DOC AIRBUS | AMM A320FGeneral Instructions for the Uses of Lockwire [IAE]
TASK 70-40-11-911-012-A
General Instructions for the Uses of Lockwire
These instructions give the recommended procedure to safety different items in important areas.
The procedures only apply to those devices with a primary function to lock, but does not include devices which have lock properties as part of the items to be locked.
The procedures only apply to the types of lock devices specified in the sections that follow:
Lockwire - (Lockwire used to safety items).
2. Job Set-up Information
A. Work Zones and Access Panels
B. Referenced Information
3. Job Set-up
Subtask 70-40-11-869-053-A ** ON A/C NOT FOR ALL
Subtask 70-40-11-911-052-A ** ON A/C NOT FOR ALL
[Rev.10 from 2021]
2026.04.01 02:19:47 UTC
General Instructions for the Uses of Lockwire
ZONE: 400
1. Reason for the JobThese instructions give the recommended procedure to safety different items in important areas.
The procedures only apply to those devices with a primary function to lock, but does not include devices which have lock properties as part of the items to be locked.
The procedures only apply to the types of lock devices specified in the sections that follow:
Lockwire - (Lockwire used to safety items).
2. Job Set-up Information
A. Work Zones and Access Panels
| ZONE/ACCESS | ZONE DESCRIPTION |
|---|---|
| 400 | POWER PLANT, NACELLES AND PYLONS |
| REFERENCE | DESIGNATION |
|---|---|
| TASK 70-40-11-911-016-A | General Instructions for Uses of Safety Cable |
Lockwire and Lockwire Hole DataSubtask 70-40-11-869-053-A ** ON A/C NOT FOR ALL
A. General
(1) Safety cable is permitted at limited locations as an alternative to lockwire/safety. It is permitted to use safety cable per (Ref. AMM TASK 70-40-11-911-016) as an alternative to lockwire/safety wire as specified below.
(a) At all external and fan stream locations where the safety wire hole is sufficiently large for the cable, it is permitted to use only Safety Cable Part No AS3510-0218C ( 0.032 IN. (0.813 MM) diameter) and safety cable ferrule Part No AS3510-02F.
(b) Safety cable is not permitted at the subsequent locations:
1 Locations where the safety wire hole is more than 0.100 IN. (2.540 MM) diameter (the safety cable ferrule will pull through a hole larger than this)
2 Internal areas of the engine
3 Internal areas of gearboxes
4 Internal areas of accessories
5 Heat shields (as lacing)
6 Vendor-controlled (Category 1) components.
(2) If the Engine Manual specifies that it is permitted to use lockwire as an alternative to safety cable, use the applicable alternative:
(a) Where it is permitted to use lockwire as an alternative to 0.020 IN. (0.508 MM) diameter safety cable, the permitted lockwire is SAE Aerospace standard AS3214-01 lockwire.
(b) Where it is permitted to use lockwire as an alternative to 0.032 IN. (0.813 MM) diameter safety cable, the permitted lockwire is SAE Aerospace Standard AS3214-02 lockwire.
(c) Where it is permitted to use lockwire as an alternative to 0.040 IN. (1.016 MM) diameter safety cable, the permitted lockwire is SAE Aerospace Standard AS3214-03 lockwire.
4. Procedure(1) Safety cable is permitted at limited locations as an alternative to lockwire/safety. It is permitted to use safety cable per (Ref. AMM TASK 70-40-11-911-016) as an alternative to lockwire/safety wire as specified below.
(a) At all external and fan stream locations where the safety wire hole is sufficiently large for the cable, it is permitted to use only Safety Cable Part No AS3510-0218C ( 0.032 IN. (0.813 MM) diameter) and safety cable ferrule Part No AS3510-02F.
(b) Safety cable is not permitted at the subsequent locations:
1 Locations where the safety wire hole is more than 0.100 IN. (2.540 MM) diameter (the safety cable ferrule will pull through a hole larger than this)
2 Internal areas of the engine
3 Internal areas of gearboxes
4 Internal areas of accessories
5 Heat shields (as lacing)
6 Vendor-controlled (Category 1) components.
(2) If the Engine Manual specifies that it is permitted to use lockwire as an alternative to safety cable, use the applicable alternative:
(a) Where it is permitted to use lockwire as an alternative to 0.020 IN. (0.508 MM) diameter safety cable, the permitted lockwire is SAE Aerospace standard AS3214-01 lockwire.
(b) Where it is permitted to use lockwire as an alternative to 0.032 IN. (0.813 MM) diameter safety cable, the permitted lockwire is SAE Aerospace Standard AS3214-02 lockwire.
(c) Where it is permitted to use lockwire as an alternative to 0.040 IN. (1.016 MM) diameter safety cable, the permitted lockwire is SAE Aerospace Standard AS3214-03 lockwire.
Subtask 70-40-11-911-052-A ** ON A/C NOT FOR ALL
A. Instructions for the Uses of Lockwire.
(1) Lockwire is used to safety two or more items together. It must always be installed so that if the locked item tries to become loose, more tension will be applied to the lockwire.
(2) The usual procedure to install lockwire is to use a double length of wire, twisted together (Which is the double-twist procedure). Each twist is made when the wires are twisted through 180 degrees to make half a complete turn. A single-wire procedure can also be used when specified, where the items are close together and make a regular shape (That is a circle, rectangle, square or triangle). This procedure is also used for electrical system items and in locations where the single-wire procedure is recommended. At such times the single-wire procedure must only be used for items in regular shapes or for groups or parts that are almost the same.
(3) The maximum lockwire span between tension points is 6 in. (152.4 mm) unless specified differently.
(4) The maximum number of items that can be safetied together (By the double-twist or single-wire procedures), are those that can be locked by a 24 in. (0.6 m) length of lockwire.
(5) The lockwire must always be pulled tight when it is twisted. The number of twists to 1 in. (25.4 mm) is only a general guide.
(6) Always be careful when you twist the lockwire, to make sure that it is tight but not stressed too much. Light damage caused by the approved type of lockwire pliers can be accepted. Lockwire that is damaged because of incorrect tools or procedures can not be accepted. The surfaces of approved lockwire pliers, which hold the wire, must have rounded edges to prevent damage to the lockwire.
(7) The lockwire must be installed so that it can not become chafed, damaged by vibration or have too much tension applied. The tension must not be more than that which is necessary to keep the lockwire tight.
(8) The lockwire must always be attached to the holes supplied. Where there are no lockwire holes, the wire must be attached to an adjacent part; but always make sure that the part can operate correctly (Examples 13, 18 and 19).
(9) Always use new lockwire to safety the items.
(10) Hose and electrical coupling nuts must always be safetied the same as tube coupling nuts.
(11) Types of lockwire safety.
(Examples 1 to 28). Although not all of the possible types are shown, other procedures that are used must agree with these general instructions.
Subtask 70-40-11-911-053-A ** ON A/C NOT FOR ALL (1) Lockwire is used to safety two or more items together. It must always be installed so that if the locked item tries to become loose, more tension will be applied to the lockwire.
NOTE: For temperatures of up to 1200 deg.F (648.9 deg.C) , use a lockwire material of corrosion-resistant steel, such as AMS5689. For temperatures of up to 1800 deg.F (982.2 deg.C) use a lockwire material of heat and corrosion-resistant alloy, such as AMS5687. Where AMS or other material specifications are used, the diameter tolerances must be obeyed.
Do not use those given in the material specification. (2) The usual procedure to install lockwire is to use a double length of wire, twisted together (Which is the double-twist procedure). Each twist is made when the wires are twisted through 180 degrees to make half a complete turn. A single-wire procedure can also be used when specified, where the items are close together and make a regular shape (That is a circle, rectangle, square or triangle). This procedure is also used for electrical system items and in locations where the single-wire procedure is recommended. At such times the single-wire procedure must only be used for items in regular shapes or for groups or parts that are almost the same.
(3) The maximum lockwire span between tension points is 6 in. (152.4 mm) unless specified differently.
(4) The maximum number of items that can be safetied together (By the double-twist or single-wire procedures), are those that can be locked by a 24 in. (0.6 m) length of lockwire.
(5) The lockwire must always be pulled tight when it is twisted. The number of twists to 1 in. (25.4 mm) is only a general guide.
(6) Always be careful when you twist the lockwire, to make sure that it is tight but not stressed too much. Light damage caused by the approved type of lockwire pliers can be accepted. Lockwire that is damaged because of incorrect tools or procedures can not be accepted. The surfaces of approved lockwire pliers, which hold the wire, must have rounded edges to prevent damage to the lockwire.
(7) The lockwire must be installed so that it can not become chafed, damaged by vibration or have too much tension applied. The tension must not be more than that which is necessary to keep the lockwire tight.
(8) The lockwire must always be attached to the holes supplied. Where there are no lockwire holes, the wire must be attached to an adjacent part; but always make sure that the part can operate correctly (Examples 13, 18 and 19).
(9) Always use new lockwire to safety the items.
(10) Hose and electrical coupling nuts must always be safetied the same as tube coupling nuts.
(11) Types of lockwire safety.
(Examples 1 to 28). Although not all of the possible types are shown, other procedures that are used must agree with these general instructions.
B. Detail Instructions to Install Lockwire.
(1) Examine the items to be safetied, to make sure that they are correctly torqued. The specified torque limits must not be increased or decreased to align the lockwire holes. If it is not possible to align the holes with the correct torque applied, loosen the item and try again or use a different item.
(2) With adjacent items, the lockwire holes must point in approximately the same direction
(examples 1 to 4) for clockwise threads. Also, the lockwire must be installed so that the wire will try to pull the item in a clockwise direction. This procedure will be different for counterclockwise threads.
(3) Put the lockwire through the hole in the first item, then bend the wire around the head of that item. The direction in which the lockwire winds and twists, must be with the loop bent around the item so that the twisted wire can not move up to make a loose loop (Example 1).
(4) Hold the lockwires tight and twist until the twisted part almost touches the lockwire hole in the adjacent item. The twisted part must always be less than 0.125 in. (3.17 mm) from the lockwire holes in each item.
(5) Put the top wire through the lockwire hole in the second item, then bend the wire around the head of that item. The direction in which the lockwire winds and twists, must be with the loop bent around the item so that the twisted wire can not move up to make a loose loop, (Example 1 centre item).
If more than two items are to be safetied together, do this procedure again.
(6) When the last item is safetied, continue to twist the lockwire to make an end-piece. Use a minimum of four twists, to make sure that the end-piece can not become loose. Bend the end-piece to make sure that it can not become caught, then cut off all the unwanted lockwire. Always discard the unwanted lockwire, so that it can not cause damage.
the lockwire can go across the item (Example 12). For castellated nuts or taper head bolts, the lockwire can be bent across the item (Examples 5, 6 and 7).
Lockwire bent across the top of a bolt head (Example 3)
can also be accepted as an alternative to that bent around the bolt head.
(1) Examine the items to be safetied, to make sure that they are correctly torqued. The specified torque limits must not be increased or decreased to align the lockwire holes. If it is not possible to align the holes with the correct torque applied, loosen the item and try again or use a different item.
(2) With adjacent items, the lockwire holes must point in approximately the same direction
(examples 1 to 4) for clockwise threads. Also, the lockwire must be installed so that the wire will try to pull the item in a clockwise direction. This procedure will be different for counterclockwise threads.
(3) Put the lockwire through the hole in the first item, then bend the wire around the head of that item. The direction in which the lockwire winds and twists, must be with the loop bent around the item so that the twisted wire can not move up to make a loose loop (Example 1).
(4) Hold the lockwires tight and twist until the twisted part almost touches the lockwire hole in the adjacent item. The twisted part must always be less than 0.125 in. (3.17 mm) from the lockwire holes in each item.
(5) Put the top wire through the lockwire hole in the second item, then bend the wire around the head of that item. The direction in which the lockwire winds and twists, must be with the loop bent around the item so that the twisted wire can not move up to make a loose loop, (Example 1 centre item).
If more than two items are to be safetied together, do this procedure again.
(6) When the last item is safetied, continue to twist the lockwire to make an end-piece. Use a minimum of four twists, to make sure that the end-piece can not become loose. Bend the end-piece to make sure that it can not become caught, then cut off all the unwanted lockwire. Always discard the unwanted lockwire, so that it can not cause damage.
NOTE: Short end-pieces are recommended, because of vibration.
(7) As an alternative to the bent around lockwire (Example 1), the lockwire can go across the item (Example 12). For castellated nuts or taper head bolts, the lockwire can be bent across the item (Examples 5, 6 and 7).
Lockwire bent across the top of a bolt head (Example 3)
can also be accepted as an alternative to that bent around the bolt head.