Aircraft maintenance is the performance of tasks required to ensure the continuing airworthiness of an aircraft or aircraft part, including overhaul, inspection, replacement, defect rectification, and the embodiment of modifications, compliance with airworthiness directives, and repair.
The maintenance of aircraft is highly regulated, in order to ensure safe and correct functioning during flight. In civil aviation, national regulations are coordinated under international standards, established by the International Civil Aviation Organization (ICAO).
The ICAO standards have to be implemented by local airworthiness authorities to regulate the maintenance tasks, personnel, and inspection system. Maintenance staff must be licensed for the tasks they carry out.
Aircraft Maintenance Technician Schools (AMTS)
An AMTS is an educational facility certificated by FAA to train prospective aircraft mechanics for careers in the airline industry, in aviation maintenance facilities, and in commercial and General Aviation (GA). 14 CFR part 147 specifies requirements for the certification and operation of an AMTS.
The regulation includes both the curriculum requirements and the operating rules for all certificated AMTSs. The knowledge, skills, and abilities required of mechanics are considerable and demand high-quality training. Therefore, FAA requires high standards from the AMTS.
Aircraft mechanic systems are those required to operate an aircraft efficiently and safely, their complexity varies with the type of aircraft.
1- Hydraulic systems
Aircraft hydraulic systems are required for high-speed flight and large aircraft to convert the crews’ control system movements to surface movements. The hydraulic system is also used to extend and retract the landing gear, operate flaps and slats, and operate the wheel brakes and steering systems.
Hydraulic systems consist of engine-driven pumps, fluid reservoirs, oil coolers, valves, and actuators. Redundancy for safety is often provided by the use of multiple, isolated systems.
2- Aircraft Electrical system
Aircraft electrical systems generally consist of a battery, generator or alternator, switches, circuit breakers, and instruments such as voltmeters and ammeters. A backup electrical supply can be provided by a ram air turbine (RAT) or Hydrazine powered turbines.
3- Fuel systems
An aircraft fuel system is designed to store and deliver aviation fuel to the propulsion system and auxiliary power unit (APU) if equipped. Fuel systems differ greatly due to the different performances of the aircraft in which they are installed.
4- Pneumatic systems
The aircraft pneumatic systems are those that require air to perform their function. The air may be pressurized and used to perform the functions of pressurization, cooling, or actuation, or it may be used as a sensing system to provide information about the speed and altitude of the aircraft.
Pressurized air can be obtained from the aircraft engines and is used to provide energy to perform a number of functions on the aircraft. Although most power transfer systems make use of hydraulic and electrical power sources of energy, there are a number of functions that still draw their supply of energy from engine bleed air.
In addition, there is a system that uses atmospheric air pressure to provide a source of air data to instruments and flight control systems.
5- Landing gear
The landing gear, which is also called the undercarriage, is a complex system consisting of structural members, hydraulics, energy absorption components, brakes, wheels, and tires. Additional components attached to and functioning with the landing gear may include steering devices and retracting mechanisms.
Of the many components, it is the structural members that support the heavy landing loads and stop the landing gear from collapsing under the aircraft’s weight. The materials must be strong enough to support heavy take-off weight when an aircraft has a full load of fuel and the high impact loads on landing.
Landing gear materials must therefore have high static strength, good fracture toughness, and fatigue strength, and the most commonly used materials are high-strength steel and titanium alloy.
What Does an Aircraft Mechanic Do?
Aircraft mechanics supervise, manage, and perform maintenance, inspections, and repairs on aircraft. It is their top priority to ensure aircraft safety and airworthiness for passenger travel, air cargo and shipping, and much more!
Highly trained and federally certified, aircraft mechanics are commonly referred to as airframe and powerplant (A&P) mechanics or aviation maintenance technicians.
To work on aircraft, individuals must undergo rigorous training and testing to become A&P certified – obtaining the licenses required by the Federal Aviation Administration (FAA) to perform aviation maintenance.
A&P ratings are vital for a career foundation as an aircraft mechanic. They are often required for other career pathways or advancement opportunities as well.
The Ins and Outs: Inspecting Aircraft, Repairs, and Scheduled Maintenance
Before performing repairs or maintenance, aircraft mechanics first inspect for damage or imperfections. Inspection procedures include testing aircraft parts with diagnostic equipment, reviewing completed work to ensure that it meets performance standards, and examining replacement parts for defects.
Once inspections are complete, mechanics may have to perform repairs or unscheduled maintenance. Mechanics often repair wings, brakes, electrical systems, engines, the body, and other aircraft components using hand tools, power tools, and other industry-specific equipment.
Mechanics also perform preventative care, or scheduled maintenance, at regular intervals. The time between maintenance checks could be hours flown, days since the last inspection, amounts of flights, or a combination of these factors.
Types of scheduled maintenance checks include line maintenance, ‘A’ checks, ‘B’ checks, ‘C’ checks, and ‘D’ checks. A part of scheduled maintenance includes inspections and may require unscheduled repairs.
Line maintenance checks are the most routine maintenance service performed on aircraft. They ensure an aircraft is airworthy and safe to continue service. Tasks include inspecting the wheels, brakes, and fluid levels (oil, hydraulics).
Aircraft need line maintenance every 24 to 60 hours of accumulated flight time, depending on the aircraft operator’s assessment.
Airframe and Powerplant Licensure
The FAA certificate or A&P licensure is necessary for technicians to operate, repair, and inspect aircraft without the supervision of a certified mechanic. The National Aviation Academy (NAA), it’s also required to approve equipment for return to service.
Although obtaining both licenses aren’t required to practice as an aircraft mechanic, mechanics with only one of the two licenses will be limited to working on the part of the aircraft covered by their license. Additionally, some specializations require both, such as airframe and powerplant mechanics.
The Federal Aviation Administration requires applicants to pass oral, practical, and written exams covering 43 technical subjects to receive their airframe and powerplant licensure. Applicants must also be at least 18 years old, proficient in English, and possess a high school diploma or GED.