Removal of the Vent Door Mechanism

TASK 52-31-21-000-003-A
Removal of the Vent Door Mechanism

CAUTION: IMMEDIATELY AFTER YOU OPEN THE CARGO COMPARTMENT DOOR, RECORD ON THE WORK CARD ON THE DOOR, THE DATE AND TIME WHEN YOU OPENED IT. IF THE CARGO COMPARTMENT DOOR STAYS OPEN FOR 12 HOURS OR MORE, YOU MUST BLEED THE HYDRAULIC SYSTEM RELATED TO IT. IF YOU DO NOT OBEY THESE PRECAUTIONS, THE DOOR CAN CLOSE SUDDENLY WHEN YOU SET THE DOOR TO "CLOSE". THIS CAN CAUSE DAMAGE TO THE DOOR AND TO THE AIRCRAFT STRUCTURE.

1. Reason for the Job
To replace the gear box, the different levers and the related connection rods of the vent door mechanism.
2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment

REFERENCE	QTY	DESIGNATION
No specific	1	ACCESS PLATFORM 4M (13 FT)-ADJUSTABLE
No specific	AR	SAFETY CLIP - CIRCUIT BREAKER

B. Work Zones and Access Panels

ZONE/ACCESS	ZONE DESCRIPTION
825AR

C. Referenced Information

REFERENCE	DESIGNATION
TASK 52-30-00-860-001-A	Open the FWD or Aft Cargo-Compartment Door with the Yellow Electric Pump
TASK 52-31-13-000-001-A	Removal of the Lining and the Insulation
Linkage of the Vent Door Mechanism ** ON A/C NOT FOR ALL
Linkage of the Vent Door Mechanism ** ON A/C NOT FOR ALL
Gear Box of the Vent Door Mechanism ** ON A/C NOT FOR ALL
Cover of the Vent Door Mechanism ** ON A/C NOT FOR ALL

3. Job Set-up
Subtask 52-31-21-010-054-A

A. Get Access
(1) Open the FWD cargo-compartment door (referred to as cargo door) and safety it with the actuator safety locks (Ref. AMM TASK 52-30-00-860-001).
(2) Put the ACCESS PLATFORM 4M (13 FT)-ADJUSTABLE in position below the opened cargo door.

Subtask 52-31-21-865-056-A

B. Open, safety and tag this(these) circuit breaker(s):

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C NOT FOR ALL
121VU	HYDRAULIC/HYD POWER/Y	3803GX	N30
** ON A/C NOT FOR ALL
121VU	HYDRAULIC/HYD POWER/Y	3803GX	N31
** ON A/C ALL
122VU	DOORS/CARGO	1MJ	T12
123VU	Y HYD/ELEC/PUMP	3802GX	AB06
123VU	Y HYD/ELEC/ELEC PUMP/NORM	3801GX	AB03

Subtask 52-31-21-010-053-A

C. Get Access
(1) Remove the access panel 825AR from the cargo door.
(2) Remove the lining and the insulation of the cargo door to get access to the upper end of the gear box (Ref. AMM TASK 52-31-13-000-001).
(3) Remove the vent door cover from the internal door structure to get access to the actuator arm of the vent door.

4. Procedure
Subtask 52-31-21-020-051-B ** ON A/C NOT FOR ALL

A. Removal of the Gear Box Linkage

Linkage of the Vent Door Mechanism ** ON A/C NOT FOR ALL

(1) Disconnect the drawbar (71) from the shaft lever (76) as follows:
(a) Remove and discard the cotter pin (75) from the nut (74).
(b) Remove the nut (74), the washers (73) and the bolt (72) from the shaft lever (76).
(c) Remove the eye end of the drawbar (71) from the fork end of the shaft lever (76).
(2) Disconnect the drawbar (71) from the actuator arm (107) of the vent door as follows:
(a) Remove and discard the cotter pin (103) from the nut (104).
(b) Remove the nut (104), the washers (105), the bush (106) and the bolt (108) from the actuator arm (107).
(c) Remove the eye end of the drawbar (71) from the actuator arm (107).
(3) Disconnect the connection rod (82) from the vent door lever (85) of the safety shaft as follows:
(a) Remove and discard the cotter pin (87) from the nut (86).
(b) Remove the nut (86), the washers (84) and the bolt (83) from the vent door lever (85).
(c) Remove the lower eye end of the connection rod (82) from the fork end of the vent door lever (85).
(4) Disconnect the connection rod (82) from the lever (80) as follows:
(a) Remove and discard the cotter pin (77) from the nut (78).
(b) Remove the nut (78), the washers (79) and the bolt (81) from the lever (80).
(c) Remove the upper eye end of the connection rod (82) from the fork end of the lever (80).
(5) Disconnect the link assy (88) from the target lever (90) as follows:
(a) Remove and discard the cotter pin (91) from the nut (92).
(b) Remove the nut (92), the washer (93), the sleeve (94) and the bolt (89) from the link assy (88).
(c) Remove the fork end of the link assy (88) from the target lever (90).
(6) Disconnect the link assy (88) from the drive shaft lever (102) as follows:
(a) Remove and discard the cotter pin (96) from the nut (97).
(b) Remove the nut (97) and the washer (98) from the drive shaft lever (102).
(c) Remove the eye end of the link assy (88) from the drive shaft lever (102).

Subtask 52-31-21-020-068-A ** ON A/C NOT FOR ALL

B. Removal of the Gearbox

Gear Box of the Vent Door Mechanism ** ON A/C NOT FOR ALL

(1) Disassemble the drive shaft lever (102) from the drive shaft of the gear box (123) as follows:
(a) Remove the nuts (128), the washers (127), the sleeves (126) and the tapered pins (125) from the lever (124).
(b) Remove the nuts (133), the washers (132), the sleeves (126) and the tapered pins (129) from the safety cam (130).
(c) Hold the safety cam (130) so that it does not fall down during the removal of the drive shaft lever (102).
(d) Pull the drive shaft lever (102) from the cargo door frame and remove the safety cam (130).
(2) Remove the shaft lever (76) from the output shaft of the gear box (123) as follows:
(a) Remove the nuts (120), the sleeves (121) and the tapered pins (111) from the shaft lever (76).
(b) Remove the protection plug (110) from the shaft lever (76).
(c) Move the shaft lever (76) from the output of the gear box (123).
(3) Remove the gear box (123) together with the lever (124) from the cargo door structure as follows:
(a) Support the gear box (123) and remove the screws (119) and the washers (118) from the longeron (116).
(b) Move the output shaft down through the flange bearing (122) and the structural bearings at longeron (116).
(c) Remove the gear box (123) together with the laminated shim (115) and the lever (124) from the longeron (116).
(d) Remove the laminated shim (115) from the output shaft of the gear box (123).
(e) Remove the lever (124) from the drive shaft of the gear box (123).
(4) If necessary, remove the nuts (114), the washers (113), the bolts (112) and the flange bearing (122) from the support bracket (117).

Subtask 52-31-21-020-051-C ** ON A/C NOT FOR ALL

C. Removal of the Vent Door Linkage

Linkage of the Vent Door Mechanism ** ON A/C NOT FOR ALL

(1) Remove the connection rod (16) as follows:
(a) Remove and discard the cotter pin (5) from the nut (4).
(b) Remove the nut (4) the washers (3) and the bolt (2).
(c) Remove the connection rod (16) from the lever of the vent door (1).
(d) Remove and discard the cotter pin (10).
(e) Remove the nut (9), the washers (7), and the bolt (6).
(f) Remove the connection rod (16) from the drive lever (8).
(2) Remove the connection rod (23) as follows:
(a) Remove and discard the cotter pin (12) from the nut (13).
(b) Remove the nut (13), the washers (14) and the bolt (15).
(c) Disconnect the connection rod (23) from the lever (11).
(d) Remove and discard the cotter pin (22) from the nut (21).
(e) Remove the nut (21), the washers (17) and the bolt (18) from the lever twin (19).
(f) Remove the connection rod (23) from the twin lever (19).

Subtask 52-31-21-020-068-C ** ON A/C NOT FOR ALL

D. Removal of the Cover Assembly of the Vent Door Mechanism

Cover of the Vent Door Mechanism ** ON A/C NOT FOR ALL

(1) Make sure the fork-end of the drive rod (1) is clear of the shaft lever (3).
(2) Remove the nut (5), the spacer (4) and the tapered pin (2).
(3) Remove the shaft lever (3) from the shaft (16).
(4) Remove and discard the cotter pin (10).
(5) Remove the nut (9), the washer (8), the bolt (14) and the washer (13).
(6) Disconnnect the fork-end of the connectionlink (12) from the shaft lever (15).
(7) Remove the nut (6), the spacer (7) and the tapered pin (11).
(8) Remove the bolts (19), the washers (18) and the cover assembly (17) from the beam 4.

[Rev.10 from 2021] 2026.04.02 06:27:52 UTC