Aircraft Mechanic how-to
How to Safety Wire a Pair of Bolts
Safety wiring keeps critical fasteners from backing off. Follow the maintenance manual and standard practices (such as FAA AC 43.13-1B).
Safety wiring keeps critical fasteners from backing off. Follow the maintenance manual and standard practices (such as FAA AC 43.13-1B). In short: torque; select; insert, then complete the remaining steps below.
Step by step
Torque the fasteners to specification first.
Select the correct wire diameter and material.
Insert wire through the first bolt hole so the pull will tighten the bolt.
Twist the wire to the specified number of twists per inch, keeping tension.
Insert one strand through the second bolt so it also pulls in the tightening direction.
Twist the pigtail three to six turns, cut it and bend it back to avoid snagging.
Inspect that the wire is tight, not nicked and correctly routed.
Safety reminders for aircraft mechanics
- Follow tool control and FOD prevention every shift
- Use fall protection on stands and aircraft surfaces
- Stay clear of engine intakes, exhausts and propellers
- Use respirators and gloves with fuel, solvents and composites
Key terms
A&P · Airworthiness · Airworthiness directive (AD) · Service bulletin · Annual inspection · 100-hour inspection: see the full aircraft mechanic glossary.