Installation of the Fuel Filter Differential Pressure Switch [CFMB]

TASK 73-34-15-400-041-A
Installation of the Fuel Filter Differential Pressure Switch

WARNING: BE CAREFUL WHEN YOU USE CONSUMABLE MATERIALS. OBEY THE MATERIAL MANUFACTURER'S INSTRUCTIONS AND YOUR LOCAL REGULATIONS.

ZONE: 400
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 1M(3 FT)
No specific	AR	OHMMETER MULTIRANGE
No specific	AR	WARNING NOTICE(S)
No specific	Torque wrench: range to between 85 and 75 lbf.in (0.96 and 0.85 m.daN )
No specific	Torque wrench: range to between 135 and 125 lbf.in (1.53 and 1.41 m.daN )
No specific	Torque wrench: range to between 160 and 150 lbf.in (1.81 and 1.70 m.daN )

B. Consumable Materials

REFERENCE	DESIGNATION
(Material No.CP1041)	isopropyl alcohol
(Material No.CP2442)	engine oil
(Material No.CP2651)	sealant
(Material No.CP8001)	lockwire 0.032 in. (0.8 mm) dia.
(Material No.CP8002)	lockwire 0.032 in. (0.8 mm) dia
(Material No.14SBA1)	Textile-Lint free Cotton -

C. Work Zones and Access Panels

ZONE/ACCESS	ZONE DESCRIPTION
400	POWER PLANT, NACELLES AND PYLONS
FOR [1000EM1] (ENGINE-1)
437AL, 438AR
FOR [1000EM2] (ENGINE-2)
447AL, 448AR

D. Expendable Parts

FIG.ITEM	DESIGNATION	IPC-CSN
25	PACKINGS	AIPC 73-34-15-01-020

E. Referenced Information

REFERENCE	DESIGNATION
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 71-00-00-710-006-B	Minimum Idle Check
TASK 71-13-00-010-040-B	Opening of the Fan Cowl Doors
TASK 71-13-00-410-040-B	Closing of the Fan Cowl Doors
Fuel Filter Differential Pressure Switch

3. Job Set-up
Subtask 73-34-15-860-051-A ** ON A/C NOT FOR ALL

A. Aircraft Maintenance Configuration
(1) Make sure that the aircraft electrical circuits are energized (Ref. AMM TASK 24-41-00-861-002).
(2) 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.
(3) Make sure that the ENG/MASTER CONTROL SWITCH is in OFF position
(4) 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).
(5) Make sure that the ACCESS PLATFORM 1M(3 FT) is in position.

Subtask 73-34-15-865-058-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: 1000EM1 (ENGINE1)
49VU	FUEL/LP VALVE/MOT1/ENG1	1QG	A08
121VU	FUEL/LP VALVE/MOT2/ENG1	3QG	M25
FOR FIN: 1000EM2 (ENGINE2)
49VU	FUEL/LP VALVE/MOT1/ENG2	2QG	A09
121VU	FUEL/LP VALVE/MOT2/ENG2	4QG	M26

Subtask 73-34-15-865-059-A ** ON A/C NOT FOR ALL

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

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C NOT FOR ALL
FOR FIN: 1000EM1 (ENGINE1)
49VU	ENGINE/1/HP FUEL SOV	1KC1	A01
FOR FIN: 1000EM2 (ENGINE2)
49VU	ENGINE/2/HP FUEL SOV	1KC2	A02

Subtask 73-34-15-010-054-A ** ON A/C NOT FOR ALL

D. Make sure that the fan cowl doors are open (Ref. AMM TASK 71-13-00-010-040):
(1) FOR [1000EM1] (ENGINE-1)
437AL 438AR
(2) FOR [1000EM2] (ENGINE-2)
447AL 448AR

4. Procedure
Subtask 73-34-15-420-050-A ** ON A/C NOT FOR ALL

A. Installation of the Fuel Filter Differential Pressure Switch

WARNING: BE CAREFUL WHEN YOU USE CONSUMABLE MATERIALS. OBEY THE MATERIAL MANUFACTURER'S INSTRUCTIONS AND YOUR LOCAL REGULATIONS.

(1) To be sure of a good electrical bond between the pressure switch (20) and the bracket, clean the mating surfaces with isopropyl alcohol (Material No.CP1041) and Textile-Lint free Cotton - (Material No.14SBA1) .
(2) Remove the protective covers from electrical connector 4000EL-A, the pressure switch (20) and the tube coupling nuts.
(3) Lubricate the packing:

WARNING: BE CAREFUL WHEN YOU USE CONSUMABLE MATERIALS. OBEY THE MATERIAL MANUFACTURER'S INSTRUCTIONS AND YOUR LOCAL REGULATIONS.

(a) Lubricate the AIPC 73-34-15-01-020 PACKINGS (25) with engine oil (Material No.CP2442) .
(4) Install the AIPC 73-34-15-01-020 PACKINGS (25) and the unions (30) in the pressure switch (20). TORQUE the unions to between 135 and 125 lbf.in (1.53 and 1.41 m.daN )

.
(5) Attach the pressure switch (20) to the bracket with the bolts (10) and the washers (15). TORQUE the bolts to between 85 and 75 lbf.in (0.96 and 0.85 m.daN )

.
(6) Install the tubes:

CAUTION: USE A SECOND WRENCH TO APPLY COUNTER TORQUE TO THE UNIONS ON THE PRESSURE SWITCH WHEN YOU CONNECT THE TUBES.

(a) Connect the tubes to the unions (30). TORQUE the coupling nuts to between 160 and 150 lbf.in (1.81 and 1.70 m.daN )

.
(7) Install the insulation housing (5) on the pressure switch (20).
(8) Put a loop of CP8001lockwire 0.032 in. (0.8 mm) dia. or CP8002lockwire 0.032 in. (0.8 mm) dia around the capstan. Twist the lockwire around the insulation housing (5) and attach it to the capstan on the opposite side.

NOTE: Do not tighten the lockwire more than necessary to hold the insulation housing in position on the pressure switch.

(9) Connect electrical connector 4000EL-A to the pressure switch (20). Tighten the connector by hand plus one-eighth turn.
(10) Do an electrical bond resistance check as follows:

NOTE: Make sure you do an electrical bond resistance check at each bolt location.

(a) Put one lead of the OHMMETER MULTIRANGE on the flange of the pressure switch (20) near the bolt (10).
(b) Put the other lead of the ohmmeter on the surface of the bracket.
(c) The resistance measured between the ohmmeter leads must not be more than 0.0025 ohm. Do two more checks.
(d) If the resistance is more than 0.0025 ohm, remove the pressure switch (20) and clean the mating surfaces again. Do this procedure until the resistance is less than 0.0025 ohm.
(11) Seal the electrical bond surfaces as follows:
(a) Clean the area around the boltheads and the surface of the bracket with a clean lint-free cloth.
(b) Mix sealant (Material No.CP2651) . Refer to the manufacturer's instructions.
(c) Apply a layer of the sealant between 0.010 in. (0.25 mm) and 0.020 in. (0.51 mm) thick around each bolthead, the pressure switch flange and around the mating surface of the bracket.
(d) Cure the sealant. Refer to the manufacturer's instructions.

5. Close-up
Subtask 73-34-15-869-052-A ** ON A/C NOT FOR ALL

A. Make sure that the work area is clean and clear of tools and other items.

Subtask 73-34-15-942-050-A ** ON A/C NOT FOR ALL

B. Remove the WARNING NOTICE(S).

Subtask 73-34-15-865-065-A ** ON A/C NOT FOR ALL

C. Remove the safety clip(s) and the tag(s) and close this(these) circuit breaker(s):

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C NOT FOR ALL
FOR FIN: 1000EM1 (ENGINE1)
49VU	FUEL/LP VALVE/MOT1/ENG1	1QG	A08
121VU	FUEL/LP VALVE/MOT2/ENG1	3QG	M25
FOR FIN: 1000EM2 (ENGINE2)
49VU	FUEL/LP VALVE/MOT1/ENG2	2QG	A09
121VU	FUEL/LP VALVE/MOT2/ENG2	4QG	M26

Subtask 73-34-15-710-050-A ** ON A/C NOT FOR ALL

D. Do a minimum idle check (Ref. AMM TASK 71-00-00-710-006) and a check for leaks.

Subtask 73-34-15-410-050-A ** ON A/C NOT FOR ALL

E. Close Access
(1) Close the fan cowl doors (Ref. AMM TASK 71-13-00-410-040):
(a) FOR [1000EM1] (ENGINE-1)
437AL 438AR
(b) FOR [1000EM2] (ENGINE-2)
447AL 448AR
(2) Remove the access platform(s).

Subtask 73-34-15-862-051-A ** ON A/C NOT FOR ALL

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

[Rev.10 from 2021] 2026.04.01 02:59:57 UTC