FOR ALL
A. Aircraft Maintenance Configuration
   (1) Energize the aircraft electrical circuits
(Ref. AMM TASK 24-41-00-861-002).
   (2) Take the applicable safety precautions before you open the LGCIU circuit breakers (Ref. AMM TASK 32-00-00-860-001)
   (3) Drain the standby air-data system (Ref. AMM TASK 12-24-34-600-001).
Subtask 34-21-00-865-053-A ** ON A/C NOT FOR ALL
WARNING: OPEN CIRCUIT BREAKER 7XE. THIS WILL PREVENT A POSSIBLE DEPLOYMENT OF THE RAT IF THE MAIN AC BUSBARS 1XP AND 2XP BECOME ISOLATED.
B. Open, safety and tag this(these) circuit breaker(s):
PANELDESIGNATIONFINLOCATION
** ON A/C NOT FOR ALL
49VUL/G/LGCIU/SYS1/NORM1GAC09
49VUANTI ICE/PROBES/AOA/14DA1D04
49VUANTI ICE/PROBES/PITOT/13DA1D02
105VUELEC/CSM/G /EV AUTO/SPLY7XEC01
121VUHYDRAULIC/LGCIU/SYS22GAQ35
121VUHYDRAULIC/LGCIU/SYS1/GRND SPLY52GAQ34
122VUANTI ICE/PROBES/2/TAT1DA2Y15
122VUANTI ICE/PROBES/2/PITOT3DA2Y14
122VUANTI ICE/PROBES/2/AOA4DA2Y13
122VUANTI ICE/PROBES/2/STATIC5DA2Y11
122VUANTI ICE/PROBES/3/PITOT3DA3Z16
122VUANTI ICE/PROBES/3/AOA4DA3Z15
122VUANTI ICE/PROBES/3/STATIC5DA3Z14
122VUANTI ICE/PROBES/1/STATIC5DA1Z13
122VUANTI ICE/PROBES/1/TAT1DA1Z12
Subtask 34-21-00-865-054-A ** ON A/C NOT FOR ALL
C. Make sure that this(these) circuit breaker(s) is(are) closed:
PANELDESIGNATIONFINLOCATION
** ON A/C NOT FOR ALL
49VUNAV/STBY/ALTM16FNF14
Subtask 34-21-00-860-052-A ** ON A/C NOT FOR ALL
D. Aircraft Maintenance Configuration
   (1) Remove the protective covers from the left and right static probes 7DA3 and 8DA3 of the standby system.
   (2) Remove the protective cover from the standby pitot probe of the standby system.
   (3) Connect the ALT34100001 PITOT AND STATIC TEST SET to the left or right standby static-probe with the ADAPTER STATIC PROBE.
   (4) Connect the ALT34100001 PITOT AND STATIC TEST SET to the standby pitot probe with the ADAPTER PITOT PROBE.
CAUTION: WHEN YOU SEAL THE DRAIN HOLE IN THE PITOT PROBE, DO NOT SEAL THE HOLE DIRECTLY WITH THE COLORED ADHESIVE TAPE. ALWAYS PUT A PIECE OF PLASTIC ON THE HOLE FIRST AND USE THE COLORED ADHESIVE TAPE TO ATTACH THE PLASTIC. IF YOU SEAL THE DRAIN HOLE DIRECTLY WITH THE ADHESIVE TAPE, THERE IS A RISK THAT SOME OF THE ADHESIVE WILL STAY ON THE HOLE AND COLLECT PARTICLES. THIS CAN SUBSEQUENTLY CAUSE BLOCKAGE OF THE HOLE AND THUS INCORRECT OPERATION OF THE PROBE.
   (5) Seal the drain holes of the pitot probe with the piece of plastic and the TAPE - ADHESIVE very bright color.
   (6) Seal the opposite standby static-probe with the piece of plastic and with the ADAPTER STATIC COVER from the ADAPTER STATIC PROBE.
   (7) Start the ground pressure generator and set a static pressure of 1013 mb.
4. Procedure
CAUTION: TO PREVENT DAMAGE TO INSTRUMENTS, OBEY THESE PRECAUTIONS WHEN YOU DO THE TEST:
  • THE PRESSURES SET MUST NOT BE MORE THAN 1050 hPa (31 in Hg) OR LESS THAN 115 hPa (3.39 in Hg)
  • CHANGES IN STATIC AND TOTAL PRESSURES MUST NOT BE MORE THAN 6000 FEET/MINUTE
  • DO NOT SUDDENLY OPEN LINES TO AMBIENT AIR WHILE THE PRESSURE GENERATOR IS CONNECTED.
CAUTION: THE TOTAL PRESSURE IN THE PITOT SYSTEM MUST NEVER BE LESS THAN THE STATIC PRESSURE. THE DIFFERENCE BETWEEN THE PITOT AND THE STATIC PRESSURE CIRCUITS MUST NEVER BE MORE THAN 368 hPa (10.86 in Hg).
Subtask 34-21-00-720-051-B ** ON A/C NOT FOR ALL
A. Test of the Standby and Metric Altimeters
ACTION
RESULT
1.On the standby altimeter and the metric altimeter, set a barometric pressure of 1013 hPa.

2.On the ground pressure generator:
  • Set a static pressure of 977.1 hPa (1000 ft or 305 m).
Make sure that the standby altimeter indicates 1000 ft (+ or - 20 ft) and the metric altimeter indicates 305 m (+ or - 7 m).
  • Set a static pressure of 908.1 hPa (3000 ft or 915 m).
  • Make sure that the standby altimeter indicates 3000 ft (+ or - 30 ft) and the metric altimeter indicates 915 m (+ or - 10 m).
  • Set a static pressure of 843 hPa (5000 ft or 1525 m)
  • make sure that the standby altimeter indicates 5000 ft (+ or - 40 ft) and the metric altimeter indicates 1525 m (+ or - 13 m).
  • Set a static pressure of 571.8 hPa (15,000 ft or 4570 m).
  • Make sure that the standby altimeter indicates 15,000 ft (+ or - 110 ft) and the metric altimeter indicates 4570 m (+ or - 34 m).
  • Set a static pressure of 314.8 hPa (29,000 ft or 8840 m).
  • Make sure that the standby altimeter indicates 29,000 ft (+ or - 190 ft) and the metric altimeter indicates 8840 m (+ or - 60 m).
  • Slowly decrease the pressure until you get atmospheric pressure.

3.Stop the ground pressure generator.

5. Close-up
Subtask 34-21-00-860-054-A ** ON A/C NOT FOR ALL
A. Put the aircraft back to its initial configuration.
   (1) Disconnect the ALT34100001 PITOT AND STATIC TEST SET.
   (2) Remove the adaptors from the standby static probes and the standby pitot probe.
   (3) Remove the cover from the opposite standby static probe.
   (4) Remove the piece of plastic from the opposite standby static probe.
   (5) Remove the piece of plastic and colored adhesive tape from the drain holes of the standby pitot probe.
   (6) Install the protective covers on the static probes.
Subtask 34-21-00-865-055-A ** ON A/C NOT FOR ALL
B. Remove the safety clip(s) and the tag(s) and close this(these) circuit breaker(s):
PANELDESIGNATIONFINLOCATION
** ON A/C NOT FOR ALL
49VUL/G/LGCIU/SYS1/NORM1GAC09
49VUANTI ICE/PROBES/AOA/14DA1D04
49VUANTI ICE/PROBES/PITOT/13DA1D02
105VUELEC/CSM/G /EV AUTO/SPLY7XEC01
121VUHYDRAULIC/LGCIU/SYS22GAQ35
121VUHYDRAULIC/LGCIU/SYS1/GRND SPLY52GAQ34
122VUANTI ICE/PROBES/2/TAT1DA2Y15
122VUANTI ICE/PROBES/2/PITOT3DA2Y14
122VUANTI ICE/PROBES/2/AOA4DA2Y13
122VUANTI ICE/PROBES/2/STATIC5DA2Y11
122VUANTI ICE/PROBES/3/PITOT3DA3Z16
122VUANTI ICE/PROBES/3/AOA4DA3Z15
122VUANTI ICE/PROBES/3/STATIC5DA3Z14
122VUANTI ICE/PROBES/1/STATIC5DA1Z13
122VUANTI ICE/PROBES/1/TAT1DA1Z12
Subtask 34-21-00-860-064-A ** ON A/C NOT FOR ALL
C. Put the aircraft back to its initial configuration.
   (1) Close the LGCIU circuit breakers and put the aircraft back to its inertial configuration (Ref. AMM TASK 32-00-00-860-002).
   (2) De-energize the aircraft electrical circuits
(Ref. AMM TASK 24-41-00-862-002).
[Rev.10 from 2021] 2026.04.02 06:23:13 UTC
"WTRUIB" 2025