Types of Bolts and Screws Explained for Aircraft

In the aviation industry, even the smallest component plays a major role in ensuring flight safety and aircraft performance. Among these essential components, Bolts and Screws are some of the most critical fastening hardware used in aircraft manufacturing, maintenance, and repair. From securing engine components to holding together structural assemblies, aircraft fasteners must withstand extreme vibration, pressure, temperature changes, and stress.

Unlike ordinary industrial fasteners, aviation-grade bolts and screws are engineered with high precision and strict compliance standards. Understanding the different types of aircraft bolts and screws helps maintenance teams, engineers, and buyers choose the correct hardware for safe and efficient aircraft operations.

Why Aircraft Bolts and Screws Are Different

Aircraft hardware is designed according to military and aerospace standards such as AN (Air Force-Navy), NAS (National Aerospace Standards), and MS (Military Standard). These standards ensure that every bolt or screw meets strict performance requirements.

The wrong fastener can lead to structural failure, vibration issues, or costly maintenance problems. That is why selecting the right Bolts and Screws is essential for aircraft reliability and airworthiness.

Common Types of Aircraft Bolts

1. AN Bolts (Air Force-Navy Bolts)

AN bolts are among the most commonly used aircraft fasteners. They are manufactured from high-strength steel, corrosion-resistant steel, or aluminum alloys.

These bolts are typically used in:

• Structural connections
• Aircraft frames
• Engine mounts
• Landing gear assemblies

AN bolts are identified by a drilled shank or drilled head, allowing safety wire or cotter pin installation to prevent loosening during flight vibrations.

2. NAS Bolts

NAS bolts are stronger and more precise than standard AN bolts. They are designed for high-stress aerospace applications where greater shear strength is required.

Common applications include:

• Wing structures
• Turbine engine systems
• Flight control assemblies

NAS bolts usually feature tighter tolerances and are often used in modern commercial and military aircraft.

3. Clevis Bolts

Clevis bolts are special-purpose fasteners designed primarily for shear loads rather than tension loads. They are often used in aircraft control systems where movement between connected parts is required.

You can commonly find them in:

• Rudder controls
• Aileron linkages
• Pedal assemblies

Their slotted heads allow easy installation and removal.

4. Eye Bolts

Eye bolts include a looped head designed for attaching cables, springs, or linkage systems. In aviation, they are often used in control cable systems and tension assemblies.

Because they handle continuous movement and stress, aircraft eye bolts must be inspected regularly for cracks or wear.

Types of Aircraft Screws

Aircraft screws are used extensively in non-structural and semi-structural applications. Different screw types are selected based on accessibility, load requirements, and environmental conditions.

1. Machine Screws

Machine screws are widely used throughout aircraft interiors and avionics systems. They are smaller than bolts and typically threaded into nuts or threaded components.

Common uses include:

• Instrument panels
• Electrical systems
• Interior cabin components

They are available in various head styles including round head, flat head, and pan head configurations.

2. Structural Screws

Structural screws are designed for heavier-duty aerospace applications. These screws provide high tensile strength and are often installed where bolt usage is impractical.

They are frequently found in:

• Aircraft skin panels
• Access doors
• Structural brackets

Structural screws are manufactured with precision threads for secure fastening under vibration conditions.

3. Self-Locking Screws

Aircraft experience constant vibration during operation, which can loosen traditional fasteners over time. Self-locking screws are specifically designed to resist loosening without additional locking devices.

These screws are commonly used in:

• Engine compartments
• Electronic assemblies
• Hydraulic systems

Their locking feature improves safety and reduces maintenance frequency.

4. Sheet Metal Screws

Sheet metal screws are primarily used for fastening thin metal layers and lightweight panels. They are commonly found in aircraft interiors and non-load-bearing assemblies.

Applications include:

• Cabin panels
• Fairings
• Access covers

Because they cut their own threads during installation, they allow quick assembly and replacement.

Materials Used in Aircraft Bolts and Screws

The material selection for aviation fasteners is just as important as the fastener type itself. Aircraft hardware must offer strength while minimizing overall aircraft weight.

Common aerospace fastener materials include:

• Stainless steel
• Titanium
• Alloy steel
• Aluminum alloys
• Corrosion-resistant steel

Titanium fasteners are especially popular in modern aircraft because they combine lightweight properties with excellent strength and corrosion resistance.

Importance of Proper Fastener Selection

Choosing the correct Bolts and Screws for aircraft applications is not only about fitment — it directly impacts safety, durability, and maintenance efficiency.

Several factors must be considered:

• Load capacity
• Corrosion resistance
• Temperature tolerance
• Vibration resistance

Compatibility with surrounding materials

Using incorrect or low-quality fasteners can result in:

• Structural fatigue
• Fastener loosening
• Corrosion damage
• Increased maintenance costs
• Safety hazards

This is why aviation professionals rely on certified aerospace parts suppliers for authentic aircraft hardware.

How to Identify Aircraft Bolts and Screws

Aircraft fasteners are usually marked with identification codes that indicate their material, strength, and standard type.

For example:

• AN markings indicate standard aircraft bolts
• NAS markings indicate aerospace-grade precision hardware
• Drilled heads often indicate safety-wire compatibility

Understanding these markings helps technicians ensure proper installation and replacement during maintenance operations.

Where to Buy Reliable Aircraft Bolts and Screws

When sourcing aviation hardware, quality assurance is critical. Buyers should always work with trusted aviation parts distributors that provide traceable and certified components.

Reliable suppliers typically offer:

• FAA-compliant hardware
• Traceability documentation
• Aerospace-grade materials
• Large inventory availability
• Fast global shipping

Whether you need structural fasteners for commercial aircraft or maintenance hardware for private aviation, choosing the right supplier ensures long-term reliability and compliance.

Final Thoughts

Aircraft rely on thousands of precision-engineered Bolts and Screws to maintain structural integrity and operational safety. From AN bolts and NAS bolts to machine screws and self-locking screws, every fastener serves a specialized purpose within an aircraft system. Understanding the different types of aviation fasteners helps maintenance professionals, engineers, and buyers make informed decisions when selecting aerospace hardware. Investing in certified, high-quality fasteners not only improves aircraft performance but also enhances safety and reduces long-term maintenance risks. As aviation technology continues to evolve, modern aircraft fasteners will become even more advanced, lightweight, and durable — making them an essential component of the future of flight.