When it comes to aircraft maintenance, repair, and construction, every component matters. While avionics, engines, and instruments often receive the spotlight, the humble AN bolt, nut, and washer play a critical role in keeping aircraft airworthy and safe.At Comet Aviation Supplies, we stock a comprehensive range of AN Hardware designed to meet the demanding requirements of aviation applications. Whether you’re maintaining a certified aircraft, working on a homebuilt project, or servicing a ROTAX-powered aircraft, using the correct aviation-grade hardware is essential.
What Does AN Mean?
AN stands for Aircraft-Navy, a military specification system developed jointly by the United States Army Air Forces and the U.S. Navy. The standard was created to ensure consistency, reliability, and interchangeability of aircraft hardware across different aircraft manufacturers and maintenance organizations.Today, AN hardware remains widely used throughout the aviation industry because of its proven quality, standardized dimensions, and dependable performance.Why Aviation Hardware Is Different
A common misconception is that any bolt or nut of the correct size can be used in an aircraft. In reality, aviation hardware is specifically engineered to operate in demanding environments where vibration, temperature changes, and repeated loading cycles are routine.AN hardware provides:- High-strength materials
- Precise manufacturing tolerances
- Corrosion-resistant finishes
- Consistent traceability and quality standards
- Predictable performance under aviation loads
Understanding AN Bolts
AN bolts are among the most commonly used fasteners in aviation.Unlike standard hardware-store bolts, AN bolts feature:Precision-Shanked Design
The smooth shank carries the load while minimizing wear in the hole. Threads should generally not be positioned in the load-bearing area of the joint.Corrosion Protection
Most AN bolts feature cadmium or equivalent protective plating to resist corrosion in challenging operating environments.Standardized Sizing
AN bolt sizing follows a predictable format, making identification easier and ensuring compatibility throughout the aircraft.Example: AN4-20A- AN = Aircraft-Navy standard
- 4 = 1/4-inch diameter
- 20 = Length designation
- A = Undrilled shank
The Role of AN Nuts and Washers
Aviation fastening systems are designed as complete assemblies.AN Nuts
Depending on the application, various nut types are used:- Elastic stop nuts (Nyloc)
- Castellated nuts
- Shear nuts
- Self-locking nuts
AN Washers
AN washers distribute loads evenly and help protect mating surfaces from damage. They are also frequently used to achieve proper fitment, spacing, and alignment during assembly.Selecting the correct washer thickness and configuration is just as important as choosing the correct bolt.Why Correct Hardware Selection Matters
Aircraft are constantly exposed to:- Engine vibration
- Aerodynamic loads
- Repeated take-offs and landings
- Temperature fluctuations
- Operational stresses
- Loosening fasteners
- Joint wear
- Reduced fatigue resistance
- Increased maintenance costs
- Potential safety risks
AN Hardware for Aircraft Builders and Maintenance Professionals
Whether you’re:- Performing routine maintenance
- Replacing worn fasteners
- Completing an engine installation
- Building an aircraft project
- Conducting an annual inspection
Price range: R8.91 through R196.75Select options This product has multiple variants. The options may be chosen on the product page
