Installation of the Feed Back Position Pick-Off Unit

TASK 27-81-19-400-001-A
Installation of the Feed Back Position Pick-Off Unit

WARNING: PUT THE SAFETY DEVICES AND THE WARNING NOTICES IN POSITION BEFORE YOU START A TASK ON OR NEAR:

THE FLIGHT CONTROLS
THE FLIGHT CONTROL SURFACES
THE LANDING GEAR AND THE RELATED DOORS
COMPONENTS THAT MOVE.

MOVEMENT OF COMPONENTS CAN KILL OR CAUSE INJURY TO PERSONS AND/OR CAN CAUSE DAMAGE TO THE EQUIPMENT.

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

FIN: 28CV

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 3M (10 FT)- ADJUSTABLE
No specific	Torque wrench: range to between 0.96 and 0.87 m.daN (84.96 and 76.99 lbf.in )

B. Consumable Materials

REFERENCE	DESIGNATION
(Material No.06LCG9)	Non Hardening Jointing Putty-Medium Temp. Area - -
(Material No.08BAA9)	Non Aqueous Cleaner-General - -
(Material No.14SBA1)	Textile-Lint free Cotton -
(Material No.14VGE1)	Individual Compound-- Zinc Powder -
(Material No.666400)	ELECOLIT 414

C. 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 27-80-00-860-801-A	Readout of the Slat Position Pickoff Unit (PPU) Data
TASK 27-80-00-866-005-A	Retracting the Slats on the Ground
TASK 27-81-00-820-001-A	Manual Adjustment of the Position Pick-Off Units
TASK 27-84-00-710-001-A	Operational Test of the Slat System
TASK 32-12-00-010-001-A	Open the Main Gear Doors for Access
TASK 32-12-00-410-001-A	Close the Main Gear Doors after Access
Electrical Bonding Area of the FPPU
Feed Back Position Pick-Off Unit

3. Job Set-up
Subtask 27-81-19-860-051-A

A. Aircraft Maintenance Configuration
(1) Make sure that the main doors of the main gear are open (Ref. AMM TASK 32-12-00-010-001).
(2) Make sure that the ACCESS PLATFORM 3M (10 FT)- ADJUSTABLE is in position at the opening of the main door of the main gear.
(3) Make sure that the slats are in the retracted position (Ref. AMM TASK 27-80-00-866-005) because a new FPPU is delivered locked in its zero position.

Subtask 27-81-19-865-051-A

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
49VU	FLIGHT CONTROLS/SLT/CTL AND MONG/SYS1	5CV	B06
** ON A/C NOT FOR ALL
49VU	FLIGHT CONTROLS/SLT/CTL AND MONG/SYS1	5CV	B01
** ON A/C ALL
121VU	FLIGHT CONTROLS/SLT/CTL/SYS2	7CV	R21

4. Procedure
Subtask 27-81-19-860-052-A

A. Preparation for Installation

Electrical Bonding Area of the FPPU

(1) Do an inspection of the component interfaces and the adjacent area.
(2) Use a Textile-Lint free Cotton - (Material No.14SBA1) and the Non Aqueous Cleaner-General - - (Material No.08BAA9) to clean the:

mating area of the FPPU
mating area of the differential gearbox.

(3) Prepare a small quantity of a mixture of 58 % of Non Hardening Jointing Putty-Medium Temp. Area - - (Material No.06LCG9) and 42 % of Individual Compound-- Zinc Powder - (Material No.14VGE1) or use ELECOLIT 414 (Material No.666400) .
(4) Apply a quantity of the prepared mixture or apply Elecolit 414 to the related electrical bonding areas (refer to the related figure):
(a) Make sure that you apply the material on the mating areas on the FPPU and on the differential gearbox.
(5) Apply Non Hardening Jointing Putty-Medium Temp. Area - - (Material No.06LCG9) the threads of the screws (1).

Subtask 27-81-19-420-050-A

B. Installation of the FPPU

Feed Back Position Pick-Off Unit

(1) Make sure that all zero marks on the FPPU are aligned.
(2) Remove the tie-wrap (3).
(3) Install the FPPU carefully on the gearbox.
(4) Install the screws (1) and the washers (2).
(5) TORQUE the screws (1) to between 0.96 and 0.87 m.daN (84.96 and 76.99 lbf.in )

.
(6) Do a bonding test between the main bonding point of the power control unit and the FPPU flange. The resistance must not be more than 20 milliohms.
(7) Remove the blanking caps from the electrical connectors.
(8) Make sure that all the electrical connections are clean and in the correct condition.
(9) Connect the electrical connectors 28CV-A and 28CV-B to the FPPU.

Subtask 27-81-19-865-052-A

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
49VU	FLIGHT CONTROLS/SLT/CTL AND MONG/SYS1	5CV	B06
** ON A/C NOT FOR ALL
49VU	FLIGHT CONTROLS/SLT/CTL AND MONG/SYS1	5CV	B01
** ON A/C ALL
121VU	FLIGHT CONTROLS/SLT/CTL/SYS2	7CV	R21

Subtask 27-81-19-740-050-A

D. Do a Check of the Position Pick-Off Units (PPUs) on the Centralized Fault Display-System (CFDS)
(1) Energize the aircraft electrical circuits (Ref. AMM TASK 24-41-00-861-002).
(2) Do the readout and check of the PPU data (Ref. AMM TASK 27-80-00-860-801).
(3) De-energize the aircraft electrical circuits (Ref. AMM TASK 24-41-00-862-002).

Subtask 27-81-19-820-050-A

E. Adjustment
(1) If the PPU data are not in the limits:
Do the adjustment of the applicable PPU (Ref. AMM TASK 27-81-00-820-001).
(2) After the correct adjustment: Make sure that the PPU data are in the specified limits.

Subtask 27-81-19-710-050-A

F. Do the operational test of the slat system (Ref. AMM TASK 27-84-00-710-001).

5. Close-up
Subtask 27-81-19-410-050-A

A. Close Access
(1) Remove the access platform(s).
(2) Make sure that the work area is clean and clear of tools and other items.
(3) Close the main doors of the main gear (Ref. AMM TASK 32-12-00-410-001).

[Rev.10 from 2021] 2026.03.31 23:56:26 UTC