Installation of the Air Duct upstream of the Flow Control Unit

TASK 21-51-51-400-002-B
Installation of the Air Duct upstream of the Flow Control Unit

FIN: 23HB ** ON A/C NOT FOR ALL
FIN: 24HB ** 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	Torque wrench: range to between 0.5 and 0.4 m.daN (44.25 and 35.40 lbf.in )
No specific	Torque wrench: range to between 0.93 and 0.81 m.daN (82.30 and 71.68 lbf.in )

B. Work Zones and Access Panels

ZONE/ACCESS	ZONE DESCRIPTION
FOR [23HB] (FLOW CTL UNIT - PACK 1)
191BB, 191KB
FOR [24HB] (FLOW CTL UNIT - PACK 2)
192FB, 192KB

C. Expendable Parts

FIG.ITEM	DESIGNATION	IPC-CSN
11	SEAL	AIPC 21-51-03-11-090
27	WASHER	AIPC 21-52-03-84-080

D. Referenced Information

REFERENCE	DESIGNATION
TASK 12-33-21-618-001-A-01	Pre-conditioning through the HP Ground Connection
TASK 12-33-21-618-001-A-02	Pre-conditioning with the APU
TASK 20-28-00-912-802-A	Electrical Bonding - General Maintenance Procedure
TASK 21-61-00-710-001-A	Operational Test of the Pack Temperature-Control System
TASK 24-41-00-861-002-A	Energize the Aircraft Electrical Circuits from the External Power
TASK 24-41-00-861-002-A-01	Energize the Aircraft Electrical Circuits from the APU
TASK 24-41-00-861-002-A-02	Energize the Aircraft Electrical Circuits from Engine 1(2)
TASK 24-41-00-862-002-A	De-energize the Aircraft Electrical Circuits Supplied from the External Power
TASK 24-41-00-862-002-A-01	De-energize the Aircraft Electrical Circuits Supplied from the APU
TASK 24-41-00-862-002-A-02	De-energize the Aircraft Electrical Circuits Supplied from the Engine 1(2)
TASK 53-35-13-000-002-A	Removal of the Quick-Release Access Panels from the Belly Fairing Structure
TASK 53-35-13-400-002-A	Installation of the Quick-Release Access Panels on the Belly Fairing Structure
Attachment Components - Air Duct

3. Job Set-up
Subtask 21-51-51-860-053-A ** ON A/C NOT FOR ALL

A. Aircraft Maintenance Configuration
(1) Make sure that:
(a) The aircraft electrical circuits are energized (Ref. AMM TASK 24-41-00-861-002),
(b) On the panel 30VU:
1 The APU BLEED pushbutton switch is in the off position (the ON legend is off).
2 The ENG 1 BLEED and the ENG 2 BLEED pushbutton switches are in the off position (the OFF legends are on).
3 A warning notice is in position to tell persons not to operate these pushbutton switches.
(c) On the HP ground connector a warning notice is in position to tell persons not to supply the ground air.
(d) The access panels are removed (Ref. AMM TASK 53-35-13-000-002):
1 FOR [23HB] (FLOW CTL UNIT - PACK 1)
191KB and 191BB.
2 FOR [24HB] (FLOW CTL UNIT - PACK 2)
192KB and 192FB.

Subtask 21-51-51-865-067-A ** ON A/C NOT FOR ALL

B. Make sure that this(these) circuit breaker(s) is(are) open, safetied and tagged:

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C NOT FOR ALL
FOR FIN: 23HB (FLOW CTL UNIT PACK 1)
49VU	AIR COND/TEMP CTL/SYS 1 CHAN B/28VDC	52HH	D08
122VU	AIR COND/TEMP CTL SYS 1/CHAN A/115VAC	49HH	X22
122VU	AIR COND/TEMP CTL SYS 1/CHAN A/28VDC	51HH	X21
122VU	AIR COND/TEMP CTL SYS 1/CHAN B/115VAC	50HH	Y18
FOR FIN: 24HB (FLOW CTL UNIT PACK 2)
122VU	AIR COND/TEMP CTL SYS 2/CHAN A/115VAC	53HH	W22
122VU	AIR COND/TEMP CTL SYS 2/CHAN A/28VDC	55HH	W21
122VU	AIR COND/TEMP CTL SYS 2/CHAN B/28VDC	56HH	Y21
122VU	AIR COND/TEMP CTL SYS 2/CHAN B/115VAC	54HH	Y20

4. Procedure
Subtask 21-51-51-420-061-A ** ON A/C NOT FOR ALL

A. Installation of the Attachment Components

Attachment Components - Air Duct ** ON A/C NOT FOR ALL

(1) Put the support rods (5) in position on the brackets (22) and install the bushings (21), the bolts (20), the washers (23) and the nuts (24).

Subtask 21-51-51-420-062-A ** ON A/C NOT FOR ALL

B. Installation of the Air Duct
(1) Remove the protective covers from the air duct assembly.
(2) Clean the component interfaces and/or the adjacent area.
(3) Put a new AIPC 21-51-03-11-090 SEAL (11) in position on the air duct flange.
(4) Put the air duct assembly in its correct position and attach the v-clamps (12) and (13) but do not tighten the clamps.
(5) Put the support rods (5) in position on the brackets (6).
(6) Install the bolts (7), the washers (9) and the nuts (10).
(7) TORQUE the clamp (12) to between 0.93 and 0.81 m.daN (82.30 and 71.68 lbf.in )

.
(8) TORQUE the clamp (13) to between 0.5 and 0.4 m.daN (44.25 and 35.40 lbf.in )

.
(9) Put the bonding strap (4) in position and install the bolt (3), the washer (2) and the nut (1) (Ref. AMM TASK 20-28-00-912-802).

Subtask 21-51-51-220-059-A ** ON A/C NOT FOR ALL

C. Post Installation Measurement and Adjustment
(1) At the sleeve (24):

make sure that the dimension X is 160.5 +3.5 mm or -3.5 mm (6.3189 +0.1378 in. or -0.1378 in.).

(2) At the support rod (5):

make sure that the dimension V between the support rod (5) and the bracket (22) is 1.2 mm (0.0472 in.) minimum.

(3) If necessary adjust the support-rods to get the correct dimensions V and X:

NOTE: Normally it is only necessary to adjust the aft support rod.

(a) Bend the tab washer (27) away from the lock-nut (26).
(b) Loosen the lock-nut (26).
(c) Remove the rod eye (25) and install a new AIPC 21-52-03-84-080 WASHER (27) on the rod eye thread.
(d) Install the rod eye (25).
(e) Turn the rod eye (25) clockwise or counterclockwise until:

the dimensions V and X are in the correct limits and
the bolt (7) can still easily be installed.

(f) Make sure that the threads of the rod eye (25) are deep enough in the support rod (5).

NOTE: If you cannot push a needle or equivalent through the inspection hole, then rod eye is deep enough in the support rod.

(g) Tighten the lock-nut (26).
(h) Bend the tab washer (27) to safety the lock-nut (26).

Subtask 21-51-51-865-068-A ** ON A/C NOT FOR ALL

D. Make sure that this(these) circuit breaker(s) is(are) closed:

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C NOT FOR ALL
FOR FIN: 23HB (FLOW CTL UNIT PACK 1)
49VU	AIR COND/TEMP CTL/SYS 1 CHAN B/28VDC	52HH	D08
122VU	AIR COND/TEMP CTL SYS 1/CHAN A/115VAC	49HH	X22
122VU	AIR COND/TEMP CTL SYS 1/CHAN A/28VDC	51HH	X21
122VU	AIR COND/TEMP CTL SYS 1/CHAN B/115VAC	50HH	Y18
FOR FIN: 24HB (FLOW CTL UNIT PACK 2)
122VU	AIR COND/TEMP CTL SYS 2/CHAN A/115VAC	53HH	W22
122VU	AIR COND/TEMP CTL SYS 2/CHAN A/28VDC	55HH	W21
122VU	AIR COND/TEMP CTL SYS 2/CHAN B/28VDC	56HH	Y21
122VU	AIR COND/TEMP CTL SYS 2/CHAN B/115VAC	54HH	Y20

Subtask 21-51-51-710-054-A ** ON A/C NOT FOR ALL

E. Test
(1) Do the pre-conditioning through the HP ground connector (Ref. AMM TASK 12-33-21-618-001) or with the APU (Ref. AMM TASK 12-33-21-618-001).
(2) Do a leak check of the air duct connections.

NOTE: Minimum leakage is permitted. After the pack operates some minutes, the leakage of air will reduce because the seals have their correct operating temperature.

(3) After approx. 15 minutes stop the pre-conditioning (Ref. AMM TASK 12-33-21-618-001) or (Ref. AMM TASK 12-33-21-618-001).
(4) Do the operational test of the pack temperature control system (Ref. AMM TASK 21-61-00-710-001).

5. Close-up
Subtask 21-51-51-410-061-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 access panels (Ref. AMM TASK 53-35-13-400-002):
(a) FOR [23HB] (FLOW CTL UNIT - PACK 1)
191KB and 191BB.
(b) FOR [24HB] (FLOW CTL UNIT - PACK 2)
192KB and 192FB.

Subtask 21-51-51-862-054-A ** ON A/C NOT FOR ALL

B. De-energize the aircraft electrical circuits (Ref. AMM TASK 24-41-00-862-002).

[Rev.9 from 2019] 2026.04.02 06:11:23 UTC