DOC AIRBUS | AMM A320FInstallation of the Integrated Standby Instrument System (ISIS) Indicator
TASK 34-22-25-400-001-A
Installation of the Integrated Standby Instrument System (ISIS) Indicator
1. Reason for the Job
Self explanatory
2. Job Set-up Information
A. Work Zones and Access Panels
B. Referenced Information
3. Job Set-up
Subtask 34-22-25-865-059-A ** ON A/C NOT FOR ALL
Subtask 34-22-25-420-051-A ** ON A/C NOT FOR ALL
Subtask 34-22-25-410-050-A ** ON A/C NOT FOR ALL
[Rev.10 from 2021]
2026.04.01 01:00:00 UTC
Installation of the Integrated Standby Instrument System (ISIS) Indicator
1. Reason for the Job
Self explanatory
2. Job Set-up Information
A. Work Zones and Access Panels
| ZONE/ACCESS | ZONE DESCRIPTION |
|---|---|
| 211 | COCKPIT |
| REFERENCE | DESIGNATION |
|---|---|
| TASK 25-13-41-000-002-A | Removal of the Sidewall Panels |
| TASK 25-13-41-400-002-A | Installation of the Sidewall Panels |
| TASK 33-13-00-710-001-A | Operational Test of the Instrument and Panel Integral-Lighting |
| TASK 34-22-25-740-001-A | BITE Test of the Integrated Standby Instrument System (ISIS) Indicator with the Pushbutton Switches on the Face of the Indicator |
ISIS IndicatorSubtask 34-22-25-865-059-A ** ON A/C NOT FOR ALL
A. Make sure that this(these) circuit breaker(s) is(are) open, safetied and tagged:
Subtask 34-22-25-010-053-A ** ON A/C NOT FOR ALL | PANEL | DESIGNATION | FIN | LOCATION |
|---|---|---|---|
| ** ON A/C NOT FOR ALL | |||
| 49VU | NAV/STBY/INST | 5FN | F12 |
| 105VU | NAV/STBY/INST/BAT | 23FN | J01 |
| 122VU | LIGHTING/INSTL LT/MAIN INST/PNL AND/PED | 4LF | Y04 |
B. Remove the sidewall panel 211LW (Ref. AMM TASK 25-13-41-000-002).
(1) Make sure that the thermoformed cover is removed from the center instrument panel.
Subtask 34-22-25-860-073-A ** ON A/C NOT FOR ALL (1) Make sure that the thermoformed cover is removed from the center instrument panel.
C. Aircraft Maintenance Configuration
4. ProcedureNOTE: In this procedure, the screws are identified as the adjusting screws and the mounting screws.
(1) Before you install the ISIS indicator, make sure that the two mounting screws that attach the clamp to the aircraft structure are installed as follows: - The adjusting screws (3) are installed on the top right and bottom left corners of the ISIS indicator housing.
- The mounting screws are installed on the top left and bottom right corners of the ISIS indicator housing.
- One in the top left corner, and
- The other in the bottom right corner.
Subtask 34-22-25-420-051-A ** ON A/C NOT FOR ALL
A. Installation of the ISIS Indicator (22FN)
(1) Clean the component interfaces and the adjacent area.
(2) Do an inspection of the component interfaces and the adjacent area.
(3) Remove the PLUG - BLANKING from the connectors (5) and the quick-disconnect couplings (2).
(4) Connect the quick-disconnect couplings (2) of the pressure lines to the related connectors (5) of the ISIS indicator (1)
(5) Make sure that you can see the color ring on the quick-disconnect couplings (2).
(6) Pull the quick-disconnect couplings (2) to make sure that they are correctly attached.
(7) Make sure that the quick-disconnect couplings (2) are correctly engaged (the pin on the quick-disconnect male part is fully engaged into the groove of the quick-disconnect female part)
(a) Refer to the table that follows to know if you must do the two checks of the quick-disconnect couplings (2) and/or the leak test:
(8) Remove the CAP - BLANKING from the electrical connectors (4) and (6).
(9) Make sure that all the electrical connections are clean and in the correct condition.
(10) Connect the electrical connector (4) to the ISIS indicator (1).
(11) Install the ISIS indicator (1) in its housing.
(12) Look behind the ISIS indicator (1) and make sure that the position of the flexible hoses (static and total pressure lines) is satisfactory (there are no crushing, kinks, creases or folds in the flexible hoses).
(13) Install the adjusting screws (3). Do not tighten at this step.
Subtask 34-22-25-865-060-A ** ON A/C NOT FOR ALL (1) Clean the component interfaces and the adjacent area.
(2) Do an inspection of the component interfaces and the adjacent area.
(3) Remove the PLUG - BLANKING from the connectors (5) and the quick-disconnect couplings (2).
(4) Connect the quick-disconnect couplings (2) of the pressure lines to the related connectors (5) of the ISIS indicator (1)
(5) Make sure that you can see the color ring on the quick-disconnect couplings (2).
(6) Pull the quick-disconnect couplings (2) to make sure that they are correctly attached.
(7) Make sure that the quick-disconnect couplings (2) are correctly engaged (the pin on the quick-disconnect male part is fully engaged into the groove of the quick-disconnect female part)
(a) Refer to the table that follows to know if you must do the two checks of the quick-disconnect couplings (2) and/or the leak test:
| Condition | Two Checks of the Quick-Disconnect Couplings | Leak Test |
| ISIS installation | No | No |
(9) Make sure that all the electrical connections are clean and in the correct condition.
(10) Connect the electrical connector (4) to the ISIS indicator (1).
(11) Install the ISIS indicator (1) in its housing.
(12) Look behind the ISIS indicator (1) and make sure that the position of the flexible hoses (static and total pressure lines) is satisfactory (there are no crushing, kinks, creases or folds in the flexible hoses).
(13) Install the adjusting screws (3). Do not tighten at this step.
B. Remove the safety clip(s) and the tag(s) and close this(these) circuit breaker(s):
Subtask 34-22-25-720-052-A ** ON A/C NOT FOR ALL | PANEL | DESIGNATION | FIN | LOCATION |
|---|---|---|---|
| ** ON A/C NOT FOR ALL | |||
| 49VU | NAV/STBY/INST | 5FN | F12 |
| 105VU | NAV/STBY/INST/BAT | 23FN | J01 |
| 122VU | LIGHTING/INSTL LT/MAIN INST/PNL AND/PED | 4LF | Y04 |
C. Get access to the ISIS maintenance menu:
(1) Boresighting function available: go to Para. 4.E.
(2) Boresighting function not available: go to Para. 4.D.
Subtask 34-22-25-710-050-A ** ON A/C NOT FOR ALL (1) Boresighting function available: go to Para. 4.E.
(2) Boresighting function not available: go to Para. 4.D.
D. Test of the ISIS Indicator (without the Boresighting Function)
(1) Make sure that the indications (roll, pitch and lateral acceleration) on the ISIS indicator are the same as the indications on the CAPT (F/O) PFD.
(2) Make sure that the indications on the ISIS indicator are in the limits that follow:
(4) Do the operational test of the instrument and panel integral-lighting (Ref. AMM TASK 33-13-00-710-001).
(5) Do the BITE test of the ISIS indicator (Ref. AMM TASK 34-22-25-740-001).
Subtask 34-22-25-710-054-A ** ON A/C NOT FOR ALL (1) Make sure that the indications (roll, pitch and lateral acceleration) on the ISIS indicator are the same as the indications on the CAPT (F/O) PFD.
(2) Make sure that the indications on the ISIS indicator are in the limits that follow:
- Roll: Less than 2.5 degrees (equivalent to one-quarter of a roll graduation) (item A)
- Pitch: Less than 1.25 degrees (equivalent to half of a pitch graduation) (item B)
- Lateral Acceleration: Less than 1.3 mm (item C).
(4) Do the operational test of the instrument and panel integral-lighting (Ref. AMM TASK 33-13-00-710-001).
(5) Do the BITE test of the ISIS indicator (Ref. AMM TASK 34-22-25-740-001).
E. Test of the ISIS Indicator with the Boresighting Function (with Standard V2)
(1) Hold the ISIS indicator (1) in the correct position and tighten the adjusting screws (3).
5. Close-up(1) Hold the ISIS indicator (1) in the correct position and tighten the adjusting screws (3).
| ACTION | RESULT |
|---|---|
| On the front face of the ISIS indicator: | On the front face of the ISIS indicator: |
| - Push and hold the BUGS and LS pushbutton switches for more than two seconds. | - The maintenance mode comes on and the MAINTENANCE page comes into view. - A blue indication comes into view in the bottom part of the screen. |
| - Push the + (plus) or - (minus) pushbutton switch. | - Different blue indications come into view one after the other. |
| - When the blue BORESIGHTING indication comes into view, push the BARO knob/pushbutton switch. | - The BORESIGHTING READING page comes into view. On the BORESIGHTING READING page: - The difference between the ISIS attitude angles and the ADIRU attitude angles is less than 1.5 degrees for the pitch and the roll. If it is more than 1.5 degrees, move the ISIS indicator to its housing. NOTE: On the BORESIGHTING READING page: - If the KO indications for the ADIRU pitch and roll values are shown and the LEVELING NOT POSSIBLE message is shown, make sure that the ADIRUs are aligned. - If the KO indications for the ISIS pitch and roll values are shown and the LEVELING NOT POSSIBLE message is shown, stop the movement of the aircraft. Do the test again. |
| - Push the - (minus) pushbutton switch adjacent to the START LEVELING indication. | - The LEVELING IN PROGRESS page comes into view. - After 90 seconds, the LEVELING page comes into view and shows RESULT: OK. |
| - Push the RST pushbutton switch to go back to the initial configuration. | |
Subtask 34-22-25-410-050-A ** ON A/C NOT FOR ALL
A. Put the aircraft back to its initial configuration.
(1) Install the thermoformed cover on the center instrument panel.
(2) Install the sidewall panel 211LW (Ref. AMM TASK 25-13-41-400-002).
(3) Make sure that the work area is clean and clear of tools and other items.
(1) Install the thermoformed cover on the center instrument panel.
(2) Install the sidewall panel 211LW (Ref. AMM TASK 25-13-41-400-002).
(3) Make sure that the work area is clean and clear of tools and other items.