Aircraft Materials, Hardware & Processes
When lockwire (safety wire) is used to secure a fastener, how must the wire be routed relative to that fastener?
Answer
So any tension in the wire tends to tighten the fastener
Safety wire must always be installed so that the pull of the wire tends to tighten the fastener. If the fastener starts to back off, the wire goes into tension and resists further loosening. The double-twist method is standard and the wire is kept taut, not loose; routing it so it would loosen the fastener defeats the purpose of safetying.
Source: AC 43.13-1B, Ch. 7, Section 7 — Safetying (Safety Wire)
Not the answer
- As a single strand run loosely between fasteners
- So the wire carries no tension in either direction
- So any tension in the wire tends to loosen the fastener
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