Manual Adjustment of the Position Pick-Off Units
TASK 27-51-00-820-001-A
Manual Adjustment of the Position Pick-Off Units
To set the mechanical zero position of the Position Pick-off Units.
2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment
B. Referenced Information
3. Job Set-up
Subtask 27-51-00-941-072-A
Subtask 27-51-00-410-058-A
[Rev.10 from 2021]
2026.03.31 23:52:19 UTC
Manual Adjustment of the Position Pick-Off Units
WARNING:
PUT THE SAFETY DEVICES AND THE WARNING NOTICES IN POSITION BEFORE YOU START A TASK ON OR NEAR:
1. Reason for the Job- THE FLIGHT CONTROLS
- THE FLIGHT CONTROL SURFACES
- THE LANDING GEAR AND THE RELATED DOORS
- COMPONENTS THAT MOVE.
To set the mechanical zero position of the Position Pick-off Units.
2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment
| REFERENCE | QTY | DESIGNATION |
|---|---|---|
| No specific | 1 | LABEL - ADHESIVE, INOP |
| No specific | AR | SAFETY BARRIER(S) |
| No specific | 1 | TIE WRAP(S) |
| No specific | AR | WARNING NOTICE(S) |
| REFERENCE | DESIGNATION |
|---|---|
| TASK 27-51-18-000-001-A | Removal of the Asymmetry-Position Pick-Off Unit |
| TASK 27-51-18-400-001-A | Installation of the Asymmetry-Position Pick-Off Unit |
| TASK 27-51-19-000-001-A | Removal of the Feed Back Position Pick-Off Unit |
| TASK 27-51-19-400-001-A | Installation of the Feed Back Position Pick-Off Unit |
| TASK 27-55-11-000-001-A | Removal of the Instrumentation Position Pick-Off Unit |
| TASK 27-55-11-400-001-A | Installation of the Instrumentation Position Pick-Off Unit |
| TASK 27-81-18-000-001-A | Removal of the Asymmetry-Position Pick-Off Unit |
| TASK 27-81-18-400-001-A | Installation of the Asymmetry-Position Pick-Off Unit |
| TASK 27-81-19-000-001-A | Removal of the Feed Back Position Pick-Off Unit |
| TASK 27-81-19-400-001-A | Installation of the Feed Back Position Pick-Off Unit |
| TASK 27-85-11-000-001-A | Removal of the Instrumentation Position Pick-Off Unit |
| TASK 27-85-11-400-001-A | Installation of the Instrumentation Position Pick-Off Unit |
Subtask 27-51-00-941-072-A
A. Safety Precautions
(1) Put the SAFETY BARRIER(S) in position.
(2) Put a WARNING NOTICE(S) in position to tell persons not to operate the flight controls.
Subtask 27-51-00-010-060-A (1) Put the SAFETY BARRIER(S) in position.
(2) Put a WARNING NOTICE(S) in position to tell persons not to operate the flight controls.
B. Get Access
(1) Remove the applicable Position Pick-off Unit (PPU):
4. Procedure(1) Remove the applicable Position Pick-off Unit (PPU):
- for the Asymmetry-Position Pick-Off Unit (APPU) (Ref. AMM TASK 27-51-18-000-001)
- for the Feed-Back Position Pick-Off Unit (FPPU) (Ref. AMM TASK 27-51-19-000-001)
- for the Instrumentation Position Pick-Off Unit (IPPU) (Ref. AMM TASK 27-55-11-000-001)
- for the Asymmetry-Position Pick-Off Unit (APPU) (Ref. AMM TASK 27-81-18-000-001)
- for the Feed-Back Position Pick-Off Unit (FPPU) (Ref. AMM TASK 27-81-19-000-001)
- for the Instrumentation Position Pick-Off Unit (IPPU) (Ref. AMM TASK 27-85-11-000-001).
CAUTION:
BE CAREFUL WHEN YOU DO MAINTENANCE TASKS ON THE WING TRAILING EDGE:
Subtask 27-51-00-820-050-A - DO NOT CAUSE DAMAGE TO THE ELECTRICAL CABLE RACEWAYS.
- DO NOT CAUSE DAMAGE TO THE ELECTRICAL CABLE INSTALLATIONS.
- MAKE SURE THAT THE ELECTRICAL CABLES ARE INSTALLED CORRECTLY. INCORRECT INSTALLATION CAN CAUSE DAMAGE.
A. Manual Adjustment of the Position Pick-Off Units
(1) Unlock the locking plate of the drive shaft of the PPU.
(2) Make sure that the drive shaft turns freely.
(3) Turn the input shaft and align the drive gear zero mark and the orange zero indicator with the fixed pointers.
(4) Make sure that the input shaft zero mark and the fixed zero mark are aligned.
(a) Install a TIE WRAP(S) behind the locking plate.
(b) Attach a LABEL - ADHESIVE, INOP to the PPU to tell persons that the PPU is locked in the zero position.
5. Close-up(1) Unlock the locking plate of the drive shaft of the PPU.
(2) Make sure that the drive shaft turns freely.
(3) Turn the input shaft and align the drive gear zero mark and the orange zero indicator with the fixed pointers.
(4) Make sure that the input shaft zero mark and the fixed zero mark are aligned.
NOTE: The mechanical zero position and the electrical zero position are the same.
(5) If the PPU is not to be immediately installed: (a) Install a TIE WRAP(S) behind the locking plate.
(b) Attach a LABEL - ADHESIVE, INOP to the PPU to tell persons that the PPU is locked in the zero position.
Subtask 27-51-00-410-058-A
A. Close Access
(1) Make sure that the work area is clean and clear of tools and other items.
(2) Install the applicable Position Pick-off Unit (PPU):
Subtask 27-51-00-942-076-A (1) Make sure that the work area is clean and clear of tools and other items.
(2) Install the applicable Position Pick-off Unit (PPU):
- for the Asymmetry-Position Pick-Off Unit (APPU) (Ref. AMM TASK 27-51-18-400-001)
- for the Feed-Back Position Pick-Off Unit (FPPU) (Ref. AMM TASK 27-51-19-400-001)
- for the Instrumentation Position Pick-Off Unit (IPPU) (Ref. AMM TASK 27-55-11-400-001)
- for the Asymmetry-Position Pick-Off Unit (APPU) (Ref. AMM TASK 27-81-18-400-001)
- for the Feed-Back Position Pick-Off Unit (FPPU) (Ref. AMM TASK 27-81-19-400-001)
- for the Instrumentation Position Pick-Off Unit (IPPU) (Ref. AMM TASK 27-85-11-400-001).
B. Removal of Equipment
(1) Remove the safety barriers.
(2) Remove the WARNING NOTICE(S).
(3) Remove the ground support and maintenance equipment, the special and standard tools and all other items.
(1) Remove the safety barriers.
(2) Remove the WARNING NOTICE(S).
(3) Remove the ground support and maintenance equipment, the special and standard tools and all other items.
Position Pick-off Unit