In-Depth Look at Military Standard Safety Wire: Specs, Features, and Benefits
Apr 2nd 2025
Safety wire, also known as lock wire or locking wire, is used on an aircraft to prevent vibrational loosening, enhance structural integrity and prevent tampering. Required in some applications by aircraft safety wire standards set by Federal Aviation Administration (FAA) standards, aircraft safety wire provides an additional level of security and protection if a fastener or locking mechanism fails. Military Standard aviation safety wire comes in various diameters and strengths, each offering different features and benefits that can be beneficial to a specific application. Whether you're learning how to safety wire for the first time or brushing up on safety wire how-to techniques, it's a key skill in maintenance.
Safety wire is lightweight and easy to use, making it the ideal choice for securing fasteners and ensuring the integrity of critical systems. Safety wire comes in a variety of sizes to match the type of fastener you are trying to secure. The wire is lightweight and flexible, yet strong enough to keep everything together.
Mil-Spec Standards
When shopping for aircraft safety wire, you'll notice that mil-spec standards are usually used to classify different types of safety wire. While there are many standards, a few stand out in aircraft safety wiring and safety wiring applications:
- M22759 (SAE AS22759)- This type of safety wire is designed for use in extreme conditions, like engine controls and critical electronics systems needed to fly in severe weather. Mil-spec M22759 safety wire is also suitable for use in areas where exposure to moisture is likely.
- M16878 - For extreme temperatures and voltage ratings, mil-spec M16878 safety wire is the go-to choice. This type of safety wire is usually made from materials like PVC, PTFE, polyalkene-PVC and ETFE. Mil-spec M16878 safety wire can be used for appliance wiring, power supplies and other electronic systems routinely exposed to high temperatures.
- M25038 - Designed to resist vibration and flame exposure, a go-to for airplane safety wire use. Mil-spec M25038 safety wire is designed to resist vibration and direct flame exposure, making it an ideal choice for use in your aircraft's critical systems, including circuitry.
- M13486 - For low-tension applications, mil-spec M13486 safety wire is a great choice. The wire is available in different slants to suit various applications and is also resistant to moisture and abrasion. M13486 safety wire is designed to remain flexible, even at low temperatures.
- M5086 - Mil-spec M5086 safety wire is ideal for general-purpose applications across a range of industries. It includes a tin-plated copper conductor insulated by PVC and a nylon jacket. It is ideal for applications where abrasion, impact, cutting or exposure to chemicals is likely.
Safety Wire Features
From 032 safety wire to ultra-flexible options, safety wiring offers plenty of unique features that make it a valuable tool in various applications that require a little extra stability and security. While not all safety wire is created the same, some primary features are fairly universal no matter which type or size of safety wire you choose. All safety wire delivers a strong hold and is flexible enough to be wrapped around a fastener or other component. Safety wire pliers are often used to install the wire with less hand fatigue.
- Strong Hold: No matter which type of safety wire you choose, you can expect it to have a strong hold. The primary function of safety wire is to secure components, preventing nuts, bolts, screws and other types of fasteners from coming loose due to vibration, temperature fluctuations or other hazards of flight. This feature is critical and universal.
- Locking Mechanism: Safety wire is designed to lock in place, keeping components secure flight after flight. How you install the safety wire can impact how well it locks. Pigtail twisting is a common method of installing safety wire and can be done using safety wire pliers.
- Flexible and Pliable: Safety wire is made to be flexible enough to wrap around components and fasteners. It is also pliable, allowing it to conform to the shape of the fastener it is securing. Flexibility and pliability are key features to look for when choosing safety wire.
- Corrosion Resistant: Most safety wire is corrosion resistant because it will come in contact with moisture at some point. Being resistant to environmental hazards is critical to maintaining strength and a solid hold.
- High Tensile Strength: A high tensile strength means the safety wire can withstand heavy loads before breaking. This is especially important in high-stress environments.
- Color-coded: Some safety wires are color-coded so it's easy to distinguish. The color coding may indicate the wire diameter or how the safety wire is being used.
- Versatile: All safety wire is versatile and can be used wherever you need extra strength and stability. Use safety wire in a variety of applications throughout your aircraft to make sure fasteners are secure, components are in place and nothing has been tampered with. Enjoy versatility across all aircraft safety wiring tasks.
Safety Wire Benefits
There are many benefits to using safety wire on your aircraft. When used correctly, safety wire can help reduce repairs and in-air emergencies, improving safety overall without adding a lot to your operational budget. The right safety wire is a key component in any toolbox, offering security and allowing for quick in-flight repairs.
Not all safety wire is the same, so benefits may vary from one type of wire to another. However, the basic benefits are similar no matter which type of safety wire you buy. Some of the benefits of safety wire include:
- Prevents Loosening: Safety wire is most often used to keep fasteners secure. When used properly, safety wire can prevent fasteners from backing out or loosening, keeping all the connections on your aircraft tight and ready for flight.
- Fewer Repairs: A lost nut or screw can spell disaster in the sky, grounding your aircraft and throwing off your schedule. Fewer repairs mean less downtime and less revenue loss. A simple length of safety wire can prevent many small repairs and keep your aircraft in the sky - where it belongs.
- Inexpensive: Safety wire is one of the cheapest and easiest preventative measures you can take when it comes to keeping your aircraft flight-ready. Safety wire is typically sold by the roll and is relatively cheap compared to other maintenance tools and consumables. Even safety wire pliers and other tools are relatively cheap compared to other items.
- Streamlines Inspections: Properly installed safety wire can streamline the inspection process, saving time and improving safety. Properly installed safety wire provides a visual indicator that a component is secure and has been meticulously installed. Maintenance personnel can easily identify any components needing repair by simply checking to see if the wire has been disturbed.
Conclusion
Military Standard safety wire offers a durable, reliable and inexpensive solution to preventing vibrational forces, temperature changes and other common flight hazards from grounding your aircraft. Whether you're performing routine maintenance or prepping for a long haul, safety wire is an essential part of your toolkit. Safety wire is used to keep fasteners in place, to secure components and, in some cases, to guard against tampering or accidental loosening caused by in-flight stress. Safety wire is a simple, yet effective way to enhance overall safety and ensure your aircraft always stays airworthy. Safety wire comes in various diameters and is typically sold by the roll for the best value possible. Make sure your aircraft is ready for flight by securing fasteners and other critical components with high-quality Military Standard safety wire from SkyGeek.
Whether you're securing fasteners or brushing up on how to safety wire, aircraft safety wire and mousing wire are essential tools in your aviation toolkit. Stay flight-ready and know that SkyGeek's got your back with quality aviation safety wire.