Question

What are some aircraft aging problems? How can you as an Aviation Maintenance Manager monitor problems that relate to aircraft fatigue? What are some techniques to prolong the lifespan of aircraft? Which section in an airline organization is responsible for reducing aircraft fatigue? Please be specific with your response and share examples as appropriate.

Answer 1

The two key processes that lead to aircraft ageing are fatigue and corrosion. These processes generally affect the aircraft structure, but can also affect wiring, flight controls, powerplants, and other components. Fatigue and corrosion can work independently from one another, or they can interact. The interaction between fatigue and corrosion can increase the rate of ageing to a greater extent than that due to either process alone.

Fatigue predominately takes place in metal components, but it can also affect non-metallic materials. Fatigue occurs through cyclic loading patterns, where a component is repeatedly loaded. Bending a metal paper clip backwards and
forwards is an example of fatigue; the paper clip will not break if only bent once, however, if it is repeatedly loaded, it will eventually break. Fatigue failures will often take place at loads much lower than the materials ultimate strength.
Generally, the initiation point for fatigue will be a microscopic crack that forms at a location of high stress, such as a hole, notch, or material imperfection. The crack will then grow as loads are repeatedly applied. If not detected and treated, the crack will eventually grow to a critical size and failure will occur at loads well below the original strength of the material.
The relationship between repetitive loading and fatigue crack growth, creates a link between fatigue related ageing, the number of flight cycles, and the number of flight hours that an aircraft has accumulated.
Aircraft components that are susceptible to fatigue include most structural components such as the wings, the fuselage, and the engine.

During initial manufacturing the research department is responsible for designing the aircraft to withstand fatigue. During operations the fatigue risk management of aviation maintenance will try to rectify the problems due to fatigue.