Adjustment/Test of the Fuel Metering Unit (FMU) - Convert the TRW Lucas FMU SBE 73-0173 [IAE]

TASK 73-22-52-700-011-A
Adjustment/Test of the Fuel Metering Unit (FMU) - Convert the TRW Lucas FMU SBE 73-0173

WARNING: BE CAREFUL NOT TO GET AIRCRAFT FUEL IN YOUR MOUTH OR IN YOUR EYES. IF YOU GET FUEL ON YOUR SKIN OR ON YOUR CLOTHES, FLUSH IT IMMEDIATELY WITH WATER. IF NECESSARY, GET MEDICAL HELP. AIRCRAFT FUEL IS POISONOUS.

CAUTION: DO NOT LET ENGINE FUEL OR OIL FALL ON THE ENGINE. UNWANTED FUEL OR OIL MUST BE REMOVED IMMEDIATELY WITH A CLEAN LINT FREE CLOTH. THE FUEL OR OIL CAN CAUSE DAMAGE TO THE SURFACE PROTECTION AND TO SOME PARTS.

CAUTION: REFER TO SBE 72-0285 IF THIS SWITCHING TASK IS DONE AS PART OF AN ENGINE RE-RATING EXERCISE. SBE 72-0285 : ENGINE CONVERSION - PROVIDE INSTRUCTIONS TO CHANGE THE V2500-A5 ENGINE RATING BY MODIFYING THE DATA ENTRY PLUG.

FIN: 4000KC ** 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	WARNING NOTICE(S)
No specific	Torque wrench: range to between 22 and 18 lbf.in (0.25 and 0.20 m.daN )

B. Consumable Materials

REFERENCE	DESIGNATION
(Material No.V02-126)	lockwire

C. Work Zones and Access Panels

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

D. Referenced Information

REFERENCE	DESIGNATION
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 73-22-00-710-040-A	Operational Test of the FADEC SYSTEM on the Ground
TASK 73-22-52-400-010-B	Installation of the Fuel Metering Unit (FMU)
TASK 73-31-17-400-010-B	Installation of the Fuel Flow Transmitter
TASK 80-13-51-710-040-B	Operational Test of the Pneumatic Starter Valve and FMU with the CFDS
TRW Lucas FMU Adjust the Max. Fuel Flow Stop
TRW Lucas FMU Adjust the Max. Fuel Flow Stop - Safety Wire Procedures.

3. Job Set-up
Subtask 73-22-52-941-053-A ** ON A/C NOT FOR ALL

A. Safety Precautions
(1) On the center pedestal, on the ENG panel 115VU:
(a) Put a WARNING NOTICE(S) to tell persons not to start the engine.
(2) Make sure that the engine 1(2) shutdown occurred not less than 5 minutes before you do this procedure.
(3) On the overhead maintenance panel 50VU:
(a) Make sure that the ON legend of the ENG/FADEC GND PWR/1(2) pushbutton switch is off.
(b) Put a WARNING NOTICE(S) to tell persons not to energize the FADEC 1(2).

Subtask 73-22-52-010-057-A ** ON A/C NOT FOR ALL

B. Open the fan cowls (Ref. AMM TASK 71-13-00-010-010):
(1) FOR [1000EM1] (ENGINE-1)
437AL 438AR
(2) FOR [1000EM2] (ENGINE-2)
447AL 448AR

4. Procedure
Subtask 73-22-52-020-060-A ** ON A/C NOT FOR ALL

A. Disconnect the engine harness from the FMU and flowmeter.
(1) Disconnect the engine harness from the FMU and flowmeter to provide sufficient space to work (Ref. AMM TASK 73-22-52-400-010) and (Ref. AMM TASK 73-31-17-400-010).

Subtask 73-22-52-730-051-A ** ON A/C NOT FOR ALL

WARNING: USE PROTECTIVE GOGGLES AND GLOVES WHEN YOU REMOVE OR INSTALL LOCKWIRE. EACH TIME YOU CUT LOCKWIRE, REMOVE AND DISCARD IT IMMEDIATELY. LOOSE LOCKWIRE CAN CUT YOU OR MAKE YOU BLIND, AND/OR CAN CAUSE DAMAGE.

CAUTION: YOU MUST NOT EXCEED THE RECOMMENDED TORQUE VALUES. OVER TORQUING CAN RESULT IN DAMAGE TO THE FUEL METERING UNIT (FMU) WHICH MAY NECESSITATE REPLACEMENT OF THE FMU.

B. Resetting procedure : Convert the TRW Lucas FMU Part Number FMU560MK1 to Part Number FMU570MK1.

TRW Lucas FMU Adjust the Max. Fuel Flow Stop ** ON A/C NOT FOR ALL

TRW Lucas FMU Adjust the Max. Fuel Flow Stop - Safety Wire Procedures. ** ON A/C NOT FOR ALL

(1) Before you change the setting make sure that the FMU part number and stop setting letter correctly match each other. Report mismatch to your local quantity representative.

-------------------------------------------------------------------------------

! FMU PART NUMBER ! POSITION SETTING LETTER !

!-------------------------------!---------------------------------------------!

! FMU 560 MK1 ! O !

!-------------------------------!---------------------------------------------!

! FMU 570 MK1 ! X !

-------------------------------------------------------------------------------

(2) Check that the secondary latch (1) is not unclipped before you start this procedure. Report mismatch to your local quality representative.
(3) Remove the lockwire and unclip the spring latch (1) from the housing.

CAUTION: DO NOT USE A SCREWDRIVER WITH A BLADE WIDTH OF MORE THAN 1/2 IN. (13 MM) AND A BLADE LENGTH OF MORE THAN 8 IN. (200 MM).

(4) Place a flatbladed screwdriver in the slot on the sleeve (visible through the housing window) and move the sleeve up fully.

NOTE: You can carefully use the edge of information plate (6) as a lever for the screwdriver.

(5) Keep the sleeve raised and at the same time use a 5/8 inch wrench to turn the exposed hexagon counterclockwise. After a small amount of turn, you can remove the screwdriver from the sleeve slot.

NOTE: Turn the exposed hexagon counterclockwise as viewed from the hexagon end of the device.

(6) Continue to rotate the sleeve hexagon (2) in an anti-clockwise (counterclockwise) direction until the device 'clicks' into the alternative setting position.
(7) Check the setting position. Make sure the sleeve hexagon (2) has returned to the fully down position into the housing and the position setting letter X is fully visible in the housing window.
(8) Clip the spring latch (1) down on the housing to safety it.
(9) Safety the spring latch and switchable datum assembly with lockwire.
(a) Use a single piece of lockwire (Material No.V02-126) and wrap the lockwire around the base of the hinge and the spring latch twice. Refer to stages 1 to 5 on the following illustration:

TRW Lucas FMU Adjust the Max. Fuel Flow Stop - Safety Wire Procedures. ** ON A/C NOT FOR ALL

(b) Make sure that the lockwire tail, length 0.708 in. to 0.866 in. (18mm to 22mm) is formed to the right of the maximum flow stop setting display window, stages 5 and 7.
(c) Make sure that the completed wire lock does not move more than 0.08 in. (2,0mm) in a direction which is parellel to the axis of the switchable datum assembly.
(d) Install the ferrule (8) on to the tail of the lockwire to touch the switchable datum assembly, refer to stage 6.
(e) Crimp the ferrule (8) on to the lockwire with a crimping tool which has a minimum jaw width of 0.393in. (10mm). Make sure that the thickness of the ferrule between the crimped faces is between 0.110in. and 0.098in. (2,8mm and 2,5mm).
(f) Bend the lockwire tail back towards the maximum flow stop assembly, refer to stage 7.
(10) Identify the FMU with the correct nameplate (4).
(a) Remove the lockwire from the retaining screws (3).
(b) Remove the two nameplate retaining screws (3) and remove the nameplate (4).
(c) Turn the nameplate (4) over to show P/N FMU 570 MK1 and install the two screws (3) to attach the nameplate (4) to the FMU.
(d) TORQUE the two screws to between 22 and 18 lbf.in (0.25 and 0.20 m.daN )

(11) Safety the nameplate retaining screws.
(a) Use one piece of lockwire (Material No.V02-126) and safety the two retaining screws to each other.
(b) Route the lockwire around the screw heads or as shown

TRW Lucas FMU Adjust the Max. Fuel Flow Stop - Safety Wire Procedures. ** ON A/C NOT FOR ALL

NOTE: The requirement to safety the screws with lockwire is to give a visual anti-tamper indication only. The two retaining screws are locked in position with self-locking wire thread inserts.

(c) Cut the lockwire tail to length between 0.708in. to 0.866in. (18mm to 22mm) from the retaining screw head.
(d) Install the ferrule (8) on to the tail of the lockwire to touch the retaining screw head.
(e) Crimp the ferrule (8) on to the lockwire. Use a crimping tool which has a minimum jaw width of 0.393in. (10mm).
(f) Make sure that the thickness of the ferrule between the crimped faces is between 0.110in. and 0.098in. (2,8mm and 2,5mm).
(g) Bend the lockwire tail towards the head of the retaining screw.
(12) Do the final checks.
(a) Inspect the nameplate (4), make sure you can see the P/N FMU 570MK1.
(b) Make sure the stop setting letter X is visible in the housing window.
(c) Make sure the spring latch (1) is locked down and fully engaged on the housing to safety it.
(d) Make sure that the two ferrules are correctly crimped and secure.
(e) Make sure the FMU serial number on the nameplate (4) and modification plate (5) are the same as each other.

Subtask 73-22-52-730-053-A ** ON A/C NOT FOR ALL

CAUTION: YOU MUST NOT EXCEED THE RECOMMENDED TORQUE VALUES. OVER TORQUING CAN RESULT IN DAMAGE TO THE FUEL METERING UNIT (FMU) WHICH MAY NECESSITATE REPLACEMENT OF THE FMU.

C. Resetting procedure : Convert the TRW Lucas FMU Part Number FMU 570MK1 to Part Number FMU 560MK1.

TRW Lucas FMU Adjust the Max. Fuel Flow Stop ** ON A/C NOT FOR ALL

TRW Lucas FMU Adjust the Max. Fuel Flow Stop - Safety Wire Procedures. ** ON A/C NOT FOR ALL

(1) Before you change the setting make sure that the FMU part number and stop setting letter correctly match each other. Report mismatch to your local quality representative.

FMU PART NUMBER	POSITION SETTING LETTER
FMU 560 MK1	O
FMU 570 MK1	X

(2) Check that the spring latch (1) is not unclipped before you start this procedure. Report mismatch to your local quality representative.
(3) Remove the lockwire and unclip the spring latch (1).

CAUTION: DO NOT USE A SCREWDRIVER WITH A BLADE WIDTH OF MORE THAN 1/2 IN. (13 MM) AND A BLADE LENGTH OF MORE THAN 8 IN. (200 MM).

(4) Place a flatbladed screwdriver in the slot on the sleeve (visible through the housing window) and move the sleeve up fully.

NOTE: You can carefully use the edge of information plate (6) as a lever for the screwdriver.

(5) Keep the sleeve raised and at the same time use a 5/8 inch wrench to turn the exposed hexagon clockwise. After a small amount of turn, you can remove the screwdriver from the sleeve slot.

NOTE: Turn the exposed hexagon clockwise as viewed from the hexagon end of the device.

(6) Continue to rotate the sleeve hexagon (2) in a clockwise direction until the device 'clicks' into the alternative setting position.
(7) Check the setting position. Make sure the sleeve hexagon (2) has returned to the fully down position into the housing and the position setting letter O is fully visible in the housing window.
(8) Clip the spring latch (1) down on the housing to safety it.
(9) Safety the spring latch and switchable datum assembly with lockwire.
(a) Use a single piece of lockwire (Material No.V02-126) and wrap the lockwire around the base of the hinge and the base of the spring latch twice. Refer to stages 1 to 5 on the following illustration:

TRW Lucas FMU Adjust the Max. Fuel Flow Stop - Safety Wire Procedures. ** ON A/C NOT FOR ALL

(b) Make sure that the lockwire tail, length 0.708 in. to 0.866 in. (18mm to 22mm) is formed to the right of the maximum flow stop setting display window, stages 5 and 7.
(c) Make sure that the completed wire lock does not move more than 0.08 in. (2,0mm) in a direction which is parallel to the axis of the switchable datum assembly.
(d) Install the ferrule (8) on to the tail of the lockwire to touch the switchable datum assembly, refer to stage 6.
(e) Crimp the ferrule (8) on to the lockwire with a crimping tool which has a minimum jaw width of 0.393 in. (10mm). Make sure that the thickness of the ferrule between the crimped faces is between 0.110 in. and 0.098 in. (2,8mm and 2,5mm).
(f) Bend the lockwire tail back towards the maximum flow stop assembly, refer to stage 7.
(10) Identify the FMU with the correct nameplate (4).
(a) Remove the lockwire from the retaining screws (3).
(b) Remove the two nameplate retaining screws (3) and remove the nameplate (4).
(c) Turn the nameplate (4) over to show P/N FMU 560 MK1 and install the two screws (3) to attach the nameplate (4) to the FMU.
(d) TORQUE the two screws to between 22 and 18 lbf.in (0.25 and 0.20 m.daN )

.
(11) Safety the nameplate retaining screws.
(a) Use one piece of lockwire (Material No.V02-126) and safety the two retaining screws to each other.
(b) Route the lockwire around the screw heads or as shown on the following illustration:

TRW Lucas FMU Adjust the Max. Fuel Flow Stop - Safety Wire Procedures. ** ON A/C NOT FOR ALL

NOTE: The requirement to safety the screws with lockwire is to give a visual anti-tamper indication only. The two retaining screws are locked in position with self-locking wire thread inserts.

(c) Cut the lockwire tail to length between 0.708 in. to 0.866 in. (18mm to 22mm) from the retaining screw head.
(d) Install the ferrule (8) on to the tail of the lockwire to touch the retaining screw head.
(e) Crimp the ferrule (8) on to the lockwire. Use a crimping tool which has a minimum jaw width of 0.393 in. (10mm).
(f) Make sure that the thickness of the ferrule between the crimped faces is between 0.110 in. and 0.098 in. (2,8mm and 2,5mm).
(g) Bend the lockwire tail towards the head of the retaining screw.
(12) Do the final checks.
(a) Inspect the nameplate (4), make sure you can see the P/N FMU 560MK1.
(b) Make sure the stop setting letter O is visible in the housing window.
(c) Make sure the spring latch (1) is locked down and fully engaged on the housing to safety it.
(d) Make sure that the two ferrules are correctly crimped and secure.
(e) Make sure the FMU serial number on the nameplate (4) and modification plate (5) are the same as each other.

Subtask 73-22-52-420-060-A ** ON A/C NOT FOR ALL

D. Connect the engine harness to the FMU and flowmeter (Ref. AMM TASK 73-22-52-400-010) and (Ref. AMM TASK 73-31-17-400-010).

5. Close-up
Subtask 73-22-52-942-054-A ** ON A/C NOT FOR ALL

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

Subtask 73-22-52-710-051-A ** ON A/C NOT FOR ALL

B. Do the following tests:
(1) Do the operational test of the starter and FMU (Ref. AMM TASK 80-13-51-710-040).
(2) Do the operational FADEC test (Ref. AMM TASK 73-22-00-710-040).

[Rev.10 from 2021] 2026.04.01 03:01:28 UTC