W DOC AIRBUS | TSM A320F

Failure of the THS Actuator

TASK 27-40-00-810-807-A
Failure of the THS Actuator

1. Possible Causes
  • ACTUATOR-THS [9CE]
  • position transducer units
  • pitch trim actuator
2. Job Set-up Information
 A. Fixtures, Tools, Test and Support Equipment
REFERENCE
QTY
DESIGNATION
0U190360
1
PIN-RIGGING,THS ACTUATOR,MECHANICAL INPUT LEVER
98D27403000000
1
HOLDING TOOL-TRIM CTL LOWER SHAFT
 B. Referenced Information
REFERENCE
DESIGNATION
ISB 27-1164
AMM 27-41-00-210-001
Detailed Visual Inspection of the THS Mechanical Control
AMM 27-41-00-210-002
Visual Inspection of the Pitch-Trim Control Wheel Indicators
AMM 27-41-00-210-003
Visual Inspection and Lubrication of the Rear THS control cable (between FR71 and the THS actuator)
AMM 27-41-00-220-001
Check of the Cable Tension Regulator of the THS Trim Control (Pointer in the Limits)
AMM 27-41-00-720-001
Functional Test of the THS-Actuator Overtravel Related to the Mechanical Indicator
AMM 27-41-00-730-001
System Test of the THS Actuator Electrical Control
AMM 27-41-41-000-001
Removal of the Control Mechanism-Pitch Trim
AMM 27-41-41-400-001
Installation of the Control Mechanism-Pitch Trim
AMM 27-41-42-000-001
Removal of the Cable Tension Regulator
AMM 27-41-42-400-001
Installation of the Cable Tension Regulator
AMM 27-41-43-000-001
Removal of the Pitch Trim Control Stop and Gearset Unit
AMM 27-41-43-400-001
Installation of the Pitch Trim Control Stop and Gearset Unit
AMM 27-41-44-000-001
Removal of the THS Control Cables
AMM 27-41-44-400-001
Installation of the THS Control Cables
AMM 27-44-51-000-001
Removal of the Trimmable Horizontal Stabilizer (THS) Actuator
AMM 27-44-51-400-001
Installation of the Trimmable Horizontal Stabilizer (THS) Actuator
AMM 27-44-56-000-001
Removal of the Position Transducer from the THS Actuator
AMM 27-44-56-400-001
Installation of the Position Transducer to the THS Actuator
AMM 27-44-57-000-001
Removal of the Pitch Trim Actuator from the THS Actuator
AMM 27-44-57-400-001
Installation of the Pitch Trim Actuator to the THS Actuator
AMM 27-96-00-710-022
Operational Test of the THS Actuator Electrical Control (Activation for BITE Test)
AMM 27-96-00-740-001
BITE Test of the EFCS (Ground Scanning)
AMM 53-59-00-210-001
Operational Check of Single Drain Pipe Aft of FR70 from Outside
F THS Mechanical Control
3. Fault Confirmation
Subtask 27-40-00-700-062-A
A. Not Applicable
4. Fault Isolation
Subtask 27-40-00-810-056-A
A. Inspection of the upper and lower attachments of the THS actuator:
   (1) Do an inspection of the integrity of the load path (primary and secondary) at the upper and lower attachment of the THS actuator ISB 27-1164:
     (a) If the result of the inspection is not satisfactory:
     (b) If the result of the inspection is satisfactory:
       1 Do the operational test of the THS actuator electrical control AMM 27-96-00-710-022.
NOTE: Keep the Green and the Yellow hydraulic systems pressurized.
       2 Do the BITE test of the EFCS (ground scanning) AMM 27-96-00-740-001.
NOTE: Keep the Green and the Yellow hydraulic systems pressurized.
         a If the BITE test gives the maintenance messages:
THS ACTR POS ERROR 9CE OF ELAC2
THS ACTR POS ERROR 9CE OF ELAC1
THS ACTR POS ERROR 9CE OF SEC2
  • do the step 4.B.
         b If the BITE test does not give maintenance messages:
  • no maintenance action is necessary.
Subtask 27-40-00-810-061-A
B. Do a functional test of the THS actuator overtravel related to the mechanical indicator AMM 27-41-00-720-001:
NOTE: Keep the Green and the Yellow hydraulic systems pressurized.
   (1) If you do not find stiffness:
  • depressurized the Green and the Yellow hydraulic systems and do the step 4.C.
   (2) If you find stiffness:
     (a) Make sure that there is no water or ice in the lower area of the tail cone.
       1 If you find water or ice, remove it and make sure that the drain tube is not clogged AMM 53-59-00-210-001.
     (b) Disconnect the shaft (2) from the THS actuator (1) (see detail A):
F THS Mechanical Control
       1 Put the pitch-trim control wheel in the zero position.
       2 Put the 0U190360 PIN-RIGGING,THS ACTUATOR,MECHANICAL INPUT LEVER (8) in position on the THS actuator (1).
       3 Disconnect the mechanical system link-plate (7) from the input lever (9).
       4 Move the pitch-trim control wheel from one stop to the other and go back to the neutral position:
     (c) Disconnect the shaft (4) from the stop and gearset unit (5) (see detail B):
       1 Install the 98D27403000000 HOLDING TOOL-TRIM CTL LOWER SHAFT on the drive shaft (4).
       2 Install the standard locking bolt (10) on the chain (11).
       3 Remove the tapered pin (12).
       4 Move the pitch-trim control wheel from one stop to the other and go back to the neutral position:
  • if you do not find stiffness, go to Para. (e).
  • if you find stiffness, go to Para. (d).
     (d) Do a check for a failure of the mechanical part of the pitch-trim control mechanism (6) and the stop and gearset unit (5):
       1 Do this corrective action:
       2 Connect the shaft (4) to the stop and gearset unit (5):
  • install the tapered pin (12).
  • remove the standard locking bolt (10).
  • remove the trim-control lower shaft holding-tool.
       3 Connect the shaft (2) to the THS actuator (1):
  • connect the mechanical system link-plate (7) to the input lever (9).
  • remove the THS-actuator mechanical input lever rigging-pin (8).
       4 Go to the Para. (g).
     (e) Check of the cable tension regulator:
  • do a visual inspection of the cable tension regulator (3):
       1 Make sure that the cables are correctly installed in the pulleys.
       2 Make sure that the rigging scale index is in the correct position on the cable tension regulator.
       3 Do a check of the cable tension regulator of the THS trim control AMM 27-41-00-220-001:
  • if OK, go to Para. (f).
  • if not OK, do this corrective action:
         a Replace the cable tension regulator AMM 27-41-42-000-001 and AMM 27-41-42-400-001.
         b Connect the shaft (2) to the THS actuator (1):
  • connect the mechanical system link-plate (7) to the input lever (9).
  • remove the mechanical input lever rigging-pin (8).
         c Go to the Para. (g).
     (f) Check of the THS mechanical control:
       1 Remove the THS control cables AMM 27-41-44-000-001.
       2 Do a check of the bearings of the shafts (2) and (4).
       3 Install the THS control cables AMM 27-41-44-400-001.
       4 Connect the shaft (4) to the stop and gearset unit (5):
  • install the tapered pin (12).
  • remove the standard locking bolt (10).
  • remove the trim-control lower shaft holding-tool.
       5 Connect the shaft (2) to the THS actuator (1):
  • connect the mechanical system link-plate (7) to the input lever (9).
       6 Go to Para. (g).
     (g) Do a system test of the THS actuator electrical control AMM 27-41-00-730-001.
     (h) Do the operational test of the THS actuator electrical control AMM 27-96-00-710-022.
NOTE: Keep the Green and the Yellow hydraulic systems pressurized.
     (i) Do the BITE test of the EFCS (ground scanning) AMM 27-96-00-740-001.
NOTE: Keep the Green and the Yellow hydraulic systems pressurized.
       1 If the BITE test gives the maintenance messages:
THS ACTR POS ERROR 9CE OF ELAC2
THS ACTR POS ERROR 9CE OF ELAC1
THS ACTR POS ERROR 9CE OF SEC2
  • go to the Para. (j).
       2 If the BITE test does not give maintenance messages:
  • no maintenance action is necessary.
     (j) Move the pitch-trim control wheel from one stop to the other and go back to the neutral position:
Subtask 27-40-00-810-062-A
C. Replace the two position transducer units AMM 27-44-56-000-001 and AMM 27-44-56-400-001.
   (1) If the fault continues, replace the pitch trim actuator AMM 27-44-57-000-001 and AMM 27-44-57-400-001.
     (a) If the fault continues, replace the ACTUATOR-THS [9CE] AMM 27-44-51-000-001 and AMM 27-44-51-400-001.
[Rev.8 from Aug 2018] 2026.04.04 04:27:36 UTC
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