18.1. AIRPLANE MAINTENANCE

An airplane is delivered from the manufacturer to the airline in an airworthy condition with all airplane systems in a fully functional state. Because an airplane is continuously utilized for revenue flights, it is physically subjected to structural fatigue induced by vibration, aerodynamic loads, flight maneuver loads, engine thrust loads, takeoff loads, landing loads, ground loads (taxi and towing), pressurization cycles, and thermal cycles (Figure 18.1). The operating environment can cause physical damage to the airplane, such as corrosion resulting from water, saltwater, or chemicals. Natural phenomena such as hailstorms, lightning strikes, sandstorms, and volcanic ash can cause physical damage to the airplane. Man-made objects such as ground equipment can also cause damage to the airplane. Objects such as rocks or bolts can cause foreign object damage (FOD). Even birds in flight can extensively damage an airplane. However, the most prevalent causes for the physical deterioration of the airplane structure are fatigue and corrosion. Through normal continuous usage, airplane systems will experience degradation and eventual reduced performance. Airplane maintenance is essential to ensure full functionality of airplane systems and the airworthiness of the airplane.

Figure 18.1: Physical...