Section 1 EO M270.01 – IDENTIFY ASPECTS OF AIRCRAFT MANUFACTURING

When assembling an aircraft, there are multiple aircraft systems included that are manufactured for the aircraft. The following are just a few aircraft systems and components that are manufactured to be used in assembling aircraft.

The development of efficient flight instruments is one of the most important factors that contributed to the growth of the present air transportation system. Prior to World War II, few airplanes were equipped for flight without using ground reference navigation or pilotage.

Aircraft instrument systems include flight instruments that depict the attitude, airspeed, and altitude of the aircraft, making up the aircraft instrument systems. Other instruments provide information such as engine operational parameters and electrical system performance. Other components manufactured to support these systems include electrical wiring and fluid-line plumbing.

Integrated circuits, containing microprocessors and other digital electronics, have revolutionized flight instrumentation and control systems. New generation flight instruments show textual and analog information on brightly coloured displays.

These systems generate and route electricity to various aircraft components such as generators, motors and inverters. There are many manufacturers of these components that make up the airframe electrical systems. Because of the expense of the tools, test equipment and current technical publications, component manufacturers or certified repair stations service many of the electrical components.

Early aircraft were equipped with flight controls and systems that were connected directly to the cockpit controls. As aircraft became more complex, it became necessary to operate systems remotely and the first of these was the brake system. Instead of cables or pushrods operating the brakes, hydraulic pressure was used to solve routing problems and multiple forces on the braking surfaces. While small aircraft continue to use cables or pushrods for operating flight controls, aircraft manufacturers equip larger aircraft with hydraulic or pneumatic control systems for their primary system.

The landing gear of the very first airplanes was not very complex. The Wright Flyer, for instance, took off from a rail and landed on skids. However, soon after the basic problems of flight were solved, attention was turned to providing better control and stability of the aircraft while it was operated on the ground. Retraction systems, shock absorbing and non-shock absorbing systems, aircraft wheels, nose wheel steering systems and aircraft brakes are some of the other components involved in manufacturing the landing gear.

Aircraft fuel systems vary in complexity from the extremely simple systems found in small, single-engine aircraft to the complex systems in large jet transports. Regardless of the type of aircraft, all fuel systems share many of the same common components. Every system has one or more fuel tanks, tubing to carry the fuel from the tank(s) to the engine(s), valves to control the flow of fuel, provisions for trapping water and contaminants and a method for indicating the fuel quantity.

The techniques and materials used in the early years of aviation were quite primitive by modern standards. The Wright brothers’ “Flyer,” for example, was made from steel, wire, cable, silk and wood. However, as aircraft development advanced, a breakthrough occurred in the aircraft aluminum industry. Metallurgists found that mixing, or alloying aluminum with other metals resulted in a much stronger material. In fact, alloying increased the tensile strength of pure aluminum from about 13 000 pounds per square inch (psi) to a tensile strength of 65 000 psi or greater, which is equivalent to structural steel. As the need for aluminum alloys grew, manufacturers continued to refine them to produce materials with better corrosion resistance and greater strength.

Today, military aircraft are constructed of about 65 percent aluminum and 35 percent of other alloys, including titanium, inconel, silver and nickel. Civilian aircraft are approximately 80 percent aluminum alloy and 20 percent other alloys.

Today, military aircraft are constructed of about 65 percent aluminum and 35 percent of other alloys, including titanium, inconel, silver and nickel. Civilian aircraft are approximately 80 percent aluminum alloy and 20 percent other alloys.

Much of the metal used on today’s aircraft contains no iron. The term that describes metals which have elements other than iron as their base is non-ferrous. Aluminum, titanium, nickel and copper are some of the more common non-ferrous metals used in aircraft manufacturing and repair.

Aluminum and Its Alloys. Pure aluminum lacks sufficient strength to be used for aircraft construction. However, its strength increases considerably when it is alloyed, or mixed with other compatible metals (e.g. when aluminum is mixed with copper or zinc, the resultant alloy is as strong as steel with only one third the weight).

Titanium. Titanium and its alloys are lightweight metals with very high strength. Pure titanium weighs 0.163 pounds per cubic inch (4.5 g/cm³), which is about 50 percent lighter than stainless steel, yet it is approximately equal in strength to iron. Furthermore, pure titanium is soft and ductile with a density between that of aluminum and iron.

Nickel. Aircraft technicians need to be familiar with two nickel alloys. They are monel and inconel.

Copper. Neither copper nor its alloys find much use as structural materials in aircraft construction. However, due to its excellent electrical and thermal conductivity, copper is the primary metal used for electrical wiring.

Graphite, Kevlar and fibreglass are composite materials used to form various types of aircraft structures.

Graphite Fibres. Graphite fibres are manufactured by heating and stretching rayon fibres. This produces a change in the fibres’ molecular structure that makes it extremely lightweight, strong, and tough.

Kevlar Fibre. Kevlar fibre is one of the most commonly used cloth-reinforcing fabrics. In its cloth form, Kevlar is a soft yellow organic fibre that is extremely light, strong and tough. Its great impact resistance makes it useful in areas where damage from sand or other debris can occur. These areas include around landing gear and behind propellers. Kevlar is rather difficult to work with however, and does not perform well under compressive loads.

Glass Fibre/Fibreglass. Fibreglass greatly enhances the strength and durability of thermosetting resin, which is a material that hardens when heated. For high strength requirements, the glass fibres are woven into a cloth. On the other hand, where cost is of greater importance than strength, the fibres are gathered into a loose mat which is saturated with resin and moulded into a desired shape.