Aircraft Safety Wiring Basics | What Every A&P Needs to Know (How to lock wire)

Summary

This tutorial, presented by Northeast Aviation Pro, teaches the basics of safety wiring in aircraft maintenance. It covers the purpose and proper installation of lock wire to prevent fasteners from loosening due to vibrations. Key techniques include creating tight, consistent twists and ensuring the wire is correctly anchored to secure bolts, nuts, and other fasteners. The video also demonstrates safety precautions, such as using the right tools and avoiding over-twisting. The goal is to ensure fasteners remain tight and safe, even under challenging conditions.

Takeaways

• 😀 Safety wire prevents fasteners from loosening due to vibrations and forces.
• 😀 It's commonly used in aircraft and racing applications to secure screws, nuts, bolts, and other fasteners.
• 😀 Stainless steel wire (32 thou in diameter) is typically used for safety wiring in aircraft maintenance.
• 😀 Proper safety wire installation ensures fasteners are securely tightened and prevents them from moving.
• 😀 The wire should be twisted with 6 to 8 twists per inch for optimal security.
• 😀 Over-twisting the wire can weaken it, while under-twisting can make it ineffective.
• 😀 Use special twisting pliers to ensure the wire is twisted correctly and securely.
• 😀 Always ensure that the fastener being secured has been properly assembled and torqued before applying safety wire.
• 😀 A pigtail at the end of the wire is crucial to prevent sharp ends that could cause injury.
• 😀 Safety wire must not chafe or damage surrounding components, especially in sensitive areas like fuel tanks.
• 😀 The wire must be installed in the correct direction to ensure it tightens the fastener (righty tighty test).

Q & A

What is the purpose of safety wire in aviation and racing?

The purpose of safety wire, also known as lock wire, is to prevent fasteners from falling out due to vibrations and other forces. It also serves to indicate that the fastener has been properly tightened.

What materials are typically used for safety wire in aircraft applications?

In aircraft applications, stainless steel wire is commonly used, with a typical diameter of 32 thousandths (32 thou).

How is safety wire installed on fasteners?

Safety wire is threaded through a hole drilled into a fastener or part, then twisted and anchored to a second fastener or part. The twisting creates a pigtail, which ensures the wire stays secure and prevents fastener loosening.

How can you tell if safety wire has been installed correctly?

A correct installation can be confirmed by the 'righty tighty test.' If the wire causes the bolt to tighten when the fastener is rotated, the installation is correct.

What are the consequences of over-twisting safety wire?

Over-twisting safety wire can weaken it, making it more prone to breaking when subjected to additional stress.

What is the recommended twist rate for safety wire?

The recommended twist rate for safety wire is six to eight twists per inch to ensure it is tight and secure.

Why is it important to use twisting pliers when installing safety wire?

Twisting pliers are essential for properly gripping and twisting the safety wire. They ensure the wire is twisted tightly and evenly without causing excessive tension that could weaken it.

What precaution should be taken when installing safety wire in fuel tank areas?

When working in fuel tank areas, ensure the wire ends are bent along the wire and are kept close to the locked part. This prevents protrusions and potential hazards.

What should you do if there are excess lengths of safety wire after installation?

If there is excess wire, it should be cut off and discarded properly to prevent damage to the aircraft. The cut-off material should also be collected to avoid it causing any harm.

What are the different methods of safety wiring bolts demonstrated in the video?

The video demonstrates several methods of safety wiring bolts, including single twists for individual bolts, a crisscross pattern for two bolts, and a three-bolt wiring pattern. Each method ensures the fasteners stay secure under vibration.