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Aircraft Mechanics

The Job

The work of aircraft mechanics employed by the commercial airlines may be classified into two categories, that of line maintenance mechanics and overhaul mechanics.

Line maintenance mechanics are all-around craft workers who make repairs on all parts of the plane. Working at the airport, they make emergency and other necessary repairs in the time between when aircraft land and when they take off again. They may be told by the pilot, flight engineer, or head mechanic what repairs need to be made, or they may thoroughly inspect the plane themselves for oil leaks, cuts or dents in the surface and tires, or any malfunction in the radio, radar, and light equipment. In addition, their duties include changing oil, cleaning spark plugs, and replenishing the hydraulic and oxygen systems. They work as fast as safety permits so the aircraft can be put back into service quickly.

Overhaul mechanics keep the aircraft in top operating condition by performing scheduled maintenance, making repairs, and conducting inspections required by the FAA. Scheduled maintenance programs are based on the number of hours flown, calendar days, or a combination of these factors. Overhaul mechanics work at the airline's main overhaul base on either or both of the two major parts of the aircraft: the airframe, which includes wings, fuselage, tail assembly, landing gear, control cables, propeller assembly, and fuel and oil tanks; or the power plant, which may be a radial (internal combustion), turbojet, turboprop, or rocket engine.

Airframe mechanics work on parts of the aircraft other than the engine, inspecting the various components of the airframe for worn or defective parts. They check the sheet-metal surfaces, measure the tension of control cables, and check for rust, distortion, and cracks in the fuselage and wings. They consult manufacturers' manuals and the airline's maintenance manual for specifications and to determine whether repair or replacement is needed to correct defects or malfunctions. They also use specialized computer software to assist them in determining the need, extent, and nature of repairs. Airframe mechanics repair, replace, and assemble parts using a variety of tools, including power shears, sheet-metal breakers, arc and acetylene welding equipment, rivet guns, and air or electric drills.

Aircraft power plant mechanics inspect, service, repair, and overhaul the engine of the aircraft. Looking through specially designed openings while working from ladders or scaffolds, they examine an engine's external appearance for problems such as cracked cylinders, oil leaks, or cracks or breaks in the turbine blades. They also listen to the engine in operation to detect sounds indicating malfunctioning components, such as sticking or burned valves. The test equipment used to check the engine's operation includes ignition analyzers, compression checkers, distributor timers, and ammeters. If necessary, the mechanics remove the engine from the aircraft, using a hoist or a forklift truck, and take the engine apart. They use sensitive instruments to measure parts for wear and use X-ray and magnetic inspection equipment to check for invisible cracks. Worn or damaged parts are replaced or repaired. The mechanics then reassemble and reinstall the engine.

Aircraft mechanics adjust and repair electrical wiring systems and aircraft accessories and instruments; inspect, service, and repair pneumatic and hydraulic systems; and handle various servicing tasks, such as flushing crankcases, cleaning screens, greasing moving parts, and checking brakes.

Mechanics may work on only one type of aircraft or on many different types, such as jets, propeller-driven planes, and helicopters. For greater efficiency, some specialize in one section, such as the electrical system, of a particular type of aircraft. Among the specialists, there are airplane electricians; pneumatic testers and pressure sealer-and-testers; aircraft body repairers and bonded structures repairers, such as burnishers and bumpers; and air-conditioning mechanics, aircraft rigging and controls mechanics, plumbing and hydraulics mechanics, and experimental-aircraft testing mechanics. Avionics technicians are mechanics who specialize in the aircraft's electronic systems.

Mechanics who work for businesses that own their own aircraft usually handle all necessary repair and maintenance work. The planes, however, generally are small and the work is less complex than in repair shops.

In small, independent repair shops, mechanics must inspect and repair many different types of aircraft. The airplanes may include small commuter planes run by an aviation company, private company planes and jets, private individually owned aircraft, and planes used for flying instruction.