Chapter Objective: Upon completion of this chapter, you will have a working knowledge of the various types of aircraft hardware and seals used in naval aircraft and the procedures for maintaining their security.

Because of the small size of most hardware items, their importance is often overlooked. The safe and efficient operation of any aircraft is greatly dependent upon correct selection and use of aircraft structural hardware and seals. This chapter discusses these various items. It also provides information that can aid you in the selection and correct use of aircraft structural hardware and seals. Aircraft hardware is discussed in detail in the Manual, NAVAIR 01-1A-8.

Aircraft hardware is usually identified by its specification number or trade name. Threaded fasteners and rivets are usually identified by AN (Air Force-Navy), NAS (national aircraft standard), and MS (military standard) numbers. Quick-release fasteners are usually identified by factory trade names and size designations. 

To obtain aircraft hardware from supply, the specification numbers and the factory part numbers are changed into stock numbers (NSN). This is done by using a part number cross-reference index.

Learning Objective: Identify the various types of structural hardware used in the construction and repair of naval aircraft.

The term aircraft structural hardware refers to many items used in aircraft construction. You should be concerned with such hardware as rivets, fasteners, bolts, nuts, screws, washers, cables, guides, and you should be familiar with common electrical system hardware.

This section starts with a discussion of rivets used in modern aircraft. The fact that there are thousands of rivets in an airframe is an indication of how important riveting is in the AM rate. A glance at any aircraft will show the thousands of rivets in the outer skin alone. Besides the riveted skin, rivets are also used for joining spar sections, for holding rib sections in place, for securing fittings to various parts of the aircraft, and for fastening bracing members and other parts together. Rivets that are satisfactory for one part of the aircraft are often unsatisfactory for another part. Therefore, it is important that you know the strength and driving properties of the various types of rivets and how to identify them, as well as how to drive or install them.

Solid rivets are classified by their head shape, by the material from which they are manufactured, and by their size. Rivet head shapes and their identifying code numbers are shown in figure 2-1. The prefix MS identifies hardware that conforms to written military standards. The prefix AN identifies specifications that are developed and issued under the joint authority of the Air Force and the Navy.