Repair of an Elbow Figure 246/TASK 20-23-11-991-039
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Initial Torque for the Nuts Figure 247/TASK 20-23-11-991-033
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(6) Do a check of the tube joint.
R R (a) Loosen the nut and examine the swaging of the sleeve: - there must be a small bulge between the cutting edge and the mating shoulder of the nut, - the surface of the sleeve must be smooth (there must be no cracks or surface defects), - the end of the sleeve must not be flat (the nut must move freely along the sleeve).
(b) Install the lines. Use the specified torque values (refer to the table). (Ref. Fig. 248/TASK 20-23-11-991-034)
NOTE : You must use these torque values each time that you____ assemble the tubes.
Subtask 20-23-11-917-064
B. Temporary Tube Repair with Flexible Hoses
(1) Installation conditions
R R R (a) One temporary repair with a flexible hose is permitted for each hydraulic system (Green, Yellow or Blue) if there is not more than one other temporary repair on the system.
R R (b) A temporary repair with a flexible hose is permitted on two systems if there is no temporary repair on the third system.
R R R R R (c) A temporary repair with two or more flexible hoses end-to-end is permitted if: - the repair is on one pipe only (between two pipe unions), - unions are installed between the flexible hoses.
R (2) Operation conditions
R R R (a) It is mandatory to: - replace the temporary repair (flexible hose) by a permanent repair at 20 takeoffs or the next A-check,
R R NOTE : You must replace the temporary repair by a permanent____ repair before the limit that occurs first.
R R - do an inspection of the repair each day to make sure that it is in the correct condition.
Torque Values Figure 248/TASK 20-23-11-991-034
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R (b) If possible, attach the flexible hose to an adjacent pipe or other hose with ty-wraps and spacers (Ref. TASK 20-23-14-910-001) to prevent chafing with the adjacent structure. If there is a risk of chafing between the hose and the structure/component, install a chafe guard on related part of the hose.
R (3) The flexible hose that you use must: - at minimum, be specified for use with the operation pressure in the system, - be specified for use with the type of fluid used in the system, - have, at minimum, the same inner diameter as the damaged tube, - have sufficient length to replace the damaged tube or the damaged part of the tube.
(4) Obey these installation rules: (Ref. Fig. 249/TASK 20-23-11-991-041, 250/TASK 20-23-11-991-042)
R R (a) The flexible hose must have an overlength or a curve because of changes in length caused by pressure. The hose length changes: - from +2 to -2.9% for a moderate pressure, - from +2 to -2% for a high pressure.
R R (b) There must be no flexure at the fittings. The hose must be straight for a minimum of two hose diameters from the fitting.
(c) Obey the min. bend radius of the hose (Ref. Fig. 251/TASK 20-23-11-991-035) To prevent sharp bends in the hose assembly, use: - elbow fittings, - hose with elbow-type end fittings.
(d) When you install the hoses, you must not twist them. This can cause the hose to break or the attachment nuts to become loose.
R The use of swivel connections at one end or at the two ends will
R prevent distortion stresses.
(e) In all operation conditions, there must be clearance between the hose assemblies and:
- the other lines, - the adjacent structure, - the equipment. Hose minimum clearances must be as follows:
Temporary Hydraulic Tubing - Repair Figure 249/TASK 20-23-11-991-041
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Temporary Hydraulic Tubing - Repair Figure 250/TASK 20-23-11-991-042
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Minimum Bend Radius for Hydraulic Hoses Figure 251/TASK 20-23-11-991-035- 12 (SHEET 1)
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Minimum Bend Radius for Hydraulic Hoses Figure 251/TASK 20-23-11-991-035- 22 (SHEET 2)
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------------------------------------------------------------------------------| HOSE CLEARANCE TO | MINIMUM CLEARANCE (INCH) | ------------------------------------------------------------------------------| CONTROL CABLES AND LINKAGES | 1.0 | |---------------------------------------|------------------------------------| | CABLE AT PULLEYS | 0.5 | |---------------------------------------|------------------------------------| | CABLE AT MIDDLE OF SPAN | 2.0 | |---------------------------------------|------------------------------------| | ELECTRICAL WIRING | 0.5 | |---------------------------------------|------------------------------------| | HYDRAULIC TUBES OR HOSES | 0.2 | ------------------------------------------------------------------------------ 中國航空網 www.k6050.com 航空翻譯 www.aviation.cn 本文鏈接地址：A320飛機維護手冊 AMM STANDARD PRACTICES-AIRFRAME(39)
