Removal of the Variable Bleed Valve (VBV) Ducts [CFML]

TASK 72-24-80-000-801-A
Removal of the Variable Bleed Valve (VBV) Ducts

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	CAP - PROTECTION
No specific	AR	COVER - PROTECTION
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 72-24-01-000-801-A	Removal of Segment Shrouds 1 thru 5
TASK 72-24-06-000-801-A	Removal of the Shroud Junction Fitting
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
Variable Bleed Valve (VBV) Ducts

3. Job Set-up
Subtask 72-24-80-941-050-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 72-24-80-010-050-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 72-24-80-040-050-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 72-24-80-010-051-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 72-24-80-020-050-A

A. Removal of the Variable Bleed Valve (VBV) Ducts

CAUTION: DURING REMOVAL/INSTALLATION OF THE SEAL, BE CAREFUL WHEN YOU PULL THE RUBBER PINS TO DISENGAGE/ENGAGE THEM. IF YOU ARE NOT CAREFUL, YOU CAN BREAK THE RUBBER PINS.

(1) Removal of VBV duct 1 (2):
(a) Remove segment shroud 1 (1) (Ref. AMM TASK 72-24-01-000-801).
(b) Remove the VBV duct aft-seal (3) from VBV duct 1 (2).
(c) Remove the four screws (5) that attach VBV grid 1 (4) to VBV duct 1 (2).
(d) Remove VBV grid 1 (4) from VBV duct 1 (2).
(e) Remove the VBV duct 1 (2) from the fan hub (7).
(f) Remove the VBV duct forward-seal (6) from VBV duct 1 (2) if necessary.
(2) Removal of VBV duct 2 (11) and VBV duct 3 (19):
(a) Remove the junction shroud fitting (9) (Ref. AMM TASK 72-24-06-000-801).
(b) Remove segment shroud 2 (8) (Ref. AMM TASK 72-24-01-000-801).
(c) Remove the junction shroud fitting (10) (Ref. AMM TASK 72-24-06-000-801).
(d) Remove VBV duct 2 (11) with the rubber cap and the clamp assembled.
(e) Remove the VBV duct aft-seal (15) from VBV duct 2 (11).
(f) Remove the four screws (17) that attach VBV grid 2 (16) to VBV duct 2 (11).
(g) Remove VBV grid 2 (16) from VBV duct 2 (11).
(h) Remove VBV duct 2 (11) from the fan hub (7).
(i) Remove the VBV duct forward-seal (18) from VBV duct 2 (11) if necessary.
(j) Remove the VBV duct aft-seal (20) from VBV duct 3 (19).
(k) Remove the four screws (22) that attach VBV grid 3 (21) to VBV duct 3 (19).
(l) Remove VBV grid 3 (21) from VBV duct 3 (19).
(m) Remove VBV duct 3 (19) from the fan hub (7).
(n) Remove the VBV duct forward-seal (23) from VBV duct 3 (19) if necessary.
(3) Removal of VBV duct 4 (25):
(a) Remove segment shroud 3 (24) (Ref. AMM TASK 72-24-01-000-801).
(b) Loosen the screw (28) from the hose clamp (27) that attaches the air manifold (26) to VBV duct 4 (25).
(c) Disconnect the air manifold (26) from VBV duct 4 (25).
(d) Remove the hose clamp (27) from VBV duct 4 (25).
(e) Remove the VBV duct aft-seal (29) from VBV duct 4 (25).
(f) Remove the four screws (31) that attach VBV grid 4 (30) to VBV duct 4 (25).
(g) Remove VBV grid 4 (30) from VBV duct 4 (25).
(h) Remove VBV duct 4 (25) from the fan hub (7).
(i) Remove the VBV duct forward-seal (32) from VBV duct 4 (25) if necessary.
(4) Removal of VBV duct 5 (34):
(a) Remove the segment shroud 4 (33) (Ref. AMM TASK 72-24-01-000-801).
(b) Remove the VBV duct aft-seal (35) from VBV duct 5 (34).
(c) Remove the four screws (37) that attach VBV grid 5 (36) to VBV duct 5 (34).
(d) Remove VBV grid 5 (36) from VBV duct 5 (34).
(e) Remove VBV duct 5 (34) from the fan hub (7).
(f) Remove the VBV duct forward-seal (38) from VBV duct 5 (34) if necessary.
(5) Removal of VBV duct 6 (40), VBV duct 7 (48) and VBV duct 8 (54):
(a) Remove segment shroud 5 (39) (Ref. AMM TASK 72-24-01-000-801).
(b) Loosen the screw (43) from the hose clamp (42) that attaches the core manifold (41) to VBV duct 6 (40).
(c) Disconnect the core manifold (41) from VBV duct 6 (40).
(d) Remove the hose clamp (42) from VBV duct 6 (40).
(e) Remove the VBV duct aft-seal (44) from VBV duct 6 (40).
(f) Remove the four screws (46) that attach VBV grid 6 (45) to VBV duct 6 (40).
(g) Remove VBV grid 6 (45) from VBV duct 6 (40).
(h) Remove VBV duct 6 (40) from the fan hub (7).
(i) Remove the VBV duct forward-seal (47) from VBV duct 6 (40) if necessary.
(j) Disconnect the manifold (49) from VBV duct 7 (48).
(k) Remove the VBV duct aft-seal (50) from VBV duct 7 (48).
(l) Remove the four screws (52) that attach VBV grid 7 (51) to VBV duct 7 (48).
(m) Remove VBV grid 7 (51) from VBV duct 7 (48).
(n) Remove VBV duct 7 (48) from the fan hub (7).
(o) Remove the VBV duct forward-seal (53) from VBV duct 7 (48) if necessary.
(p) Remove the VBV duct aft-seal (55) from VBV duct 8 (54).
(q) Remove the four screws (57) that attach VBV grid 8 (56) to VBV duct 8 (54).
(r) Remove VBV grid 8 (56) from VBV duct 8 (54).
(s) Remove VBV duct 8 (54) from the fan hub (7).
(t) Remove the VBV duct forward-seal (58) from VBV duct 8 (54) if necessary.
(u) Install the COVER - PROTECTION and the CAP - PROTECTION on all the open ports, open tubes, open hoses and disconnected connectors.

[Rev.10 from 2021] 2026.04.01 02:53:23 UTC