Check the Integrity of the THS Actuator Ball Screw Shaft (Primary and Secondary Load Path)

TASK 27-44-51-280-001-A
Check the Integrity of the THS Actuator Ball Screw Shaft (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.

NOTE: The configuration is aircraft on wheels. Do not use the rear safety stay for this integrity test.

ZONE: 310
FIN: 9CE

1. Reason for the Job
Refer to the MPD TASK: 274451-08
CHECK INTEGRITY OF THS ACTUATOR BALL SCREW SHAFT (PRIMARY AND SECONDARY LOAD PATH)
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	AR	WARNING NOTICE(S)
No specific	1	WRENCH - STANDARD
No specific	1	WRENCH - TORQUE
No specific	Torque wrench: range to between 6.0 and 5.0 m.daN (44.25 and 36.87 lbf.ft )
0U145409	1	SPECIAL WRENCH
0U190360	1	PIN-RIGGING,THS ACTUATOR,MECHANICAL INPUT LEVER
0U191191	1	CHECKING TOOL-BALL SCREW AND TIE BAR
98D27403003000	1	FIXTURE STRUT THSA
OR	OR
98D27403003001	1	FIXTURE STRUT THSA
98D27403500000	1	PITCH TRIM CONTROL LOCKING

B. Consumable Materials

REFERENCE	DESIGNATION
(Material No.06LCG9)	Non Hardening Jointing Putty-Medium Temp. Area - -
(Material No.08BBB1)	Non Aqueous Cleaner-- Petroleum Based -
(Material No.14QFB1)	Wire-Locking Dia: 0.8 mm CRES Nickel Alloy -

C. Work Zones and Access Panels

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

D. Expendable Parts

FIG.ITEM	DESIGNATION	IPC-CSN
35	TABWASHER	AIPC 27-44-51-06-050
35	TABWASHER	AIPC 27-44-51-06-055

E. Referenced Information

REFERENCE	DESIGNATION
TASK 12-22-27-640-003-A	Lubricate THS Actuator Ball Screw Nut
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 29-00-00-864-001-A	Put the Related Hydraulic System in the Depressurized Configuration before Maintenance Action
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 29-23-00-863-002-A	Pressurize the Yellow Hydraulic System from the Green Hydraulic System through the PTU with the Ground Service Cart
Location of the Rigging Pin for the THSA Mechanical Input Lever
Ball Screw Shaft - Integrity Check (Claw Stop without Brake Nut) (Part 1)
Ball Screw Shaft - Integrity Check (Part 2)
Ball Screw Shaft - Integrity Check (Claw Stop with Brake Nut) (Part 1)
Claw Stop with Brake Nut

3. Job Set-up
Subtask 27-44-51-010-056-A

A. Get Access
(1) Put the ACCESS PLATFORM 3M (10 FT)- ADJUSTABLE in position below access door 312AR.
(2) Open the access door 312AR.

Subtask 27-44-51-860-076-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) Pressurize the Green and the Yellow hydraulic system (Ref. AMM TASK 29-23-00-863-001) (Ref. AMM TASK 29-23-00-863-002).
(2) Turn the pitch-trim control wheel in the cockpit and put the THS actuator to the zero position.

Subtask 27-44-51-210-060-A

C. Inspection
(1) Make sure that the THSA will not move during this inspection.
(2) Clean the ball screw (23) with the Non Aqueous Cleaner-- Petroleum Based - (Material No.08BBB1) :
(3) Use a FLASHLIGHT and examine the ball screw (23) for:

Cracks
Corrosion
Satisfactory surface protection.

NOTE: If you find shiny marks on the ball screw (23), do not replace the THSA as these marks are permitted.
Refer to the Vendor SB for more data (Ref. SB 47145-27-10).

(4) Examine the area of the ball screw which you did not examine in step (2):
(a) Turn the pitch-trim control wheel in the cockpit and put the THS actuator until you can see the area which you could not see in step (2).
(b) Do steps (2) and (3) again for this area.
(5) After inspection of the ball screw (23) turn the pitch-trim control wheel in the cockpit and put the THS actuator to the zero position.
(6) Depressurize the Green and Yellow hydraulic system and put them in the maintenance configuration (Ref. AMM TASK 29-00-00-864-001).
(7) Put the 98D27403500000 PITCH TRIM CONTROL LOCKING on the pitch-trim control wheel in the cockpit.
(8) Put the WARNING NOTICE(S) in the cockpit to tell persons not to operate the pitch controls.
(9) Put the WARNING NOTICE(S) in position to tell persons not to pressurize the Green and Yellow hydraulic systems:

in the cockpit on the hydraulic section 40VU on the overhead panel,
on the ground service panels of the Green and Yellow hydraulic systems.

(10) Put the 0U190360 PIN-RIGGING,THS ACTUATOR,MECHANICAL INPUT LEVER in the mechanical input of the THS actuator.

Location of the Rigging Pin for the THSA Mechanical Input Lever

4. Procedure

NOTE: The complete integrity check has two parts. It is mandatory to do part 1 and part 2.

Subtask 27-44-51-280-052-A

A. Do an Integrity Check of the Ball Screw Shaft (Claw Stop without Brake Nut) (Part 1)

Ball Screw Shaft - Integrity Check (Claw Stop without Brake Nut) (Part 1)

(1) Installation of the Fixture Strut Tool 98D27403003000 FIXTURE STRUT THSA98D27403003001 FIXTURE STRUT THSA:
(a) Refer to the GSE Instruction Manual (GIM) to obey the detailed instructions.

NOTE: This AMM-task gives the information of the installation location of the tool parts. For the correct assembly of the tool it is necessary to use the GIM.

(b) Connect the hydraulic assy (1) with the correct extension (4).
(c) Put the end of the hydraulic assy (1) into the lower attach fitting (20) and install the quick release pin (3).
(d) Put the end of the extension (4) into the upper attach fitting (21) and install the quick release pin (3).

NOTE: You find the upper attach fitting (21) at the horizontal stabilizer (22).

(e) Connect the hydraulic hoses of the manual pump to the hydraulic connections (2) of the hydraulic assy (1).

NOTE: There are female and male couplings to make the connection clearly.

(2) Release the tabwasher (35) and remove the tie bar nut (36) with a 0U145409 SPECIAL WRENCH.
(3) Remove the tabwasher (35), the springwasher (34) from the fail safe tie-bar (33).
(4) Discard the tabwasher (35).
(5) Installation of the recording devices:

NOTE: Refer to the GSE Instruction Manual (GIM) to obey the detailed instructions.

(a) Install the ball screw comparator (6) to the ball screw (23).
(b) Before the installation of tie-bar comparator (5):

CAUTION: BEFORE YOU INSTALL/REMOVE THE GSE-TOOL, READ THE INSTRUCTIONS IN THE APPLICABLE GSE INSTRUCTION MANUAL. WHILE YOU OPERATE THIS TOOL, CAREFULLY OBEY THEM. IF YOU DO NOT OBEY THE INSTRUCTIONS, DAMAGE TO EQUIPMENT CAN OCCUR.

(c) Install the correct tie-bar comparator (5) to the fail safe tie-bar (33).
(d) Make sure that you do not compress the spring of the tie bar comparator (5) fully.
(6) At the manual pump: Make sure that valves 1 and 2 are open.
(a) For the 98D27403003001 FIXTURE STRUT THSA only:

Unlock the pump lever.
Open the relief purge.

(7) Put the selector of the manual pump to 'Compression'.
To get the necessary hydraulic pressure:

Press the pump lever slowly approximately one time each 5 seconds until the manometer shows 120 bar (1740 psi).
After that, press the pump lever each 10 seconds, until the manometer shows the pressure between 140 bar (2031 psi) to 150 bar (2176 psi):

(a) When the value of the pressure is reached, close valves 1 and 2.
(b) Adjust the two indicators to 0.
(8) Before you open the valves of the manual pump:
(a) Put the selector of the manual pump to 'Traction'.

CAUTION: OPEN THE VALVES OF THE MANUAL PUMP VERY CAREFULLY TO RELEASE THE PRESSURE SLOWLY. IF YOU DO NOT OBEY THIS INSTRUCTION, DAMAGE TO THE EQUIPMENT CAN OCCUR.

(b) Open the valves 1 and 2 very carefully.
To get the necessary hydraulic pressure:

Press the pump lever slowly approximately one time each 5 seconds until the manometer shows 380 bar (5511 psi).
After that, press the pump lever each 10 seconds, until the manometer shows the pressure between 420 bar (6092 psi) to 430 bar (6237 psi):

(c) When you get the correct value of the pressure, close valves 1 and 2.
(d) Read the value on the indicator of the tie bar comparator (5).
(e) Make sure that the value is not more than 0.100 mm (0.004 in.).
(f) If the value is more than 0.100 mm (0.004 in.), replace the THSA
(Ref. AMM TASK 27-44-51-000-001) and (Ref. AMM TASK 27-44-51-400-001).
(g) Read the value on the indicator of the ball screw comparator (6).
(h) Make sure that the value is not more than 0.750 mm (0.030 in.).
(i) If the value is more than 0.750 mm (0.030 in.), replace the THSA
(Ref. AMM TASK 27-44-51-000-001) and (Ref. AMM TASK 27-44-51-400-001).
(j) Before you open the valves of the manual pump:
1 Put the selector to 'Compression'.

CAUTION: OPEN THE VALVES OF THE MANUAL PUMP VERY CAREFULLY TO RELEASE THE PRESSURE SLOWLY. IF YOU DO NOT OBEY THIS INSTRUCTION, DAMAGE TO THE EQUIPMENT CAN OCCUR.

2 Open the valves 1 and 2 very carefully.

NOTE: You can release the pressure in the selector position from 'Traction' to 'Compression' or in the opposite direction.

(k) For the 98D27403003001 FIXTURE STRUT THSA only:

Close the relief purge.
Lock the pump lever.

(9) Remove the recording devices of the 98D27403003000 FIXTURE STRUT THSA98D27403003001 FIXTURE STRUT THSA:

Remove the tie bar comparator (5) from the fail safe tie-bar (33).
Remove the ball screw comparator (6) from the ball screw (23).

(10) Apply Non Hardening Jointing Putty-Medium Temp. Area - - (Material No.06LCG9) to the tie bar nut (36).
(11) Install the springwasher (34), the new AIPC 27-44-51-06-050 TABWASHER (35) and the tie bar nut (36) onto the fail safe tie-bar (33).

NOTE: The outer upper end of the springwasher (34) must have contact to the clawstop and the inner lower end to the tabwasher (35).

(12) Torque the tie bar nut (36) to between 6.0 and 5.0 m.daN (44.25 and 36.87 lbf.ft )

with the 0U145409 SPECIAL WRENCH.
(13) Safety the tie bar nut (36) with the new tabwasher (35).

Subtask 27-44-51-280-053-A

B. Do an Integrity Check of the Ball Screw Shaft (Claw Stop without Brake Nut) (Part 2)

Ball Screw Shaft - Integrity Check (Part 2)

WARNING: USE PROTECTIVE GOGGLES AND GLOVES WHEN YOU REMOVE OR INSTALL LOCKWIRE. EACH TIME YOU CUT LOCKWIRE, REMOVE AND DISCARD IT IMMEDIATELY. LOOSE LOCKWIRE CAN CUT YOU OR MAKE YOU BLIND, AND/OR CAN CAUSE DAMAGE.

(1) If necessary, remove and discard the lockwire from the screws. Do not loosen the screws.

NOTE: The removal of the lockwire can be necessary to get a better access to the machined area of the lower claw stop.

(2) Put the larger clamp of the 0U191191 CHECKING TOOL-BALL SCREW AND TIE BAR in position on the lower claw stop (with the graded scale in the up direction).
(3) Tighten the clamping nut.
(4) Put the smaller clamp of the 0U191191 CHECKING TOOL-BALL SCREW AND TIE BAR in position on the tie bar nut (36).
(5) Put the needle in the zero position of the graded scale and tighten the clamping nut.
(6) Put a WRENCH - TORQUE on the hexagonal end of the tie bar (secondary load path).
(7) Put a WRENCH - STANDARD on the machined area of the lower claw stop (primary load path).
(8) Hold the upper wrench in position and apply a TORQUE of 10 m.daN (73.75 lbf.ft) clockwise to the WRENCH - TORQUE.
(9) Look at the graded scale of the 0U191191 CHECKING TOOL-BALL SCREW AND TIE BAR.
(10) Make sure that the rotation is not more than 10 degrees.
(11) Do the above check procedure counterclockwise.
(12) If the rotation is more than 10 degrees, replace the THSA (Ref. AMM TASK 27-44-51-000-001) and (Ref. AMM TASK 27-44-51-400-001)
(13) Release the torque and remove the wrenches.
(14) Remove the 0U191191 CHECKING TOOL-BALL SCREW AND TIE BAR from the lower claw stop and the tie bar nut (36).
(15) If necessary, safety the screws with the lockwire 0.8 mm (0.0315 in.) 14QFB1Wire-Locking Dia: 0.8 mm CRES Nickel Alloy -.
(16) Remove the hydraulic assy (1) with the extension (4) and the manual pump, parts of the 98D27403003000 FIXTURE STRUT THSA98D27403003001 FIXTURE STRUT THSA.
(17) Remove the 0U190360 PIN-RIGGING,THS ACTUATOR,MECHANICAL INPUT LEVER from the mechanical input of the THSA.
(18) Lubricate the ball screw nut (Ref. AMM TASK 12-22-27-640-003).

Subtask 27-44-51-280-055-A

C. Do an Integrity Check of the Ball Screw Shaft (Claw Stop with Brake Nut) (Part 1)

Ball Screw Shaft - Integrity Check (Claw Stop with Brake Nut) (Part 1)

(1) Installation of the Fixture Strut Tool 98D27403003000 FIXTURE STRUT THSA98D27403003001 FIXTURE STRUT THSA:
(a) Refer to the GSE Instruction Manual (GIM) to obey the detailed instructions.

NOTE: This AMM-task gives the information of the installation location of the tool parts. For the correct assembly of the tool it is necessary to use the GIM.

NOTE: You find the upper attach fitting (21) at the horizontal stabilizer (22).

(e) Connect the hydraulic hoses of the manual pump to the hydraulic connections (2) of the hydraulic assy (1).

NOTE: There are female and male couplings to make the connection clearly.

(2) Release the tabwasher (35) and remove the tie bar nut (36).
(3) Remove the tabwasher (35), the brake nut (37), the springwasher (34) from the fail safe tie-bar (33).
(4) Discard the tabwasher (35).
(5) Installation of the recording devices:

NOTE: Refer to the GSE Instruction Manual (GIM) to obey the detailed instructions.

(a) Install the ball screw comparator (6) to the ball screw (23).
(b) Before the installation of tie-bar comparator (5):

Unlock the pump lever.
Open the relief purge.

(7) Put the selector of the manual pump to 'Compression'.
To get the necessary hydraulic pressure:

Press the pump lever slowly approximately one time each 5 seconds until the manometer shows 120 bar (1740 psi).
After that, press the pump lever each 10 seconds, until the manometer shows the pressure between 140 bar (2031 psi) to 150 bar (2176 psi):

(a) When the value of the pressure is reached, close valves 1 and 2.
(b) Adjust the two indicators to 0.

CAUTION: OPEN THE VALVES OF THE MANUAL PUMP VERY CAREFULLY TO RELEASE THE PRESSURE SLOWLY. IF YOU DO NOT OBEY THIS INSTRUCTION, DAMAGE TO THE EQUIPMENT CAN OCCUR.

(8) Before you open the valves of the manual pump:
Put the selector of the manual pump to 'Traction' and very carefully open the valves 1 and 2.

NOTE: Do not open the valves 1 and 2 at the same time, to switch from 'Compression' to 'Traction'. This will cause a sudden decrease of pressure.

(a) Open the valves 1 and 2 very carefully.
To get the necessary hydraulic pressure:

Press the pump lever slowly approximately one time each 5 seconds until the manometer shows 380 bar (5511 psi).
After that, press the pump lever each 10 seconds, until the manometer shows the pressure between 420 bar (6092 psi) to 430 bar (6237 psi):

(b) When you get the correct value of the pressure, close valves 1 and 2.
(c) Read the value on the indicator of the tie bar comparator (5).
(d) Make sure that the value is not more than 0.100 mm (0.004 in.).
(e) If the value is more than 0.100 mm (0.004 in.), replace the THSA
(Ref. AMM TASK 27-44-51-000-001) and (Ref. AMM TASK 27-44-51-400-001).
(f) Read the value on the indicator of the ball screw comparator (6).
(g) Make sure that the value is not more than 0.750 mm (0.030 in.).
(h) If the value is more than 0.750 mm (0.030 in.), replace the THSA
(Ref. AMM TASK 27-44-51-000-001) and (Ref. AMM TASK 27-44-51-400-001).

CAUTION: OPEN THE VALVES OF THE MANUAL PUMP VERY CAREFULLY TO RELEASE THE PRESSURE SLOWLY. IF YOU DO NOT OBEY THIS INSTRUCTION, DAMAGE TO THE EQUIPMENT CAN OCCUR.

(i) Before you open the valves of the manual pump:
Put the selector to 'Compression' and very carefully open the valves 1 and 2.

NOTE: You can release the pressure in the selector position from 'Traction' to 'Compression' or in the opposite direction.

(j) For the 98D27403003001 FIXTURE STRUT THSA only:

Close the relief purge.
Lock the pump lever.

(9) Remove the recording devices of the 98D27403003000 FIXTURE STRUT THSA98D27403003001 FIXTURE STRUT THSA:

Remove the tie bar comparator (5) from the fail safe tie-bar (33).
Remove the ball screw comparator (6) from the ball screw (23).

(10) Apply Non Hardening Jointing Putty-Medium Temp. Area - - (Material No.06LCG9) to the tie bar nut (36) and the thread of the fail safe tie-bar (33).
(11) Install the springwasher (34), the brake nut (37), the new AIPC 27-44-51-06-055 TABWASHER (35) and the tie bar nut (36) onto the fail safe tie-bar (33).

NOTE: The outer upper end of the springwasher (34) must have contact to the clawstop and the inner lower end to the brake nut (37).

(12) Tighten the tie bar nut (36) to get dimension A of 1.45 mm (0.057 in.) to 1.7 mm (0.067 in.) between the lower end of the claw stop (38) and the upper end of the brake nut (37).
(13) Safety the tie bar nut (36) with the new tabwasher (35).

Subtask 27-44-51-280-054-A

D. Do an Integrity Check of the Ball Screw Shaft (Claw Stop with Brake Nut) (Part 2)

Ball Screw Shaft - Integrity Check (Part 2)

Claw Stop with Brake Nut

(1) If necessary, remove and discard the lockwire from the screws. Do not loosen the screws.

NOTE: The removal of the lockwire can be necessary to get a better access to the machined area of the lower claw stop.

(2) Put the larger clamp of the 0U191191 CHECKING TOOL-BALL SCREW AND TIE BAR in position on the lower claw stop (with the graded scale in the up direction).
(3) Tighten the clamping nut.
(4) Put the smaller clamp of the 0U191191 CHECKING TOOL-BALL SCREW AND TIE BAR in position on the tie bar nut (36).
(5) Put the needle in the zero position of the graded scale and tighten the clamping nut.
(6) Put a WRENCH - TORQUE on the hexagonal end of the tie bar (secondary load path).
(7) Put a WRENCH - STANDARD on the machined area of the lower claw stop (primary load path).
(8) Hold the upper wrench in position and apply a TORQUE of 10 m.daN (73.75 lbf.ft) clockwise to the WRENCH - TORQUE.
(9) Look at the graded scale of the 0U191191 CHECKING TOOL-BALL SCREW AND TIE BAR.
(10) Make sure that the rotation is not more than 10°.
(11) Do the above check procedure counterclockwise.
(12) If the rotation is more than 10°, replace the THSA (Ref. AMM TASK 27-44-51-000-001) and (Ref. AMM TASK 27-44-51-400-001)
(13) Release the torque and remove the wrenches.
(14) Remove the 0U191191 CHECKING TOOL-BALL SCREW AND TIE BAR from the lower claw stop and the tie bar nut (36).
(15) If necessary, safety the screws with the lockwire 0.8 mm (0.0315 in.) 14QFB1Wire-Locking Dia: 0.8 mm CRES Nickel Alloy -.
(16) Remove the hydraulic assy (1) with the extension (4) the manual pump, parts of the 98D27403003000 FIXTURE STRUT THSA98D27403003001 FIXTURE STRUT THSA.
(17) Remove the 0U190360 PIN-RIGGING,THS ACTUATOR,MECHANICAL INPUT LEVER from the mechanical input of the THSA.
(18) Lubricate the ball screw nut (Ref. AMM TASK 12-22-27-640-003).

5. Close-up
Subtask 27-44-51-410-056-A

A. Close Access
(1) Make sure that the work area is clean and clear of tools and other items.
(2) Close the access door 312AR.
(3) Remove the WARNING NOTICE(S).
(4) Remove the access platform(s).

[Rev.10 from 2021] 2026.03.31 23:51:36 UTC