DOC AIRBUS | AMM A320FInstallation of the Latch Mechanism
TASK 52-51-21-400-001-A
Installation of the Latch Mechanism
1. Reason for the Job
Self explanatory
2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment
B. Consumable Materials
C. Referenced Information
3. Job Set-up
Subtask 52-51-21-860-050-A
Subtask 52-51-21-420-050-F
Subtask 52-51-21-410-050-A
[Rev.10 from 2021]
2026.04.02 06:28:26 UTC
Installation of the Latch Mechanism
1. Reason for the Job
Self explanatory
2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment
| REFERENCE | QTY | DESIGNATION |
|---|---|---|
| No specific | Torque wrench: range to between 0.374 and 0.306 m.daN (33.10 and 27.08 lbf.in )  |
| REFERENCE | DESIGNATION |
|---|---|
| (Material No.14QFB1) | Wire-Locking Dia: 0.8 mm CRES Nickel Alloy - |
| REFERENCE | DESIGNATION |
|---|---|
Three Latch MechanismSubtask 52-51-21-860-050-A
A. Make sure that the access to the cockpit is available.
Subtask 52-51-21-865-051-A B. Make sure that this(these) circuit breaker(s) is(are) open, safetied and tagged:
4. Procedure| PANEL | DESIGNATION | FIN | LOCATION |
|---|---|---|---|
| ** ON A/C NOT FOR ALL | |||
| 122VU | DOORS/PAX/MONG | 1MQ | T13 |
| ** ON A/C NOT FOR ALL | |||
| 122VU | DOORS CKPT LOCK | 1MQ | T13 |
| 122VU | COCKPIT DOOR LOCK SYSTEM | 1MQ | T13 |
Subtask 52-51-21-420-050-F
A. Installation of the Latch Mechanism
(1) Clean the component interfaces and the adjacent area.
(2) Do an inspection of the component interfaces and the adjacent area.
(3) Install the center latch (30) as follows:
(a) Put the center latch (30) in its installation position and attach it with the screws (32).
(b) Make sure that the edge of the center latch (30) aligns with the edge of the cockpit door (13).
(c) Install the caps (31) on the screws (32) of the center latch (30).
(4) Install the top or lower connection rod (23) as follows:
(a) Make sure that the jam nuts (26) are installed on the eye-ends (27) and (29).
(b) Install the safety devices (24) and (25) on the eye-ends (27) and (29).
(c) Install the top or lower connection rod (23) on the eye-ends (27) and (29).
(5) Install the top or lower latch mechanism (28) as follows:
(a) Put the top or lower latch mechanism (28) in position on the door (13) and attach it with the screws (22) and the washers (21). (a) If you cannot install the screws (22) easily, turn the applicable connection rod (23) as necessary.
(b) Make sure that the edge of the top or lower latch mechanism (28) aligns with the edge of the cockpit door (13).
Subtask 52-51-21-820-050-B (1) Clean the component interfaces and the adjacent area.
(2) Do an inspection of the component interfaces and the adjacent area.
(3) Install the center latch (30) as follows:
(a) Put the center latch (30) in its installation position and attach it with the screws (32).
(b) Make sure that the edge of the center latch (30) aligns with the edge of the cockpit door (13).
(c) Install the caps (31) on the screws (32) of the center latch (30).
(4) Install the top or lower connection rod (23) as follows:
(a) Make sure that the jam nuts (26) are installed on the eye-ends (27) and (29).
(b) Install the safety devices (24) and (25) on the eye-ends (27) and (29).
(c) Install the top or lower connection rod (23) on the eye-ends (27) and (29).
(5) Install the top or lower latch mechanism (28) as follows:
(a) Put the top or lower latch mechanism (28) in position on the door (13) and attach it with the screws (22) and the washers (21). (a) If you cannot install the screws (22) easily, turn the applicable connection rod (23) as necessary.
(b) Make sure that the edge of the top or lower latch mechanism (28) aligns with the edge of the cockpit door (13).
B. Adjustment of the Latch Mechanism
(b) Loosen the two jam nuts (26) of each connection rod (23).
(c) Turn each connection rod (23) until:
.
(e) Safety the jam nuts (26) with14QFB1 Wire-Locking Dia: 0.8 mm CRES Nickel Alloy -
(2) Adjust the position of the center latch mechanism (30) as follows:
(a) If necessary, remove the caps (31).
(b) If necessary, loosen the screws (32).
(c) Move the latch mechanism (30) until its tenon engages in the catch of the lavatory wall to between 7.0 mm (0.2756 in.) and 9.0 mm (0.3543 in.) in depth.
(d) Make sure that dimension A is correct.
(e) If loosened, tighten the screws (32).
(f) If removed, install the caps (31).
(3) Adjust the position of the top and lower latch mechanism (28) as follows:
(a) Loosen the screws (22).
(b) Move the latch mechanism (28) until its tenon engages in the catch of the lavatory wall to between 7.0 mm (0.2756 in.) and 9.0 mm (0.3543 in.) in depth.
(c) Make sure that dimension A is correct.
(d) If loosened, tighten the screws (22).
(e) Make sure that the top and bottom latch tenons are in the closed position before the center latch tenon engages.
Subtask 52-51-21-420-051-A CAUTION:
USE THE DOUBLE WRENCHING PROCEDURE TO TORQUE THE JAM NUTS. USE ONE WRENCH ON THE JAM NUT AND A SECOND WRENCH ON THE ROD. ALSO MAKE SURE THAT YOU DO NOT APPLY TOO MUCH TORQUE TO THE JAM NUTS. IF YOU DO NOT USE THIS PROCEDURE, THE APPLIED TORQUE CAN TWIST THE BELL CRANK. IF YOU APPLY TOO MUCH TORQUE, THE BELL CRANK WILL BREAK.
(1) Adjust the length of the top or lower connection rod (23) as follows: WARNING:
USE PROTECTIVE GOGGLES AND GLOVES WHEN YOU REMOVE OR INSTALL LOCKWIRE. EACH TIME YOU CUT LOCKWIRE, REMOVE AND DISCARD IT IMMEDIATELY. LOOSE LOCKWIRE CAN CUT YOU OR MAKE YOU BLIND, AND/OR CAN CAUSE DAMAGE.
(a) If necessary, remove the lockwire from the safety devices (24) and the jam nuts (26). (b) Loosen the two jam nuts (26) of each connection rod (23).
(c) Turn each connection rod (23) until:
- The latch tenons of the top and lower latch mechanism are fully extended
- There is no play in the linkage.
NOTE: Each connection rod (23) has a right thread at one end and a left thread at the other end. Thus, you can adjust the length of each connection rod (23) if you turn its barrel.
(d) Torque the jam nuts (26) against the barrel of the connection rod (23) maximum to between 0.374 and 0.306 m.daN (33.10 and 27.08 lbf.in ) . (e) Safety the jam nuts (26) with
(2) Adjust the position of the center latch mechanism (30) as follows:
(a) If necessary, remove the caps (31).
(b) If necessary, loosen the screws (32).
(c) Move the latch mechanism (30) until its tenon engages in the catch of the lavatory wall to between 7.0 mm (0.2756 in.) and 9.0 mm (0.3543 in.) in depth.
(d) Make sure that dimension A is correct.
(e) If loosened, tighten the screws (32).
(f) If removed, install the caps (31).
(3) Adjust the position of the top and lower latch mechanism (28) as follows:
(a) Loosen the screws (22).
(b) Move the latch mechanism (28) until its tenon engages in the catch of the lavatory wall to between 7.0 mm (0.2756 in.) and 9.0 mm (0.3543 in.) in depth.
(c) Make sure that dimension A is correct.
(d) If loosened, tighten the screws (22).
(e) Make sure that the top and bottom latch tenons are in the closed position before the center latch tenon engages.
C. Installation of the Rod Covers
(1) Install the two rod covers (4) and (12) as follows:
(a) Put the rod covers (4) and (12) in their installation position on the cockpit door (3).
(b) Make sure that the mouting holes of the rod covers (4) and (12) align with the attachment holes of the mounting block (11).
(c) Attach the rod covers (4) and (12) with the screws (2), (6) and (9) with the washers (2), (7) and (8).
(d) Install the caps (1), (5) and (10) on the screws (2), (6) and (9).
(2) Install the two rod covers (4) and (12) with the new mounting block (11) as follows:
(a) Put the mounting blocks (11) on the rod covers (4) and (12) and attach them with the screws (9) and the washers (8).
(b) Put the rod covers (4) and (12) in their installation position of the cockpit door (3).
(c) Make sure that the bonding surface of the mounting blocks (11) are correctly attached on the cockpit door (3).
(d) Attach the rod covers (4) and (12) with the screws (2) and (6) and the washers (3) and (7).
(e) Install the caps (1), (5) and (10) on the screws (2), (6) and (9).
Subtask 52-51-21-710-050-C (1) Install the two rod covers (4) and (12) as follows:
(a) Put the rod covers (4) and (12) in their installation position on the cockpit door (3).
(b) Make sure that the mouting holes of the rod covers (4) and (12) align with the attachment holes of the mounting block (11).
(c) Attach the rod covers (4) and (12) with the screws (2), (6) and (9) with the washers (2), (7) and (8).
(d) Install the caps (1), (5) and (10) on the screws (2), (6) and (9).
(2) Install the two rod covers (4) and (12) with the new mounting block (11) as follows:
(a) Put the mounting blocks (11) on the rod covers (4) and (12) and attach them with the screws (9) and the washers (8).
(b) Put the rod covers (4) and (12) in their installation position of the cockpit door (3).
(c) Make sure that the bonding surface of the mounting blocks (11) are correctly attached on the cockpit door (3).
(d) Attach the rod covers (4) and (12) with the screws (2) and (6) and the washers (3) and (7).
(e) Install the caps (1), (5) and (10) on the screws (2), (6) and (9).
D. Operational Test
(1) Make sure that the cockpit door is open.
(2) Do this test to make sure that the latch mechanism operates correctly.
Subtask 52-51-21-865-052-A (1) Make sure that the cockpit door is open.
(2) Do this test to make sure that the latch mechanism operates correctly.
| ACTION | RESULT |
|---|---|
| 1.On the Cockpit Door from the Cockpit Side: | On the Cockpit Door |
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2.On the Cockpit Door from the Cabin Side:
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E. Remove the safety clip(s) and the tag(s) and close this(these) circuit breaker(s):
5. Close-up| PANEL | DESIGNATION | FIN | LOCATION |
|---|---|---|---|
| ** ON A/C NOT FOR ALL | |||
| 122VU | DOORS/PAX/MONG | 1MQ | T13 |
| ** ON A/C NOT FOR ALL | |||
| 122VU | DOORS CKPT LOCK | 1MQ | T13 |
| 122VU | COCKPIT DOOR LOCK SYSTEM | 1MQ | T13 |
Subtask 52-51-21-410-050-A
A. Put the aircraft back to the serviceable condition.