DOC AIRBUS | AMM A320FTemporary Repair of Hydraulic Tubes by Welding
TASK 20-23-11-300-008-A
Temporary Repair of Hydraulic Tubes by Welding
1. Reason for the Job
This procedure gives the procedure for the temporary repair of hydraulic tubes. This procedure uses manual T.I.G. welding.
A. Fixtures, Tools, Test and Support Equipment
B. Consumable Materials
C. Referenced Information
3. Job Set-up
Subtask 20-23-11-860-058-A
Subtask 20-23-11-917-086-A
[Rev.8 from Aug 2017]
2026.03.31 22:59:38 UTC
Temporary Repair of Hydraulic Tubes by Welding
1. Reason for the Job
This procedure gives the procedure for the temporary repair of hydraulic tubes. This procedure uses manual T.I.G. welding.
NOTE: This procedure is applicable to:
- Titanium-alloy (Ti-3Al-2.5V) tubes ref. ABS5004, sizes -04 to -16
- Corrosion-resistant steel (21.6.9) tubes ref. ASNA3288, sizes -04 to -24.
NOTE: It is not permitted to do a temporary repair on:
2. Job Set-up Information- Hydraulic tubes in the engine area
- Hydraulic tubes in the pylon forward secondary structure
- Hydraulic tubes in the fuel tanks
- Coiled tubes
- Hydraulic tubes installed on the landing gear legs.
A. Fixtures, Tools, Test and Support Equipment
| REFERENCE | QTY | DESIGNATION |
|---|---|---|
| No specific | AR | BRUSH - WIRE, STAINLESS STEEL |
| No specific | AR | CLOTH-EMERY (GRADE 400) |
| No specific | AR | CUTTER - MILLING, 2 CUT |
| No specific | AR | PAPER - ABRASIVE (GRADE 200) |
| REFERENCE | DESIGNATION |
|---|---|
| (Material No.08BAA9) | Non Aqueous Cleaner-General - - |
| REFERENCE | DESIGNATION |
|---|---|
| TASK 20-23-11-911-001-A | Installation of the Hydraulic Tubes |
| TASK 20-23-11-917-002-A | Installation and Repair of Hydraulic Lines |
Preparation of the Damage AreaSubtask 20-23-11-860-058-A
A. Procedure Requirements
(1) You must not do this repair on the aircraft. You must remove the pipe from the aircraft.
(2) Life limitation of the weld repair
(a) A temporary repair with this manual T.I.G. welding method is limited to a maximum of 20 Flight Cycles.
(a) The operators must have an approved licence/certificate (refer to the local Airworthiness Authorities) for:
(a) You can do this repair procedure only if:
(5) Adjustment of the welding parameters
(a) Before the repair, you must do a welding test on a specimen of tube of the same material and with the same diameter/thickness to get the applicable welding parameters (electrode diameter, amperage, power, etc).
(a) This repair method is applicable only for the tube materials that follow:
1 Titanium-Alloy (Ti-3Al-2.5V) Tubes
2 Corrosion-Resistant Steel (21.6.9) Tubes
(b) This repair method is not applicable for light alloy 6061T6 tube material.
4. Procedure(1) You must not do this repair on the aircraft. You must remove the pipe from the aircraft.
(2) Life limitation of the weld repair
(a) A temporary repair with this manual T.I.G. welding method is limited to a maximum of 20 Flight Cycles.
NOTE: You must replace the repaired tube by a new one before a maximum of 20 Flight Cycles.
(3) Certification of the operators (a) The operators must have an approved licence/certificate (refer to the local Airworthiness Authorities) for:
- Manual T.I.G. welding process,
- Dye penetrant test.
(a) You can do this repair procedure only if:
- The damage is a through crack with a maximum length of 10 mm (0.3937 in.).
- The distance between two cracks is not less than 15 mm (0.5906 in.).
- The weld does not change the geometry of the pipe.
- There is not already a repair in the repair area.
- Two longitudinal cracks are not on the same generatrix (line).
- The tube does not have more than 5% ovalization for stainless steel pipes and 3% for titanium pipes.
(5) Adjustment of the welding parameters
(a) Before the repair, you must do a welding test on a specimen of tube of the same material and with the same diameter/thickness to get the applicable welding parameters (electrode diameter, amperage, power, etc).
NOTE: You must do the steps described in this procedure during the welding test.
NOTE: You must identify the test specimens and keep them until the replacement of the repaired pipe.
(6) Weldable materials (a) This repair method is applicable only for the tube materials that follow:
1 Titanium-Alloy (Ti-3Al-2.5V) Tubes
| Tube Size | Tube DIA. in. | Tube DIA. mm | Thickness in. | Thickness mm | Operating Pressure psi (bar) |
|---|---|---|---|---|---|
| -04 | 1/4 | 6.35 | 0.016 | 0.406 | 3000 (206) |
| -06 | 3/8 | 9.525 | 0.019 | 0.483 | 3000 (206) |
| -08 | 1/2 | 12.70 | 0.026 | 0.66 | 3000 (206) |
| -10 | 5/8 | 15.875 | 0.032 | 0.813 | 3000 (206) |
| -12 | 3/4 | 19.050 | 0.039 | 0.991 | 3000 (206) |
| -16 | 1 | 25.4 | 0.051 | 1.295 | 3000 (206) |
| Tube Size | Tube DIA. in. | Tube DIA. mm | Thickness in. | Thickness mm | Operating Pressure psi (bar) |
|---|---|---|---|---|---|
| -04 | 1/4 | 6.35 | 0.016 | 0.406 | 3000 (206) |
| -06 | 3/8 | 9.525 | 0.019 | 0.508 | 3000 (206) |
| -08 | 1/2 | 12.70 | 0.026 | 0.66 | 3000 (206) |
| -10 | 5/8 | 15.875 | 0.032 | 0.838 | 3000 (206) |
| -12 | 3/4 | 19.050 | 0.051 | 0.991 | 3000 (206) |
| -16 | 1 | 25.4 | 0.052 | 1.321 | 3000 (206) |
| -24 | 1-1/2 | 38.1 | 0.024 | 0.609 | 80 (5.5) |
Subtask 20-23-11-917-086-A
A. Welding Procedure
(a) If the tube is painted (for stainless steel tubes):
1 Remove the paint with CLOTH-EMERY (GRADE 400) from the full circumference of the tube along a sufficient length around the damage area.
(b) Clean the outside of the tube with Non Aqueous Cleaner-General - - (Material No.08BAA9) .
(c) Flush the inside of the tube with Non Aqueous Cleaner-General - - (Material No.08BAA9) . Do the operation three or four times to remove all grease from the tube.
(d) Flush the tube with water.
(e) Let the tube dry in ambient air.
(2) Identify the location of the damage
(a) Blow dry compressed air, at a pressure of approximately 10 bar (145.0377 psi), through the tube.
(b) Soak the outer surface of the tube in water or apply a leak detection product to see the leak.
(c) Grind the surface of the tube along the full length of the crack to identify the damage area.
(d) Accurately identify each end of the crack. The identification mark must not be more than 2 mm (0.0787 in.) on each side of the length of the crack.
(3) Prepare the damage area for the repair
(a) With a CUTTER - MILLING, 2 CUT, make a groove along the length of the defect plus 5 mm (0.1969 in.) on either side of the crack.
2 The cutter must almost go through the tube wall (95% of the thickness).
(a) For stainless steel tubes:
1 Clean the area with a BRUSH - WIRE, STAINLESS STEEL.
1 Remove dust with Non Aqueous Cleaner-General - - (Material No.08BAA9) .
(a) Do the gaseous protection
(b) Weld the tube
1 Outside the tube:
(a) Do a visual inspection of the weld bead
1 Make sure that the width of the weld bead is:
If the maximum weld bead height is more than 0.1 mm (0.0039 in.):
1 Do a pressure test for 3 minutes minimum at ambient temperature with hydraulic fluid at:
1 Do a dye penetrant test in the welded area.
2 Make sure that there is no sign of a defect.
NOTE: You must remove the pipe from the aircraft to do this procedure.
(1) Clean the pipe (a) If the tube is painted (for stainless steel tubes):
1 Remove the paint with CLOTH-EMERY (GRADE 400) from the full circumference of the tube along a sufficient length around the damage area.
(b) Clean the outside of the tube with Non Aqueous Cleaner-General - - (Material No.08BAA9) .
(c) Flush the inside of the tube with Non Aqueous Cleaner-General - - (Material No.08BAA9) . Do the operation three or four times to remove all grease from the tube.
(d) Flush the tube with water.
(e) Let the tube dry in ambient air.
(2) Identify the location of the damage
(a) Blow dry compressed air, at a pressure of approximately 10 bar (145.0377 psi), through the tube.
(b) Soak the outer surface of the tube in water or apply a leak detection product to see the leak.
(c) Grind the surface of the tube along the full length of the crack to identify the damage area.
(d) Accurately identify each end of the crack. The identification mark must not be more than 2 mm (0.0787 in.) on each side of the length of the crack.
(3) Prepare the damage area for the repair
(a) With a CUTTER - MILLING, 2 CUT, make a groove along the length of the defect plus 5 mm (0.1969 in.) on either side of the crack.
NOTE: Use a 2-cut milling cutter with the characteristics:
1 The shape of the tool gives the width of the groove. - 40 teeth,
- Cut angle: 110 Deg.,
- DIA.: 15 mm (0.5906 in.),
- Width: 1.8 mm (0.0709 in.) or 2 mm (0.0787 in.) or 2.2 mm (0.0866 in.).
2 The cutter must almost go through the tube wall (95% of the thickness).
NOTE: If the cutter goes through the wall, the opening (at the inner surface) must not be more than 0.2 mm (0.0079 in.) on a length of a few millimeters.
(4) Clean the prepared area (a) For stainless steel tubes:
1 Clean the area with a BRUSH - WIRE, STAINLESS STEEL.
NOTE: Make sure that you use a clean stainless steel wire brush.
NOTE: Make sure that you do not cause damage to the pipe around the prepared area.
2 Remove dust with Non Aqueous Cleaner-General - - (Material No.08BAA9) . NOTE: Do not use a compressed air gun to remove dust.
(b) For titanium alloy tubes: 1 Remove dust with Non Aqueous Cleaner-General - - (Material No.08BAA9) .
NOTE: Do not use a compressed air gun to remove dust.
(5) Weld the tube (T. I. G. welding process) (a) Do the gaseous protection
NOTE: The welding torch gives protection to the outside of the tube.
1 Blow a neutral gas inside the tube with a flow rate of 4 to 10 l/min. for a sufficiently long time (about 10 min. for a long pipe). Decrease the flow rate to 4 l/min. during the welding operation. (b) Weld the tube
NOTE: Make sure that the welding equipment parameters are the same as those used on the test specimen.
1 For stainless steel 21-9-6 tubes: - Use Z2 CND 20-10-3 filler metal.
- Use T40 filler metal or AMS4951 standard filler metal.
1 Outside the tube:
- Continue the argon flow for at least one minute after welding.
- Continue to blow the inert gas through the tube for one minute after welding.
(a) Do a visual inspection of the weld bead
1 Make sure that the width of the weld bead is:
- 3 mm (0.1181 in.) for a tube thickness of less than 0.48 mm (0.0189 in.)
- Between 3 mm (0.1181 in.) and 5 mm (0.1969 in.) for a tube thickness of between 0.48 mm (0.0189 in.) and 1.3 mm (0.0512 in.).
If the maximum weld bead height is more than 0.1 mm (0.0039 in.):
- Grind and finish with PAPER - ABRASIVE (GRADE 200). Make sure that the remaining thickness is more than the thickness measured on the base metal.
NOTE: Light staining is permitted. On a small diameter tube, staining on the opposite side of the weld must remain within the limits of the thermally affected zone.
(b) Pressure test 1 Do a pressure test for 3 minutes minimum at ambient temperature with hydraulic fluid at:
- 360 bar (5221.3572 psi) for tube in stainless steel 21-9-6 - high pressure pipes
- 120 bar (1740.4524 psi) for tube in stainless steel 21-9-6 - low pressure pipes
- 15 bar (217.5566 psi) for tube in stainless steel 21-9-6 - suction pipes
- 360 bar (5221.3572 psi) for tube in titanium alloy TA3V2.5 - high pressure pipes
NOTE: No leak is permitted.
(c) Dye penetrant test 1 Do a dye penetrant test in the welded area.
2 Make sure that there is no sign of a defect.
NOTE: If you are not sure of the quality of the weld, rub with PAPER - ABRASIVE (GRADE 200) and do the dye penetrant test again.
3 If the dye penetrant test shows that there is a defect: - Discard the repaired pipe and install a new one on the aircraft (Ref. AMM TASK 20-23-11-911-001)
- Or remove the repaired part of the pipe. Cut the pipe at a minimum of 1.5 in. (38.0999 mm) from each end of the weld bead and do an approved repair (Ref. AMM TASK 20-23-11-917-002).
- Install the hydraulic tube (Ref. AMM TASK 20-23-11-911-001).