DOC AIRBUS | AMM A320FBACKSHELL LOCKWIRE PROCEDURE - DESCRIPTION AND OPERATION
** ON A/C NOT FOR ALL
** ON A/C NOT FOR ALL
1. General
** ON A/C NOT FOR ALL - This chapter gives the procedure to lockwire the coupling nut, shell, and the strain relief clamp and coupling nut which are the detail parts of the backshell assembly.
- Consumable materials can be replaced with equivalent items.
2. Standard equipment
** ON A/C NOT FOR ALL - None
3. Consumable material
** ON A/C NOT FOR ALL | ------------------------------------------------------------------------------- |
| ! REFERENCE ! DESIGNATION ! |
| ------------------------------------------------------------------------------- |
| ! V02-127 ! Lockwire (MS9226-03) ! |
| ! V02-138 ! Lockwire (AS44725-01) ! |
| ! V02-141 ! Lockwire (AS3214-02) ! |
| ! V02-146 ! Lockwire (MS20995-C20) ! |
| ! V02-176 ! Lockwire (MS20995-N20) ! |
| !-----------------------------------------------------------------------------! |
4. Standard Practices for Lockwires
A. Procedure
(1) Lockwire is used to safety two or more parts together. It must also be installed so that if the locked part tries to come loose, more tension will be applied to the lockwire.
(2) Use a lockwire material of corrosion-resistant steel such as AMS 5689 for temperatures of up to 649 deg.C (1200 deg. F) as found in the consumable materials.
(3) A maximum of three parts can be lockwired with the same wire.
(4) The maximum lockwire span between holes is 75 mm (2.95 in.).
(5) It is not necessary to twist the wire if the distance between the two holes is 5 mm (0.19 in.) or less.
(6) When you safety the last part, continue to twist the lockwire to make an end-piece 20 mm (0.78 in.) in length. Bend the end-piece to make sure that it cannot become caught, then cut-off all the unwanted lockwire. Always discard the unwanted lockwire, so that it cannot cause damage.
(7) Use the applicable size lockwire to the correct hole size and the correct number of twist to the inch (25,4 mm).
| ------------------------------------------------------------------------------- |
| ! Lockwire ! Wire Diameter ! Twist to ! Recommended ! |
| ! Number ! Inch (mm) ! the Inch ! Hole Diameter ! |
| ! ! ! (25,4 mm) ! Inch (mm) ! |
| ------------------------------------------------------------------------------- |
| ! V02-138 ! 0.019 - 0.021 ! 9 - 12 ! 0.037 - 0.057 ! |
| ! (AS44725-01) ! (0,483 - 0,533) ! ! (0,094 - 1,44) ! |
| ! ! ! ! ! |
| ! V02-127 ! 0.024 - 0.026 ! 9 - 12 ! 0.060 - 0.080 ! |
| ! (MS9226-03) ! (0,610 - 0,660) ! ! (1,53 - 2,03) ! |
| ! ! ! ! ! |
| ! V02-141 ! 0.030 - 0.034 ! 7 - 10 ! 0.060 - 0.080 ! |
| ! (AS3214-02) ! (0,770 - 0,860) ! ! (1,53 - 2,03) ! |
| ! ! ! ! ! |
| ! V02-146 ! 0.019 - 0.021 ! 9 - 12 ! 0.037 - 0.057 ! |
| ! (MS20995-C20)! (0,483 - 0,533) ! ! (0,094 - 1,44) ! |
| ! ! ! ! ! |
| ! V02 - 176 ! 0.029 - 0.021 ! 9 - 12 ! 0.037 - 0.057 ! |
| ! (MS20995-N20)! (0,483 - 0,533) ! ! (0,094 - 1,44) ! |
| !-----------------------------------------------------------------------------! |
5. Backshell Lockwire Procedures
Safety the backshell detail parts with lockwire by one of the procedures that follows. Refer to step (1) or step (2) for the applicable backshell type.
Safety the backshell detail parts with lockwire by one of the procedures that follows. Refer to step (1) or step (2) for the applicable backshell type.
A. Procedure
(1) Safety the backshell with lockwire as follows:
Backshell Lockwiring(a) Cut a piece of new lockwire to safety the coupling nut and shell and the strain relief clamp and coupling nut screw.
(b) Put the wire through the hole in the shell and coupling nut.
(c) Twist the wire. Do not pull the wire too much.
(d) Separate the twisted wire at the shell's center hole.
(e) Put one of the wires through the center hole in a direction that tightens and twist the wire.
(f) Separate the twisted wire at one of the two screws on the strain relief clamp and coupling nut.
(g) Put one of the wires through the screw hole in a direction that tightens and twist the wire to make a wire end-pièce.
(i) Cut and discard the unwanted end-piece.
(j) Cut a piece of new lockwire to safety the shell center hole to the screw on the strain relief clamp and coupling nut.
(k) Put the wire through the center hole in the shell.
(l) Twist the wire. Do not pull the wire too much.
(m) Separate the twisted wire at the screw hole on the strain relief clamp and coupling nut.
(n) Put one of the wires through the screw hole in a direction that tightens and twist the wire to make a wire end-piece.
(o) Bend the end-piece around the screw.
(p) Cut and discard the unwanted end-piece.
(2) Safety the backshell with lockwire as follows.
(a) Cut a piece of new lockwire to safety the coupling nut to the shell.
(b) Put the wire through the hole in the coupling nut.
(c) Twist the wire. Do not pull the wire too much.
(d) Separate the twisted wire at the shell hole.
(e) Put one of the wires through the shell hole in a direction that tightens and twist the wire to make an end-piece.
(f) Bend the end-piece toward the shell.
(g) Cut and discard the unwanted end-piece.
(h) Cut a piece of new lockwire to safety the shell to the strain relief clamp and coupling nut flange hole.
(i) Put the wire through the same hole in the shell that you safetied before.
(j) Twist the wire. Do not pull the wire too much.
(k) Separate the twisted wire at one of the two holes in the strain relief clamp and coupling nut flange hole.
(l) Put one of the wire through the hole in a direction that tightens and twist the wire to make an end-piece.
(m) Bend the end-piece toward the clamp.
(n) Cut and discard the unwanted end-piece.
(o) Cut a piece of new lockwire long enough to safety the screw to the strain relief clamp and coupling nut flange hole.
(p) Put the wire through the hole in one of the two screws in a direction that tightens.
(q) Twist the wire. Do not pull the wire too much.
(r) Separate the twisted wire at the hole in the strain relief clamp and coupling nut flange.
(s) Put the wire through the hole in the clamp flange in a direction that tightens and twist the wire to make a wire end-piece.
(t) Bend the end-piece toward the clamp flange.
(u) Cut and discard the unwanted end-piece.
(v) Do steps (0) thru (u) for the screw that remains in the strain relief clamp and coupling nut.