DOC AIRBUS | AMM A320FCheck the Backlash between the Ball Screw Nut and Screw of the THS-Actuator
TASK 27-44-51-200-001-A
Check the Backlash between the Ball Screw Nut and Screw of the THS-Actuator
Refer to the MPD TASK: 274451-07
2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment
B. Consumable Materials
C. Work Zones and Access Panels
D. Referenced Information
3. Job Set-up
Subtask 27-44-51-010-060-A
Subtask 27-44-51-220-052-A
Subtask 27-44-51-080-051-A Subtask 27-44-51-640-050-A
[Rev.8 from Aug 2017]
2026.03.31 23:51:38 UTC
Check the Backlash between the Ball Screw Nut and Screw of the THS-Actuator
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.
WARNING:
BE CAREFUL WHEN YOU USE CONSUMABLE MATERIALS. OBEY THE MATERIAL MANUFACTURER'S INSTRUCTIONS AND YOUR LOCAL REGULATIONS.
1. Reason for the Job2. 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 | 1 | GAGE - PUSH-PULL |
| No specific | AR | WARNING NOTICE(S) |
| 0U190863 | 1 | BACKLASH CHECKING TOOL-THS ACTUATOR |
| REFERENCE | DESIGNATION |
|---|---|
| (Material No.03HBD9) | Synthetic Ester base Grease-General Purpose Low Temp - |
| (Material No.08BBB1) | Non Aqueous Cleaner-- Petroleum Based - |
| (Material No.14SBA1) | Textile-Lint free Cotton - |
| ZONE/ACCESS | ZONE DESCRIPTION |
|---|---|
| 310 | FUSLG TAIL SECTION AFT OF AFT PRESS BHD |
| 312AR |
| REFERENCE | DESIGNATION |
|---|---|
| TASK 12-22-27-640-003-A | Lubrication of Trimmable Horizontal Stabilizer Actuator Ball Screw Nut |
| TASK 29-00-00-864-001-A | Put the Related Hydraulic System in the Depressurized Configuration before Maintenance Action |
THS Actuator Backlash CheckSubtask 27-44-51-010-060-A
A. Get Access
(1) Put the ACCESS PLATFORM 3M (10 FT)- ADJUSTABLE in position below the access door 312AR.
(2) Open the access door 312AR.
Subtask 27-44-51-860-052-A (1) Put the ACCESS PLATFORM 3M (10 FT)- ADJUSTABLE in position below the access door 312AR.
(2) Open the access door 312AR.
B. Aircraft Maintenance Configuration
(1) Make sure that the actuator for the Trimmable Horizontal Stabilizer is in the 0 degree position.
(2) Make sure that the Green hydraulic system is depressurized and put it in the maintenance configuration.
(Ref. AMM TASK 29-00-00-864-001).
(3) Make sure that the Yellow hydraulic system is depressurized and put it in the maintenance configuration.
(Ref. AMM TASK 29-00-00-864-001).
(4) Put warning notices on the ground service panels of the Green and Yellow hydraulic systems to tell persons not to pressurize the Green and Yellow hydraulic systems.
(5) Put WARNING NOTICE(S) in the cockpit to tell persons not to operate the pitch controls.
Subtask 27-44-51-865-055-A (1) Make sure that the actuator for the Trimmable Horizontal Stabilizer is in the 0 degree position.
(2) Make sure that the Green hydraulic system is depressurized and put it in the maintenance configuration.
(Ref. AMM TASK 29-00-00-864-001).
(3) Make sure that the Yellow hydraulic system is depressurized and put it in the maintenance configuration.
(Ref. AMM TASK 29-00-00-864-001).
(4) Put warning notices on the ground service panels of the Green and Yellow hydraulic systems to tell persons not to pressurize the Green and Yellow hydraulic systems.
(5) Put WARNING NOTICE(S) in the cockpit to tell persons not to operate the pitch controls.
C. Make sure that this(these) circuit breaker(s) is(are) open, safetied and tagged:
Subtask 27-44-51-480-051-A | PANEL | DESIGNATION | FIN | LOCATION |
|---|---|---|---|
| ** ON A/C ALL | |||
| 49VU | FLIGHT CONTROLS/ELAC1/NORM/SPLY | 15CE1 | B11 |
| 49VU | FLIGHT CONTROLS/THS/ACTR/MOT2 | 19CE2 | B09 |
| 105VU | FLT CTL/ELAC1/STBY SPLY | 16CE1 | A01 |
| 121VU | FLIGHT CONTROLS/THS ACTR/MOT3 | 19CE3 | Q17 |
| 121VU | FLIGHT CONTROLS/THS ACTR/MOT1 | 19CE1 | Q16 |
D. Install the 0U190863 BACKLASH CHECKING TOOL-THS ACTUATOR:
(1) Clean the screwshaft with a lint-free cloth Textile-Lint free Cotton - (Material No.14SBA1) and Non Aqueous Cleaner-- Petroleum Based - (Material No.08BBB1) and let it dry.
(2) Install the mechanical stop unit, part of the 0U190863 BACKLASH CHECKING TOOL-THS ACTUATOR, on the top side of the ballnut with the screws (1).
(3) Make sure that the cams of the mechanical stop unit engage with the cams of the ballnut.
(4) Make sure that the mechanical stop unit does not touch the thread of the screw shaft.
(5) Install the clamp and the lever assembly, parts of the 0U190863 BACKLASH CHECKING TOOL-THS ACTUATOR, on the top side of the mechanical stop unit to the thread of the screw shaft.
(6) Install the dial indicator part of the 0U190863 BACKLASH CHECKING TOOL-THS ACTUATOR on the screwshaft below the ballnut.
(7) Set the dial indicator to zero.
4. Procedure(1) Clean the screwshaft with a lint-free cloth Textile-Lint free Cotton - (Material No.14SBA1) and Non Aqueous Cleaner-- Petroleum Based - (Material No.08BBB1) and let it dry.
(2) Install the mechanical stop unit, part of the 0U190863 BACKLASH CHECKING TOOL-THS ACTUATOR, on the top side of the ballnut with the screws (1).
(3) Make sure that the cams of the mechanical stop unit engage with the cams of the ballnut.
(4) Make sure that the mechanical stop unit does not touch the thread of the screw shaft.
(5) Install the clamp and the lever assembly, parts of the 0U190863 BACKLASH CHECKING TOOL-THS ACTUATOR, on the top side of the mechanical stop unit to the thread of the screw shaft.
(6) Install the dial indicator part of the 0U190863 BACKLASH CHECKING TOOL-THS ACTUATOR on the screwshaft below the ballnut.
(7) Set the dial indicator to zero.
Subtask 27-44-51-220-052-A
A. Check of the Backlash
(1) With a GAGE - PUSH-PULL: Apply a force of 12 daN (27.0 lbf.) vertically (parallel to the screw shaft of the THS actuator) at the application hole of the lever assy of the 0U190863 BACKLASH CHECKING TOOL-THS ACTUATOR.
Make sure that the application hole is 385 mm (15.157 in.) away from the edge of the fitting fork.
(2) Use the dial indicator and make sure that the backlash is not more than 0.15 mm (0.006 in.).
5. Close-up(1) With a GAGE - PUSH-PULL: Apply a force of 12 daN (27.0 lbf.) vertically (parallel to the screw shaft of the THS actuator) at the application hole of the lever assy of the 0U190863 BACKLASH CHECKING TOOL-THS ACTUATOR.
Make sure that the application hole is 385 mm (15.157 in.) away from the edge of the fitting fork.
(2) Use the dial indicator and make sure that the backlash is not more than 0.15 mm (0.006 in.).
Subtask 27-44-51-080-051-A Subtask 27-44-51-640-050-A
B. Apply a small quantity of Synthetic Ester base Grease-General Purpose Low Temp - (Material No.03HBD9) to the screwshaft and lubricate the ball screw nut as necessary (Ref. AMM TASK 12-22-27-640-003).
Subtask 27-44-51-865-056-A C. Remove the safety clip(s) and the tag(s) and close this(these) circuit breaker(s):
Subtask 27-44-51-410-061-A | PANEL | DESIGNATION | FIN | LOCATION |
|---|---|---|---|
| ** ON A/C ALL | |||
| 49VU | FLIGHT CONTROLS/ELAC1/NORM/SPLY | 15CE1 | B11 |
| 49VU | FLIGHT CONTROLS/THS/ACTR/MOT2 | 19CE2 | B09 |
| 105VU | FLT CTL/ELAC1/STBY SPLY | 16CE1 | A01 |
| 121VU | FLIGHT CONTROLS/THS ACTR/MOT3 | 19CE3 | Q17 |
| 121VU | FLIGHT CONTROLS/THS ACTR/MOT1 | 19CE1 | Q16 |
D. Close Access
(1) Remove the WARNING NOTICE(S).
(2) Make sure that the work area is clean and clear of tools and other items.
(3) Close the access door 312AR.
(4) Remove the access platform(s).
(1) Remove the WARNING NOTICE(S).
(2) Make sure that the work area is clean and clear of tools and other items.
(3) Close the access door 312AR.
(4) Remove the access platform(s).