Installation of the Lower Bifurcation Latches [IAE]

TASK 78-32-53-400-010-A
Installation of the Lower Bifurcation Latches

FIN: 1000EM1 ** ON A/C NOT FOR ALL
FIN: 1000EM2 ** ON A/C NOT FOR ALL

1. Reason for the Job
Self explanatory
2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment

REFERENCE	QTY	DESIGNATION
No specific	AR	ACCESS PLATFORM 2M (6 FT)
No specific	AR	DYNAMOMETER 44.5 DAN ( 100 LBF) - PUSH PULL
No specific	AR	WARNING NOTICE(S)
No specific	Torque wrench: range to between 425 and 375 lbf.in (4.80 and 4.24 m.daN )
No specific	Torque wrench: range to between 475 and 425 lbf.in (5.37 and 4.80 m.daN )

B. Work Zones and Access Panels

ZONE/ACCESS	ZONE DESCRIPTION
FOR [1000EM1] (ENGINE-1)
437AL, 438AR, 451AL, 452AR
FOR [1000EM2] (ENGINE-2)
447AL, 448AR, 461AL, 462AR

C. Referenced Information

REFERENCE	DESIGNATION
TASK 70-23-11-911-013-A	General Torque Tightening Techniques
TASK 71-13-00-010-010-A	Opening of the Fan Cowls 437AL(447AL),438AR(448AR)
TASK 71-13-00-410-010-A	Closing 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 78-30-00-440-012-A	Re-activation of the Thrust Reverser Hydraulic Control Unit (HCU) after Ground Maintenance
TASK 78-31-00-710-041-A	Operational Test of the Thrust Reverser System with the CFDS
TASK 78-31-00-710-041-A-02	Operational test of the Thrust Reverser without the CFDS and Engine Running
TASK 78-32-00-010-010-A	Opening of the Thrust Reverser Halves
TASK 78-32-00-410-010-A	Closing of the Thrust Reverser Halves
Bifurcation Latch Hook
Bifurcation Latch Keeper
Front Latch Hook
Front Latch Keeper
Lower Bifurcation Latch Bumpers

3. Job Set-up
Subtask 78-32-53-860-050-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).
(3) Make sure that the ACCESS PLATFORM 2M (6 FT) is in position.

Subtask 78-32-53-010-052-A ** ON A/C NOT FOR ALL

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 78-32-53-040-051-A ** ON A/C NOT FOR ALL

C. Make sure that the thrust reverser Hydraulic Control Unit (HCU) is deactivated (Ref. AMM TASK 78-30-00-040-012).

4. Procedure
Subtask 78-32-53-420-050-A ** ON A/C NOT FOR ALL

A. Install the latch hook assembly.

Bifurcation Latch Hook ** ON A/C NOT FOR ALL

(1) Install the latch hook (6) in the latch housing (5) with the bolt (4), the washer (2), the two bushings (3), and the nut (1).
(2) TORQUE the nut to between 475 and 425 lbf.in (5.37 and 4.80 m.daN )

(Ref. AMM TASK 70-23-11-911-013).

NOTE: This subtask is the same for each of the three bifurcation latches.

Subtask 78-32-53-420-051-A ** ON A/C NOT FOR ALL

B. Install the latch keeper assembly.

Bifurcation Latch Keeper ** ON A/C NOT FOR ALL

(1) Put the latch keeper adjustment nut assembly (16) in the latch keeper housing (18) and hold it in position.
(2) Put the threaded end of the latch keeper (17) through the keeper housing and engage it in the threads of the adjustment nut (16).
(3) Use a 5/32 in. hexagonal wrench and turn the latch keeper adjustment nut in a counterclockwise direction. This will pull the keeper shaft in to the adjustment nut assembly.

NOTE: This subtask is the same for each of three bifurcation latches.

Subtask 78-32-53-420-052-A ** ON A/C NOT FOR ALL

C. Install the front latch hook assembly.

Front Latch Hook ** ON A/C NOT FOR ALL

(1) Install the spring (31) in the front latch hook (36).
(2) Put the front latch hook in the latch hook housing (32) and hold it in position. Make sure that the latch indicator arm (33) is above the latch handle (34). This makes sure that the indicator arm will move when the latch handle is closed.
(3) Install the bolt (35), the two bushings (30), the washer (29) and the nut (28) that attach the latch hook to the latch hook housing.
(4) TORQUE the nut to between 425 and 375 lbf.in (4.80 and 4.24 m.daN )

(Ref. AMM TASK 70-23-11-911-013).
(5) Attach the spring (31) to the spring support plate (37).

Subtask 78-32-53-420-053-A ** ON A/C NOT FOR ALL

D. Install the front latch keeper assembly.

Front Latch Keeper ** ON A/C NOT FOR ALL

(1) Install the adjustment nut assembly (16) on the keeper mount pad (47) with the two screws (50).
(2) Engage the threaded end of the keeper (48) in the threads of the adjustment nut assembly.
(3) Install the set screw (49) in the threaded end of the keeper.

Subtask 78-32-53-820-050-A ** ON A/C NOT FOR ALL

E. Do a check of the closing force at each of the four lower bifurcation latches (1).

Lower Bifurcation Latch Bumpers ** ON A/C NOT FOR ALL

(1) Attach the DYNAMOMETER 44.5 DAN ( 100 LBF) - PUSH PULL to the tip of the latch.
(2) Make sure the force necessary to close the latch is between 45 lbf (20 daN) and 55 lbf (24.5 daN)
(3) Adjust the latches if necessary:
(a) Use a 5/32 in. hexagonal wrench to turn the latch keeper adjustment nut (16) in a clockwise direction. This increases the latch closing force.
(b) Use the hexagonal wrench to turn the latch keeper adjustment nut in a counterclockwise direction. This decreases the latch closing force.

5. Close-up
Subtask 78-32-53-410-050-A ** ON A/C NOT FOR ALL

A. Close Access
(1) Make sure that the work area is clean and clear of tools and other items.
(2) Close the thrust reverser halves (Ref. AMM TASK 78-32-00-410-010):
(a) FOR [1000EM1] (ENGINE-1)
451AL 452AR.
(b) FOR [1000EM2] (ENGINE-2)
461AL 462AR.

Subtask 78-32-53-440-050-A ** ON A/C NOT FOR ALL

B. Activate the thrust reverser HCU (Ref. AMM TASK 78-30-00-440-012).

Subtask 78-32-53-410-051-A ** ON A/C NOT FOR ALL

C. Close Access
(1) Close the fan cowls (Ref. AMM TASK 71-13-00-410-010):
(a) FOR [1000EM1] (ENGINE-1)
437AL 438AR.
(b) FOR [1000EM2] (ENGINE-2)
447AL 448AR.
(2) Remove the WARNING NOTICE(S).
(3) Remove the access platform(s).

Subtask 78-32-53-710-050-A ** ON A/C NOT FOR ALL

D. Operational Test
(1) Do an operational test of the thrust reverser system (Ref. AMM TASK 78-31-00-710-041).

NOTE: As an alternative procedure, you can do the operational test without the CFDS (Ref. AMM TASK 78-31-00-710-041).

[Rev.10 from 2021] 2026.04.01 03:29:08 UTC