Glossary

Aerospace fasteners are fasteners specifically designed, manufactured, tested, and documented for use in aircraft, spacecraft, jet engines, and other flight-critical or aerospace-related assemblies. They include bolts, screws, nuts, rivets, lockbolts, pins, collars, inserts, and other specialized joining hardware used to hold structural and non-structural components together under demanding service conditions. Unlike ordinary commercial fasteners, aerospace fasteners are built for environments where failure can have serious safety, performance, or certification consequences, so selection involves careful consideration of load, vibration, fatigue, corrosion, temperature, weight, and installation method. NASA’s fastener guidance emphasizes that aerospace fastener selection is difficult precisely because the designer must account for temperature, corrosion, vibration, fatigue, preload, and many other factors together.

What makes an aerospace fastener different is not just the shape of the part, but the level of engineering and control behind it. Aerospace fasteners are commonly produced to tightly controlled standards such as NAS and related aerospace specifications, and they are often made in specialized head styles and joint systems intended for shear loading, tension loading, flush aerodynamic surfaces, limited-access installation, or lightweight structural assemblies. Major aerospace fastener suppliers describe these products as precision aircraft fasteners used across commercial and military aircraft, spacecraft, and engines, with configurations that include flush, hex, 12-point, D-head, socket, spline, blind-bolt, and blind-rivet styles.

Materials and quality requirements are also much more stringent than in general industrial hardware. Aerospace fasteners may be made from alloy steel, corrosion-resistant stainless steels, A286, Inconel 718, Waspaloy, titanium, and other superalloys depending on the temperature, strength, corrosion, and weight requirements of the application. They are commonly associated with certification systems such as AS9100 and with inspection, lot control, and traceability requirements that follow the part from raw material through manufacturing and testing. NASA standards explicitly call for complete traceability for certain fastener categories, and aerospace manufacturers commonly highlight full traceability to melt, nondestructive testing capability, and documented quality records as part of normal supply expectations.

In practical use, aerospace fasteners are chosen not simply to “hold parts together,” but to satisfy a certified joint design. That means the fastener has to match the joint geometry, material stack-up, installation access, required clamp load, locking method, maintenance requirements, and damage-tolerance or fracture-control rules that apply to the assembly. FAA guidance warns against using unapproved or substandard aircraft fasteners because their physical properties cannot be substantiated, which captures the core idea well: an aerospace fastener is a highly controlled fastening component intended for aerospace service, where mechanical performance, interchangeability, documentation, and reliability matter just as much as the threads and dimensions themselves.

The National Aerospace Standards (NAS), a type of industry-developed aerospace specification used to define the required dimensions, materials, performance, testing, interchangeability, and quality expectations for aerospace parts, processes, or practices. The Aerospace Industries Association, or AIA, maintains the NAS library and states that these are voluntary standards developed by industry to support the manufacturing and operation of aerospace products. AIA also notes that the NAS library contains more than 1,100 active standards, and that these standards have been developed since 1941.

In practical hardware use, “NAS” is often seen in aerospace fastener part numbers and related component specifications. When a bolt, nut, pin, or other part is described as a NAS item, it generally means it is built to an aerospace standard that is more tightly controlled than ordinary commercial hardware, often with requirements for closer tolerances, higher strength, special geometry, and more rigorous acceptance criteria. AIA’s National Aerospace Standards Committee says its NAS part standards are recognized for meeting the high-strength, close-tolerance, and rigorous acceptance-testing requirements of the aerospace industry. The FAA also groups NAS hardware alongside other accepted aviation standards such as AN and MS when discussing aircraft fasteners and approved hardware.

The term does not refer to one single document. Instead, it refers to a large family of standards covering many aerospace subjects. Some NAS standards define specific parts, such as certain bolts or fittings, while others address broader technical requirements, inspection qualifications, or system practices. For example, AIA recently described NAS410 as a core aerospace standard for qualification and certification of nondestructive testing personnel, which shows that NAS standards are not limited only to fasteners.