DOC AIRBUS | AMM A320FBACKSHELL LOCKWIRE PROCEDURE - DESCRIPTION AND OPERATION
** ON A/C NOT FOR ALL
** ON A/C NOT FOR ALL
** ON A/C NOT FOR ALL
1. General
A. Procedure
(1) This section describes the standard practices for securing a connector, its backshell, and associate parts by the use of Lockwire.
(2) The lockwire is installed to prevent a part from becoming loose. The wire is installed to apply an opposing force so that a part will not disengage.
(3) The geneeral note section on the engineering drawing should specify the type and size of the safety wire to be used. If no instructions exist, use safety wire per MS20995N20.
2. Tools and Equipment
(See Table 1)
** ON A/C NOT FOR ALL (See Table 1)
| ------------------------------------------------ |
| ! REFERENCE ! DESIGNATION ! |
| !---------------------!------------------------! |
| ! No Specific ! Wire cutters ! |
| ! No Specific ! Pliers ! |
| ! No Specific ! Wire twisting pliers ! |
| ------------------------------------------------ |
| Tools and Equipment |
| Table 1 |
3. Consumable Material
(See Table 2)
** ON A/C NOT FOR ALL (See Table 2)
| ------------------------------------------------ |
| ! REFERENCE ! DESIGNATION ! |
| !---------------------!------------------------! |
| ! MS20995N20 ! Lockwire ! |
| ------------------------------------------------ |
| Consumable Material |
| Table 2 |
4. Reference Information
(See Table 3)
** ON A/C NOT FOR ALL (See Table 3)
| ------------------------------------------------ |
| ! REFERENCE ! DESIGNATION ! |
| !---------------------!------------------------! |
| ! 70-71-41 ! Connector backshell ! |
| ! ! replacement parts ! |
| ------------------------------------------------ |
| Reference Information |
| Table 3 |
5. Standard practices for Lockwire
A. Procedure
(1) There are three areas of the connector that need safety wiring:
(a) If a not-self-locking coupling nut is used, the coupling nut must be safety wired to a fixed point.
(b) If a backshell is used that provides a saddle clamp for strain relief, the saddle clamp mounting screws must be safety wired.
(c) If a backshell is installed that has safety wiring provisions in the coupling nut, it must be safety wired.
(2) Any non-self-locking coupling nuts used in high vibration areas must be safety wired. This includes the power plant area, and the pylon area.
Safety Wiring Connectors and Strain Relief ClampsNOTE: Safety wiring must installed in the direction that fastener or coupler tightening will be maintained.
(3) Where safety wiring is required on a series of two or more equipment mounting screws, the screws must be safety wired with one continuous length of wire.
(4) On strain relief saddle clamps, where a drilled head screw is not provided, replace the existing screw with a drilled fillister head screw of the same strength rating.
(5) All safety wiring is to be of the double twist wire method.
(6) safety wire must be installed so that if the item being safety wired becomes loose, it will apply a tightening pull on the attached point.
(7) Safety wiring twists must be uniform. There must be 6 to 10 twists per inch.
(8) Excess wire must be cut square and bent back.
6. Safety wiring procedure
| CAUTION: LOCKWIRE IS NOT REUSABLE: ALWAYS USE NEW LOCKWIRE. |
A. Procedure
- Safety wire the connector, adapter or backshell, as follows:
(1) Pull half the wire through the safety wire hole in the part being safety wired. Pull the right-hand wire end under the other wire end.
NOTE: When safety wire pliers are used, grip the wire near the end so that damaged wire will subsenquently be cut off.
(2) Twist the wires in a clockwise direction. Should the item being safety wired require counterclockwise tightening, the order of wire twisting would be reversed. Twist the wires tight enough to prevent loops. There shall be 6 to 10 twists per inch.
(3) Continue to twist the wires until they reach the attaching point sunch that if the item being safety wired tends to loosen, it will exert a tightening pull on the anchor. The twisted portion must be within 0.125 inch (93.18 mm) of attach point.
(4) Separate the wires and put one wire through the hole in the attach point.
(5) Join the wires again and twist the wires clockwise 0,25 to 0,50 inch (6.35 to 12.7mm) (two to five twists) beyond the attach point.
(6) Cut off the excess wire and bend the end back toward the attach point so that will not cause damage.