DOC AIRBUS | AMM A320FCheck the Installation of the VSV Unison Ring Connectors - SBE 72-0400 [IAE]
TASK 75-32-42-400-013-B
Check the Installation of the VSV Unison Ring Connectors - SBE 72-0400
1. Reason for the Job
SBE 72-0400: HP compressor variable vanes - inlet guide vane and stages 3 to 5 with optimized build and setting instructions.
This procedure is to be used to make sure that the VSV unison ring connectors are installed correctly.
2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment
B. Work Zones and Access Panels
C. Referenced Information
3. Job Set-up
Subtask 75-32-42-860-057-A ** ON A/C NOT FOR ALL
Subtask 75-32-42-200-054-A ** ON A/C NOT FOR ALL
[Rev.10 from 2021]
2026.04.01 03:12:15 UTC
Check the Installation of the VSV Unison Ring Connectors - SBE 72-0400
1. Reason for the Job
SBE 72-0400: HP compressor variable vanes - inlet guide vane and stages 3 to 5 with optimized build and setting instructions.
This procedure is to be used to make sure that the VSV unison ring connectors are installed correctly.
2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment
| REFERENCE | QTY | DESIGNATION |
|---|---|---|
| No specific | AR | WARNING NOTICE(S) |
| ZONE/ACCESS | ZONE DESCRIPTION |
|---|---|
| FOR [1000EM1] (ENGINE-1) | |
| 437AL, 438AR, 451AL, 452AR | |
| FOR [1000EM2] (ENGINE-2) | |
| 447AL, 448AR, 461AL, 462AR | |
| REFERENCE | DESIGNATION |
|---|---|
| TASK 71-13-00-010-010-A | Opening of the Fan Cowls 437AL(447AL),438AR(448AR) |
| TASK 78-30-00-040-012-A | Deactivation of the Thrust Reverser Hydraulic Control Unit (HCU) for Ground Maintenance |
| TASK 78-32-00-010-010-A | Opening of the Thrust Reverser Halves |
Subtask 75-32-42-860-057-A ** ON A/C NOT FOR ALL
A. Aircraft Maintenance Configuration
(1) On the center pedestal, on the ENG panel 115VU, make sure that a WARNING NOTICE(S) is in position to tell persons not to start the engine.
(2) On the overhead maintenance panel 50VU, make sure that the ON legend of the ENG/FADEC GND PWR/1(2) pushbutton switch is off. Make sure that a WARNING NOTICE(S) is in position to tell persons not to energize the FADEC 1(2).
Subtask 75-32-42-010-090-A ** ON A/C NOT FOR ALL (1) On the center pedestal, on the ENG panel 115VU, make sure that a WARNING NOTICE(S) is in position to tell persons not to start the engine.
(2) On the overhead maintenance panel 50VU, make sure that the ON legend of the ENG/FADEC GND PWR/1(2) pushbutton switch is off. Make sure that a WARNING NOTICE(S) is in position to tell persons not to energize the FADEC 1(2).
B. Get Access
(1) Make sure that the fan cowl doors are open: (Ref. AMM TASK 71-13-00-010-010)
(a) FOR [1000EM1] (ENGINE-1)
437AL 438AR
(b) FOR [1000EM2] (ENGINE-2)
447AL 448AR
(2) Make sure that the thrust reverser doors are open: (Ref. AMM TASK 78-32-00-010-010)
(a) FOR [1000EM1] (ENGINE-1)
451AL 452AR
(b) FOR [1000EM2] (ENGINE-2)
461AL 462AR
Subtask 75-32-42-040-073-A ** ON A/C NOT FOR ALL (1) Make sure that the fan cowl doors are open: (Ref. AMM TASK 71-13-00-010-010)
(a) FOR [1000EM1] (ENGINE-1)
437AL 438AR
(b) FOR [1000EM2] (ENGINE-2)
447AL 448AR
(2) Make sure that the thrust reverser doors are open: (Ref. AMM TASK 78-32-00-010-010)
(a) FOR [1000EM1] (ENGINE-1)
451AL 452AR
(b) FOR [1000EM2] (ENGINE-2)
461AL 462AR
C. Make sure that the thrust reverser Hydraulic Control Unit (HCU) is deactivated: (Ref. AMM TASK 78-30-00-040-012)
4. ProcedureSubtask 75-32-42-200-054-A ** ON A/C NOT FOR ALL
A. Check the Installation of the Left and Right Hand Connectors and VSV Unison Ring Assembly
(1) This check must be done after each time the connectors are installed to the VSV actuating ring assemblies.
(2) This is the general procedure to make sure that the left and right hand connectors which are installed to the upper and lower actuating rings are installed correctly. The check will make sure that the dowels which hold the connectors to the actuating ring are installed correctly and are not mis-seated.
(a) The following gives the causes of an incorrectly installed assembly and what to look for:
It is not easy to decide if the connectors for a particular stage are installed incorrectly. An incorrect installation can occur if a dowel is not installed correctly in a mating hole of an actuating ring and instead touches the mating face of the actuating ring.
The wall of the actuating ring can become clamped between the dowel and the internal actuating ring boss, when this occurs the bridge piece is not held. The head of the mis-seated dowel can be visible above the connector and/or the connector could be offset from the actuating ring.
SBE 72-0400: Check tne connector/bridge piece assemblies to VSV actuating ring installation for mis-seated down. ** ON A/C NOT FOR ALL
No indication of misaligned connectors is evident when the bolt(s) are torque tightened because of a "cross-keying" action of the dowels in the connectors.
(3) Inspect the left hand and right hand actuating ring and connetor joint for each stage.
(a) Check the clearance between the connector and the unison ring.
Check the clearance between the connector and the actuating ring, it should be possible to put a 0.001 in. or 0.002 in. (0,025 mm or 0,05 mm) feeler gauge in the clearance. If this is not possible do the next step.
For the left hand and/or right hand joint (as applicable) examine the dowel heads, use a torch if necessary. Make a comparison in the position of each dowel. Look for differences in radial distances between the connector and the upper and lower actuating ring, all the distances should be the same. If there is a distance which does not appear regular then do the next two steps.
Remove the connector and look for new marks on the actuating ring adjacent to the dowel mating hole caused by a mis-aligned dowel.
(b) Install the connector and make sure the dowels are correctly seated before you torque tighten the bolts.
(1) This check must be done after each time the connectors are installed to the VSV actuating ring assemblies.
(2) This is the general procedure to make sure that the left and right hand connectors which are installed to the upper and lower actuating rings are installed correctly. The check will make sure that the dowels which hold the connectors to the actuating ring are installed correctly and are not mis-seated.
(a) The following gives the causes of an incorrectly installed assembly and what to look for:
It is not easy to decide if the connectors for a particular stage are installed incorrectly. An incorrect installation can occur if a dowel is not installed correctly in a mating hole of an actuating ring and instead touches the mating face of the actuating ring.
The wall of the actuating ring can become clamped between the dowel and the internal actuating ring boss, when this occurs the bridge piece is not held. The head of the mis-seated dowel can be visible above the connector and/or the connector could be offset from the actuating ring.
SBE 72-0400: Check tne connector/bridge piece assemblies to VSV actuating ring installation for mis-seated down. ** ON A/C NOT FOR ALL No indication of misaligned connectors is evident when the bolt(s) are torque tightened because of a "cross-keying" action of the dowels in the connectors.
(3) Inspect the left hand and right hand actuating ring and connetor joint for each stage.
(a) Check the clearance between the connector and the unison ring.
Check the clearance between the connector and the actuating ring, it should be possible to put a 0.001 in. or 0.002 in. (0,025 mm or 0,05 mm) feeler gauge in the clearance. If this is not possible do the next step.
For the left hand and/or right hand joint (as applicable) examine the dowel heads, use a torch if necessary. Make a comparison in the position of each dowel. Look for differences in radial distances between the connector and the upper and lower actuating ring, all the distances should be the same. If there is a distance which does not appear regular then do the next two steps.
Remove the connector and look for new marks on the actuating ring adjacent to the dowel mating hole caused by a mis-aligned dowel.
(b) Install the connector and make sure the dowels are correctly seated before you torque tighten the bolts.