Removal of the Variable Bleed Valves (VBVs) Turnbuckles and Bellcranks [CFML]

TASK 72-24-81-000-801-A
Removal of the Variable Bleed Valves (VBVs) Turnbuckles and Bellcranks

WARNING: BE CAREFUL WHEN YOU DO WORK ON THE ENGINE PARTS AFTER THE ENGINE SHUTDOWN. USE APPLICABLE THERMAL GLOVES. THE ENGINE PARTS CAN STAY HOT FOR ONE HOUR AFTER SHUTDOWN AND CAN BURN YOU.

ZONE: 400

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

REFERENCE	QTY	DESIGNATION
No specific	1	ACCESS PLATFORM 1M(3 FT)
No specific	AR	WARNING NOTICE(S)

B. Work Zones and Access Panels

ZONE/ACCESS	ZONE DESCRIPTION
400	POWER PLANT, NACELLES AND PYLONS
FOR [4020KM1] (POWER PLANT-DEMOUNTABLE, ENGINE 1)
437AL, 438AR, 451AL, 452AR
FOR [4020KM2] (POWER PLANT-DEMOUNTABLE, ENGINE 2)
447AL, 448AR, 461AL, 462AR

C. Referenced Information

REFERENCE	DESIGNATION
TASK 71-13-00-010-803-A	Opening of the Fan Cowl Doors
TASK 72-21-01-000-802-A	Removal of the FlowPath Panel
TASK 72-24-01-000-801-A	Removal of Segment Shrouds 1 thru 5
TASK 72-24-20-000-801-A	Removal of the Outlet Guide Vane (OGV)
TASK 72-24-20-400-801-A	Installation of the Outlet Guide Vane (OGV)
TASK 75-31-05-000-801-A	Removal of the Left Variable Bleed Valve (VBV) Actuator
TASK 75-31-05-000-802-A	Removal of the Right Variable Bleed Valve (VBV) Actuator
TASK 78-30-00-040-809-A	Deactivation of the Thrust Reverser System for Ground Maintenance
TASK 78-36-00-010-806-A	Opening of the Thrust Reverser Cowl Doors
TASK 79-21-30-000-802-A	Removal of the Engine Surface Air Cooling Oil Cooler (SACOC)
Turnbuckles and Bellcrank
VBV Turnbuckles and Bellcrank Access

3. Job Set-up
Subtask 72-24-81-941-050-A

A. Safety Precautions
(1) On the center pedestal, on ENG panel 115VU:
(a) Make sure that the ENG/MODE selector switch is in the NORM position.
(b) Make sure that the ENG/MASTER 1(2) control switch was in the OFF position not less than five minutes before you do this procedure.
(c) Put WARNING NOTICE(S) in position to tell persons not to operate:

The ENG/MODE selector switch and
The ENG/MASTER 1(2) control switch.

(2) On the ENG section of maintenance panel 50VU:
(a) Make sure that the ON legend of the FADEC GND PWR/1(2) pushbutton switch is off.
(b) Put a WARNING NOTICE(S) in position to tell persons not to energize FADEC 1(2).

Subtask 72-24-81-010-050-A

B. Get Access
(1) Open the fan cowl doors (Ref. AMM TASK 71-13-00-010-803):
(a) FOR [4020KM1] (POWER PLANT-DEMOUNTABLE, ENGINE 1)
437AL 438AR.
(b) FOR [4020KM2] (POWER PLANT-DEMOUNTABLE, ENGINE 2)
447AL 448AR.
(2) Put an ACCESS PLATFORM 1M(3 FT) in position.

Subtask 72-24-81-040-050-A

C. Deactivation of the Thrust Reverser System for Maintenance

WARNING: YOU MUST DEACTIVATE THE THRUST REVERSER BEFORE YOU DO WORK ON OR AROUND IT. IF YOU DO NOT, THE THRUST REVERSER CAN OPERATE ACCIDENTALLY AND CAUSE AN INJURY AND/OR DAMAGE.

(1) Do the deactivation of the thrust reverser system for maintenance (Ref. AMM TASK 78-30-00-040-809).

Subtask 72-24-81-010-051-A

D. Open the Thrust Reverser cowl doors (Ref. AMM TASK 78-36-00-010-806):
(1) FOR [4020KM1] (POWER PLANT-DEMOUNTABLE, ENGINE 1)
451AL 452AR.
(2) FOR [4020KM2] (POWER PLANT-DEMOUNTABLE, ENGINE 2)
461AL 462AR.

4. Procedure
Subtask 72-24-81-010-054-A

A. Gain access to the VBV turnbuckles and bellcrank:
(1) Remove the flowpath panel (Ref. AMM TASK 72-21-01-000-802).
(2) Remove the segment shrouds 1 thru 5 (Ref. AMM TASK 72-24-01-000-801).
(3) Remove the VBV actuator (Ref. AMM TASK 75-31-05-000-802) and (Ref. AMM TASK 75-31-05-000-801).
(4) Remove the engine surface air cooling oil cooler (Ref. AMM TASK 79-21-30-000-802).

Subtask 72-24-81-020-050-A

B. Removal of the Master VBV Bellcrank and the Slave and Master Turnbuckles

CAUTION: DO NOT REMOVE MORE THAN TWO OUTLET GUIDE VANES (OGV) AT A TIME. IF YOU DO NOT OBEY THIS INSTRUCTION, DAMAGE TO THE ENGINE CAN OCCUR.

(1)

VBV Turnbuckles and Bellcrank Access

(2) Remove the bolt (15) from the fan hub frame.
(3) Remove the axis (14) from the fan hub frame and from the master bellcrank (13).

NOTE: In case of axis (14) wear it is necessary to align manually the holes of the master bellcrank (13) and the holes of the fan frame to remove the worn axis (14).

(4) Remove the bolt (1) from the VBV actuating ring (3).
(5) Remove and discard the safety wire from the axis (12) and (4).
(6) Remove the axis (12) from the master bellcrank (13) and from the slave turnbuckle (11).
(7) Remove the axis (4) from the master bellcrank (13) and from the master turnbuckle (5).
(8) Remove the master turnbuckle (5).

NOTE: The removed master turnbuckle (5) must be retained in that measurement and is needed for the installation procedure.

NOTE: To increase the clearance between the fan hub frame and the VBV actuating ring (3), it is possible to remove the bolt (1) and the axis (2) on the two adjacent VBV door positions.

(9) Remove the master bellcrank (13).
(10) Remove the nut (10), the washer (9), the bolt (7) and the spacer (8) from the VBV door (6).
(11) Remove the slave turnbuckle (11).

NOTE: The removed slave turnbuckle (11) must be retained in that measurement and is needed for the installation procedure.

(12) Install the two previously removed OGV (Ref. AMM TASK 72-24-20-400-801).

Subtask 72-24-81-020-051-A

C. Removal of the Slave VBV Turnbuckles and Slave Bellcrank

CAUTION: DO NOT REMOVE MORE THAN TWO OUTLET GUIDE VANES (OGV) AT A TIME. IF YOU DO NOT OBEY THIS INSTRUCTION, DAMAGE TO THE ENGINE CAN OCCUR.

(1)

VBV Turnbuckles and Bellcrank Access

(2) Remove the bolt (15) from the fan hub frame.
(3) Remove the axis (14) from the fan hub frame and from the slave bellcrank (16).

NOTE: In case of axis (14) wear it is necessary to align manually the holes of the slave bellcrank (16) and the holes of the fan frame to remove the worn axis (14).

(4) Remove the bolt (1) from the VBV actuating ring (3).
(5) Remove and discard the safety wire from the axis (12).
(6) Remove the axis (12) from the slave bellcrank (16) and from the slave turnbuckle (11).
(7) Remove the slave bellcrank (16).

NOTE: To increase the clearance between the fan hub frame and the VBV actuating ring (3), it is possible to remove the bolt (1) and the axis (2) on the two adjacent VBV door positions.

(8) Remove the nut (10), the washer (9), the bolt (7) and the spacer (8) from the VBV door (6).
(9) Remove the slave turnbuckle (11).
(10) Install the two previously removed OGV (Ref. AMM TASK 72-24-20-400-801).

[Rev.10 from 2021] 2026.04.01 02:53:31 UTC