Detailed Inspection of THSA Lower Attachments for Primary and Secondary Load Path

TASK 27-44-51-220-003-A
Detailed Inspection of THSA Lower Attachments for Primary and Secondary Load Path

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: MAKE SURE THAT THE TRAVEL RANGES OF THE FLIGHT CONTROL SURFACES ARE CLEAR BEFORE YOU PRESSURIZE/DEPRESSURIZE A HYDRAULIC SYSTEM. IF YOU DO NOT OBEY THESE INSTRUCTIONS, THE MOVEMENT OF THE FLIGHT CONTROL SURFACES CAN CAUSE INJURY TO PERSONS AND DAMAGE TO EQUIPMENT.

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

CAUTION: ALWAYS OBEY THE PRECAUTIONS THAT FOLLOW TO KEEP ELECTRICAL WIRING IN A SATISFACTORY CONDITION (ELECTRICALLY AND MECHANICALLY SERVICEABLE). WHEN YOU DO MAINTENANCE WORK, REPAIRS OR MODIFICATIONS, ALWAYS KEEP ELECTRICAL WIRING, COMPONENTS AND THE WORK AREA AS CLEAN AS POSSIBLE. TO DO THIS:

PUT PROTECTION, SUCH AS PLASTIC SHEETING, CLOTHS, ETC. AS NECESSARY ON WIRING AND COMPONENTS.
REGULARLY REMOVE ALL SHAVINGS, UNWANTED MATERIAL AND OTHER CONTAMINATION

THESE PRECAUTIONS WILL DECREASE THE RISK OF CONTAMINATION AND DAMAGE TO THE ELECTRICAL WIRING INSTALLATION. IF THERE IS CONTAMINATION, REFER TO ESPM 20-55-00.

ZONE: 310
FIN: 9CE

1. Reason for the Job
Refer to the MPD TASK: 274451-10
DETAILED INSPECTION OF THSA LOWER ATTACHMENTS FOR PRIMARY AND SECONDARY LOAD PATH

NOTE: Two persons are necessary to do this procedure:

One person in the cockpit to operate the Trimmable Horizontal Stabilizer (THS) actuator, and
The other person to do the inspection of the THS actuator.

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	1	FLASHLIGHT
No specific	2	GAGE - FEELER
No specific	AR	MAT - PROTECTIVE
No specific	AR	WARNING NOTICE(S)
98D27403500000	1	PITCH TRIM CONTROL LOCKING

B. Consumable Materials

REFERENCE	DESIGNATION
(Material No.08BAA9)	Non Aqueous Cleaner-General - -
(Material No.14SBA1)	Textile-Lint free Cotton -

C. Work Zones and Access Panels

ZONE/ACCESS	ZONE DESCRIPTION
310	FUSLG TAIL SECTION AFT OF AFT PRESS BHD
312AR

D. Referenced Information

REFERENCE	DESIGNATION
TASK 12-22-27-640-003-A	Lubricate THS Actuator Ball Screw Nut
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 27-00-00-080-001-A	Removal of the Pitch-Trim Control Locking Tool (98D27403500000)
TASK 27-00-00-480-001-A	Installation of the Pitch-Trim Control Locking Tool (98D27403500000)
TASK 27-44-51-000-001-A	Removal of the Trimmable Horizontal Stabilizer (THS) Actuator
TASK 27-44-51-400-001-A	Installation of the Trimmable Horizontal Stabilizer (THS) Actuator
TASK 29-23-00-863-001-A	Pressurize the Green Hydraulic System from the Yellow Hydraulic System through the PTU with the Electric Pump
TASK 29-23-00-864-001-A	Depressurize the Green and Yellow Hydraulic Systems after Operation of the PTU
TASK 29-24-00-863-001-A	Pressurize the Yellow Hydraulic System with the Electric Pump
TASK 29-24-00-864-001-A	Depressurize the Yellow Hydraulic System
TASK 31-60-00-860-001-A	EIS Start Procedure
TASK 31-60-00-860-002-A	EIS Stop Procedure
NTM 519000
Clearances between the Secondary Nut Trunnion and the Junction Plate
Lower THS-Actuator Attachment

3. Job Set-up
Subtask 27-44-51-860-063-A

A. Aircraft Maintenance Configuration
(1) Energize the aircraft electrical circuits
(Ref. AMM TASK 24-41-00-861-002).
(2) Do the Electronic Instrument System (EIS) start procedure (Ref. AMM TASK 31-60-00-860-001).
(3) On the overhead panel, on FLT CTL panel 23VU, make sure that the ELAC 1 and SEC 1 pushbutton switches are pushed (the OFF and FAULT legends are off).
(4) On the overhead panel, on FLT CTL panel 24VU, make sure that the ELAC 2 and SEC 2 pushbutton switches are pushed (the OFF and FAULT legends are off).
(5) Pressurize the Green and Yellow hydraulic systems (Ref. AMM TASK 29-23-00-863-001) and (Ref. AMM TASK 29-24-00-863-001).
(6) In the cockpit, on the center pedestal:
(a) On the ECAM control panel, push the F/CTL pushbutton switch (on the lower ECAM Display Unit (DU), the F/CTL page comes into view).
(b) Turn the pitch trim control-wheels to the 13.5 deg (13.5 deg) UP position (mechanical stop).
(7) Depressurize the Green and Yellow hydraulic systems (Ref. AMM TASK 29-23-00-864-001) and (Ref. AMM TASK 29-24-00-864-001).

Subtask 27-44-51-941-080-A

B. Safety Precautions
(1) In the cockpit:
(a) Put the 98D27403500000 PITCH TRIM CONTROL LOCKING on the pitch trim control-wheel (Ref. AMM TASK 27-00-00-480-001).
(b) Put the WARNING NOTICE(S) in position to tell persons not to operate the pitch trim controls.
(2) Put the WARNING NOTICE(S) in position to tell persons not to pressurize the hydraulic systems:

In the cockpit, on the overhead panel, on the hydraulic section of HYD/FUEL panel 40VU, and
On the ground service panels of the Green, Yellow and Blue hydraulic systems.

Subtask 27-44-51-865-078-A

DELETED

Subtask 27-44-51-010-064-A

D. Get Access
(1) Put the ACCESS PLATFORM 3M (10 FT)- ADJUSTABLE in position below access door 312AR.
(2) Open access door 312AR.
(3) Put the MAT - PROTECTIVE in the area of the THS actuator to prevent damage to the structure.

4. Procedure
Subtask 27-44-51-220-058-A

A. General Visual Inspection of the Lower and Upper Clearances between the Secondary Nut Trunnion and the Junction Plate, on the Two Sides

Clearances between the Secondary Nut Trunnion and the Junction Plate

(1) Do a general visual inspection of the lower and upper clearances between the secondary nut trunnion and the junction plate, on the two sides NTM 519000.
(a) Use the GAGE - FEELER of 0.6 mm (0.0236 in.) thickness and the FLASHLIGHT to measure:

Clearance 'A' between the secondary nut trunnion and the bottom of the junction plate, and
Clearance 'A' between the secondary nut trunnion and the top of the junction plate.

1 Because of the slightly rounded profile of the secondary nut trunnion and the junction plate, do not use a feeler gauge that has a width of more than 10 mm (0.3937 in.).
2 Make sure that the feeler gauge of 0.6 mm (0.0236 in.) thickness moves freely between the mating faces.
a If the measured clearance 'A' is less than 0.6 mm (0.0236 in.):

Replace the THS actuator (Ref. AMM TASK 27-44-51-000-001) and (Ref. AMM TASK 27-44-51-400-001).
Do a general visual inspection of the lower and upper clearances between the secondary nut trunnion and the junction plate, on the two sides, refer to Para. 4.A.

b If the measured clearance 'A' is more than or equal to 0.6 mm (0.0236 in.):

Continue the procedure to do the detailed inspection of the lower THS-actuator attachment.

Subtask 27-44-51-220-068-A

B. Detailed Inspection of the Lower THS-Actuator Attachment

Lower THS-Actuator Attachment

(1) Clean these components and their adjacent area with the Non Aqueous Cleaner-General - - (Material No.08BAA9) and a Textile-Lint free Cotton - (Material No.14SBA1) :

The area around the secondary nut trunnion and the junction plate
The lower attachment of the THS actuator, and
The ball screw of the THS actuator.

(2) Use the MIRROR - INSPECTION, FLEXIBLE and the FLASHLIGHT to do a detailed inspection of the lower THS-actuator attachment.
(a) Make sure that the shafts, brackets, nuts, cotter pins, bolts, lugs, retainer washers and retainer nuts are correctly installed.
1 If one or more items are not installed correctly, contact Airbus for more instructions.
2 If all the items are correctly installed:

Continue the procedure to do a detailed inspection of the clearance between the THS actuator lug and the retainer washer.

Subtask 27-44-51-220-069-A

C. Detailed Inspection of the Clearance between the THS Actuator Lug and the Retainer Washer

Lower THS-Actuator Attachment

(1) Use the FLASHLIGHT to do a detailed inspection of the clearance between the THS actuator lug and the retainer washer on the two sides of the lower THS-actuator attachment.

CAUTION: MAKE SURE THAT THE SLIDING BUSHES, DISTANCE BUSHES AND SHOULDER BUSHES ARE CORRECTLY INSTALLED. IF THEY ARE NOT CORRECTLY INSTALLED, DAMAGE TO THE LOWER THSA ATTACHMENT CAN OCCUR.

(a) Make sure that the sliding bushes, distance bushes and shoulder bushes are correctly installed:
1 Use the GAGE - FEELER of 0.5 mm (0.0197 in.) thickness to measure clearance 'B' between the THS actuator lug and the retainer washer.
2 Make sure that the feeler gauge of 0.5 mm (0.0197 in.) thickness moves freely between the mating faces.
a If the measured clearance 'B' is less than 0.5 mm (0.0197 in.):

Replace the THS actuator (Ref. AMM TASK 27-44-51-000-001) and (Ref. AMM TASK 27-44-51-400-001).

b If the measured clearance 'B' is more than or equal to 0.5 mm (0.0197 in.):

Continue the procedure to do a detailed inspection of the THS actuator-ball screw.

Subtask 27-44-51-220-070-A

D. Detailed Inspection of the THS-Actuator Ball Screw

Lower THS-Actuator Attachment

(1) Use the MIRROR - INSPECTION, FLEXIBLE and the FLASHLIGHT to do a detailed inspection of the THS actuator ball screw.
Do a check for:

Dents
Cracks
Corrosion
Unsatisfactory surface protection.

(a) If you find damage on the ball screw thread, contact Airbus.
(b) If there is no damage on the ball screw thread, continue the procedure.
(2) Pressurize the Green and Yellow hydraulic systems (Ref. AMM TASK 29-23-00-863-001) and (Ref. AMM TASK 29-24-00-863-001).
(3) Remove the 98D27403500000 PITCH TRIM CONTROL LOCKING from the pitch trim control-wheel (Ref. AMM TASK 27-00-00-080-001).
(4) On the center pedestal, turn the pitch trim control-wheels to the neutral position.
(5) Put the 98D27403500000 PITCH TRIM CONTROL LOCKING on the pitch trim control-wheel (Ref. AMM TASK 27-00-00-480-001).
(6) Depressurize the Green and Yellow hydraulic systems (Ref. AMM TASK 29-23-00-864-001) and (Ref. AMM TASK 29-24-00-864-001).
(7) Use the FLASHLIGHT to do a detailed inspection of the part of the ball screw that was not in view.
Do a check for:

Dents
Cracks
Corrosion
Unsatisfactory surface protection.

(a) If you find damage on the ball screw thread, contact Airbus.
(b) If there is no damage on the ball screw thread, lubricate the THS-actuator ball screw nut (Ref. AMM TASK 12-22-27-640-003).

5. Close-up
Subtask 27-44-51-410-063-A

A. Close Access
(1) Make sure that the work area is clean and clear of tools and other items.
(2) Remove all the fixtures, tools, test and support equipment used during this procedure.
(3) Remove the MAT - PROTECTIVE.
(4) Close access door 312AR.
(5) Remove the access platform(s).

Subtask 27-44-51-865-086-A

DELETED

Subtask 27-44-51-860-083-A

C. Put the aircraft back to its initial configuration.
(1) Remove the WARNING NOTICE(S).
(2) Remove the 98D27403500000 PITCH TRIM CONTROL LOCKING from the pitch trim control-wheel (Ref. AMM TASK 27-00-00-080-001).
(3) Do the EIS stop procedure
(Ref. AMM TASK 31-60-00-860-002).
(4) De-energize the aircraft electrical circuits
(Ref. AMM TASK 24-41-00-862-002).

[Rev.10 from 2021] 2026.03.31 23:51:31 UTC