Installation of the Asymmetry-Position Pick-Off Unit

TASK 27-81-18-400-001-A
Installation of the Asymmetry-Position Pick-Off Unit

WARNING: MAKE SURE THAT THE FLIGHT CONTROL SAFETY-LOCKS AND THE WARNING NOTICES ARE IN POSITION.

WARNING: MAKE SURE THAT THE GROUND SAFETY-LOCKS ARE IN POSITION ON THE LANDING GEAR. THIS WILL PREVENT UNWANTED MOVEMENT OF THE LANDING GEAR, AND THUS POSSIBLE INJURY TO PERSONS AND DAMAGE TO THE AIRCRAFT AND/OR EQUIPMENT.

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

ZONE: 522
ZONE: 622
FIN: 31CV
FIN: 32CV

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 4M (13 FT)
No specific	AR	SAFETY BARRIER(S)
No specific	AR	WARNING NOTICE(S)
No specific	Torque wrench: range to between 0.96 and 0.78 m.daN (84.96 and 69.03 lbf.in )
98D27803500001	1	LOCKING TOOL ZERO POS
98D27803500002	1	LOCKING TOOL ZERO POS

B. Consumable Materials

REFERENCE	DESIGNATION
(Material No.08BAA9)	Non Aqueous Cleaner-General - -
(Material No.12ACC1)	Corrosion Preventive Compound-Heavy Duty Soft Film -
(Material No.14SBA1)	Textile-Lint free Cotton -

C. Work Zones and Access Panels

ZONE/ACCESS	ZONE DESCRIPTION
522	OUTBOARD FIXED L.E STRUCTURE
622	OUTBOARD FIXED L.E STRUCTURE
522UB, 622UB
FOR [31CV] (POSITION PICK OFF UNIT)
522UB
FOR [32CV] (POSITION PICK OFF UNIT)
622UB

D. Referenced Information

REFERENCE	DESIGNATION
TASK 20-28-00-912-802-A	Electrical Bonding - General Maintenance Procedure
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
Asymmetry-Position Pick-Off Unit 31CV (32CV)

3. Job Set-up
Subtask 27-81-18-941-056-A

A. Safety Precautions

WARNING: BEFORE YOU START WORK, YOU MUST PUT ON A SAFETY HARNESS AND ATTACH IT TO THE ACCESS PLATFORM. WITHOUT A SAFETY HARNESS, YOU CAN FALL. THIS CAN KILL YOU OR CAUSE YOU INJURY.

(1) Make sure that the SAFETY BARRIER(S) are in position.
(2) Make sure that the WARNING NOTICE(S) are in position to tell persons not to operate the slat system.

Subtask 27-81-18-860-051-A

B. Aircraft Maintenance Configuration

WARNING: MAKE SURE THAT THE TRAVEL RANGES OF THE FLIGHT CONTROLS SURFACES ARE CLEAR. MOVEMENT OF FLIGHT CONTROLS CAN CAUSE INJURY TO PERSONS AND/OR DAMAGE TO EQUIPMENT.

(1) Make sure that the slats are fully retracted, if the APPU is a replacement (Ref. AMM TASK 27-80-00-866-005).
(2) Make sure that the 98D27803500001 LOCKING TOOL ZERO POS or 98D27803500002 LOCKING TOOL ZERO POS is installed on the flap/slat control lever.
(3) Make sure that the applicable access panel is removed:
(a) For the left wing, the access panel 522UB.
(b) For the right wing, the access panel 622UB.

Subtask 27-81-18-865-051-A

C. 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/WTB/SLT/SYS2	11CV	P19
121VU	FLIGHT CONTROLS/SLT/CTL/SYS2	7CV	R21
122VU	FLIGHT CONTROLS/WTB/SLT/SYS1	9CV	S06

4. Procedure
Subtask 27-81-18-420-051-A

A. Preparation for Installation
(1) Use a Textile-Lint free Cotton - (Material No.14SBA1) made moist with Non Aqueous Cleaner-General - - (Material No.08BAA9) to clean the:

interface of the APPU (5)
adaptor plate (12)
bolts (6)
washers (7).

(2) Make sure that the parts retained from the removed component are clean and in the correct condition.
(3) Do an inspection of the component interfaces and the adjacent area.
(4) Examine the APPU (5) and the interface of the adaptor plate (12) for damage, cracks and corrosion.
(5) If you install a new APPU (5) make sure that:
(a) The zero marks, in the viewing window, align with their applicable fixed pointers (Detail D).
(b) The zero marks, on the drive shaft (10) and the APPU (5), align with each other (Detail C).

Subtask 27-81-18-420-052-B

B. Installation of the Asymmetry-Position Pick-Off Unit (APPU)

CAUTION: MAKE SURE THAT THE SYSTEM IS IN ITS ZERO DEGREE POSITION BEFORE YOU INSTALL THE APPU. A NEW APPU IS SUPPLIED LOCKED IN THE MECHANICAL AND ELECTRICAL ZERO POSITION.

(1) Remove the tie-wrap (8) from behind the locking plate (11).
(2) Install the bonding strap (13) with the washer (2) and screw (1) (Ref. AMM TASK 20-28-00-912-802).
(3) Install the APPU:

CAUTION: DO NOT USE THE INSTALLATION BOLTS TO ENGAGE THE APPU DRIVE IN THE COUPLING. IF YOU DO, THIS WILL CAUSE:

THE COUPLING TO DISCONNECT
DAMAGE TO THE SPLINES
DAMAGE TO THE APPU.

(a) Position the APPU (5) on the adaptor plate (12). Make sure that the housing keyway and the key in the adaptor plate (12) align correctly.
(b) Engage the APPU drive shaft (10) in the splines of the bellows coupling (9).
(c) Use hand pressure and carefully push the APPU (5) fully into the adaptor plate (12). Hold the APPU (5) in this position and install the washers (7) and the bolts (6).
(d) TORQUE the bolts (6) to between 0.96 and 0.78 m.daN (84.96 and 69.03 lbf.in )

.
(4) Apply a layer of Corrosion Preventive Compound-Heavy Duty Soft Film - (Material No.12ACC1) to the bolts (6) and washers (7).
(5) Remove the blanking caps from the plugs (3) and (4) and the connectors A and B.
(6) Electrically connect the APPU:

CAUTION: REFER TO THE MATCH MARKS MADE DURING THE REMOVAL WHEN YOU CONNECT THE ELECTRICAL WIRES. INCORRECT CONNECTION OF THE WIRES WILL CAUSE DAMAGE TO EQUIPMENT.

(a) Connect the plug (3) to connector A and the plug (4) to connector B.
(7) Make sure that the slat movement area is clear of tools, materials and equipment.
(8) Remove the 98D27803500001 LOCKING TOOL ZERO POS or 98D27803500002 LOCKING TOOL ZERO POS from the flap/slat control-lever.

Subtask 27-81-18-865-052-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/WTB/SLT/SYS2	11CV	P19
121VU	FLIGHT CONTROLS/SLT/CTL/SYS2	7CV	R21
122VU	FLIGHT CONTROLS/WTB/SLT/SYS1	9CV	S06

Subtask 27-81-18-740-050-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 27-81-18-820-050-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 27-81-18-710-050-A

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

5. Close-up
Subtask 27-81-18-410-050-A

A. Close Access
(1) Make sure that the work area is clean and clear of tools and other items.
(2) Install the safety collar on circuit breakers 9CV and 11CV.
(3) Put the ACCESS PLATFORM 4M (13 FT) in position, below the applicable access panel 522UB 622UB.
(4) Install the applicable access panel:
(a) FOR [31CV] (POSITION PICK OFF UNIT)
install the access panel 522UB.
(b) FOR [32CV] (POSITION PICK OFF UNIT)
install the access panel 622UB.

Subtask 27-81-18-942-051-A

B. Removal of Equipment
(1) Remove the access platform(s).
(2) Remove the safety barriers.
(3) Remove the WARNING NOTICE(S).
(4) Remove the ground support and maintenance equipment, the special and standard tools and all other items.

[Rev.10 from 2021] 2026.04.01 06:56:47 UTC