DOC AIRBUS | AMM A320FMETAL OVERBRAID REPAIR PROCEDURE - DESCRIPTION AND OPERATION
** ON A/C NOT FOR ALL
** ON A/C NOT FOR ALL
** ON A/C NOT FOR ALL
1. General
** ON A/C NOT FOR ALL - When it is not possible to remove the damaged wire harness from the aircraft this procedure may be used to temporarily repair the metal overbraid, but only if the wires below the metal overbraid have not been damaged.
- The metal overbraid is installed on the harness to act as a shield for lightning strike protection. The wires below the metal overbraid are protected by an inner protective tape. Some harnesses have an outer jacket to protect the metal overbraid from wear and the harness from moisture contamination.
- This procedure was written as a temporary on-wing repair. A permanent repair must be incorporated at the next available time period and location, but not later than the next engine shop visit.
Engine Harness Assembly Layers2. Tools and Equipment
** ON A/C NOT FOR ALL | --------------------------------------------------------------------------- |
| ! REFERENCE ! DESIGNATION ! VENDOR ! |
| !------------------------------------------------------!------------------! |
| ! No specific ! Scissors ! Commercial ! |
| ! No specific ! Knife, utility ! Commercial ! |
| ! No specific ! Cutter, wire ! Commercial ! |
| -------------------------------------------------------------------------- |
3. Consumable Material
** ON A/C NOT FOR ALL | --------------------------------------------------------------------------- |
| ! REFERENCE ! DESIGNATION ! VENDOR ! |
| !-------------------------------------------------------------------------! |
| ! CP1041 ! Alcohol, isopropyl ! Commercial ! |
| ! HM352 ! Tape, insulating, high temperature ! V71643 ! |
| ! P423 ! Tape, insulating, high temperature ! V99742 ! |
| ! NSA8420-7 ! Tape, tying, fiberglass MIL-T-43435 Type4 ! V00768 ! |
| ! 23 X TZ ! Tape, tying, fiberglass MIL-T-43435 Type4 ! V82110 ! |
| ! 100-003A500 ! Tubular Metal Braiding ! V06324 ! |
| ! ! 0.500 in. (12.70 mm) Dia., ! (Glenair) ! |
| ! ! Nickel Plated Copper ! V31415 ! |
| ! ! ! (Santa Fe ! |
| ! ! ! Textiles) ! |
| --------------------------------------------------------------------------- |
4. Preparation for Harness Repair
A. Procedure
| WARNING: ISOPROPYL ALCOHOL IS FLAMMABLE AND THE VAPOR IS HARMFUL. USE |
| IN A WELL VENTILATED AREA. AVOID PROLONGED BREATHING OF VAPOR |
| AND REPEATED CONTACT WITH SKIN. OVER EXPOSURE MAY CAUSE HEADACHE, |
| DIZZINESS, AND DROWSINESS. PROTECTIVE GLOVES SHOULD BE WORN DURING |
| USE. MAY CAUSE DERMATITIS BY REMOVING SKIN OILS. |
(1) Clean the repair area with isopropyl alcohol.
(2) If installed, remove a piece of the harness outer jacket to access the damaged area.
(a) Measure an equal distance on each side of the damaged area and mark it.
(b) Use scissors or a utility knife to cut around the outer jacket at the marks. Do not damage the metal overbraid.
(c) Cut the outer jacket down the center from one mark to the other mark. Do not damage the metal overbraid.
(d) Remove the piece of the harness outer jacket.
(3) Remove the damaged piece of the metal overbraid.
(a) Measure an equal distance on each side of the damaged area and mark it.
(b) Use scissors or a wire cutter to cut around the metal overbraid at the marks. Do not damage the inner tape.
(c) Cut the metal overbraid down the center from one mark to the other mark. Do not damage the inner protective tape.
(d) Remove the damaged piece of the metal overbraid.
A. Procedure
(1) Cut a piece the metal overbraid to cover the repair area.
(a) The piece of overbraid should extend 1.5 in. (38.0999 mm) beyond the end of the repair area on each side.
(b) Cut the metal overbraid down the center and fold the edges under.
(c) Cut off any loose wires from the metal overbraid so that they will not go into the wire shield or the wire insulation.
(2) Wrap the piece of metal overbraid around the repair area.
(a) The piece of metal overbraid should be wrapped around the harness so that the end of the wrap overlaps the start.
(b) Tie the ends of the metal overbraid with tying tape.
1 Make two ties 0.5 in. (12.7000 mm) apart.
2 For the tie, use a clove hitch and a square knot.
(3) Do a continuity test on the repaired metal overbraid. Refer to 70-71-16. The overbraid must have continuity from end to end.
(4) Wrap the metal overbraid with two layers of insulating tape.
(a) Each wrap must overlap the last wrap by 50 percent.
(b) Wrap a second layer of insulating tape over the metal overbraid in the opposite direction of the first wrap.
(c) The wrap should extend 1 in. (25.4000 mm) and 1.5 in. (38.0999 mm) beyond the end of the repair area on the two sides.
(5) Tie the insulating tape with tying tape.
(a) The ties should be spaced 0.5 in. (12.7000 mm) apart.
(b) The ties should extend across the repair area.
(c) For the tie, use a clove hitch and a square knot.
6. Harness Outer Jacket Repair
A. Procedure
(1) If installed, repair the harness outer jacket, as follows.
(a) Tie the harness outer jacket at the open ends on each side of the repair area with tying tape.
(b) For the tie use a clove hitch and a square knot.
(c) Add at least two ties at each end.
(d) The ties should be spaced 0.5 in. (12.7000 mm) apart.