GCAA AME Licence Exam key terms

A legally binding notice issued by an authority requiring inspection, modification, or restriction on aircraft or components to correct an unsafe condition. Compliance is mandatory and must be recorded in the maintenance records.

The set of processes and records that keep an aircraft in a condition meeting its type design and safe to operate throughout its service life, including maintenance, defect control, and compliance with directives.

A certification, signed by authorised personnel, stating that specified maintenance has been completed and the aircraft or component is fit for return to service within stated limitations.

A formal declaration signed by a licensed engineer confirming that maintenance work has been carried out satisfactorily and the item is airworthy, with any limitations or deferred items clearly stated.

An organisation holding authority approval to perform maintenance, inspection, or repair on aircraft or components under defined scope, facilities, personnel, and quality system requirements.

An approval document issued by the state of design confirming that an aircraft, engine, or propeller type meets the applicable airworthiness design standards for its intended use.

A document from the manufacturer advising operators of recommended inspections, modifications, or procedures, often not mandatory in itself but frequently made mandatory by an airworthiness directive.

Planned systematic activities, including audits and process controls, that provide confidence that maintenance work consistently meets the required standards and regulatory requirements.

The study of how human capabilities, limitations, and behaviour interact with the maintenance environment, aimed at reducing error through design, procedures, training, and awareness of factors such as fatigue and complacency.

A commonly taught list of twelve maintenance error precursors, including fatigue, pressure, distraction, lack of communication, and complacency, used to help engineers recognise and manage error-inducing situations.

A framework describing human factors as interactions between Software, Hardware, Environment, and Liveware, with the central Liveware being the person and the surrounding blocks the interfaces that can cause error.

The periodic verification and adjustment of a torque tool against a traceable standard so that the applied torque remains within specified accuracy limits, with results recorded and a calibration label fitted.

The chain of documented comparisons linking a measurement instrument's readings back to national or international measurement standards, proving the instrument's accuracy is known and defensible.

Inspection methods such as dye penetrant, magnetic particle, eddy current, ultrasonic, and radiography that reveal defects in materials or structures without damaging the item being inspected.

The electrochemical deterioration of a metal through reaction with its environment, producing material loss or cracking; controlled by protective coatings, sealants, inspection, and removal of contaminants such as moisture and salt.

Corrosion accelerated when two dissimilar metals are in electrical contact in the presence of an electrolyte, causing the more active metal to corrode preferentially; prevented by isolation, sealants, and compatible material selection.

Cracking caused by the combined action of a sustained tensile stress and a corrosive environment, often occurring in high-strength alloys and detectable by careful inspection of susceptible areas.

Progressive structural damage from repeated or fluctuating loads, leading to crack initiation and growth, particularly at stress concentrations such as holes, fillets, and fastener rows.

A local increase in stress caused by a change in section, hole, notch, or sharp corner, which raises the likelihood of fatigue cracking at that location.

A design and maintenance philosophy accepting that structures may contain undetected cracks, and setting inspection intervals so that any crack is found and repaired before it becomes critical.

A structural arrangement in which load paths are duplicated so that failure of one member does not cause loss of the structure, improving safety and damage tolerance.

A permanent fastener installed by deforming its shank to clamp materials together; the shop head and manufactured head must meet specified dimensions, and rivet spacing and edge distance affect joint strength.

A two-part threaded fastener using a collar that shears at a predetermined torque, giving consistent clamp-up; installation requires correct grip length and hole preparation.

The controlled application of a specified turning force to a fastener to achieve correct clamp-up, using calibrated tools and following the manufacturer's values, sequences, and friction conditions.

For steady incompressible flow, an increase in fluid velocity is accompanied by a decrease in static pressure, explaining lift generation and venturi and pitot-static behaviour.

The angle between the wing chord line and the relative airflow; increasing it raises lift up to the critical angle, beyond which the wing stalls.

The angle of attack at which airflow separates from the wing and lift reaches a maximum, after which the wing stalls regardless of airspeed or attitude.

The ratio of lift produced to aircraft weight, expressed in g; it increases in turns and manoeuvres and determines the structural loads the airframe must withstand.

A pressure system supplying pitot (total) pressure and static pressure to airspeed indicator, altimeter, and vertical speed indicator; blockage or leakage causes erroneous instrument indications.

An instrument that converts static pressure into indicated altitude using a pressure reference set by the subscale; incorrect setting or static blockage leads to misleading altitude information.

An instrument showing the difference between pitot and static pressure, calibrated to display airspeed; errors arise from position error, compressibility, and system blockage.

A conductive distribution bar that receives electrical power from generators or batteries and feeds multiple circuits through protective devices, allowing shared supply and isolation.

A resettable protective device that opens a circuit automatically when current exceeds a rated value, protecting wiring and equipment from overheating and fire.

The electrical connection of metallic parts to the aircraft structure to provide a low-resistance return path and prevent static build-up, sparking, and interference to avionics.

A powerplant in which air is compressed, fuel burned in the combustor, and expanding gases drive a turbine that turns the compressor and produces thrust or shaft power.

A severe aerodynamic instability in which airflow reverses momentarily through the compressor, causing loud bangs, vibration, and power loss; avoided by bleed valves and careful handling.

The temperature of gases leaving the turbine, used to monitor engine health and set take-off and cruise limits; excessive EGT indicates problems such as hot section distress or fuel scheduling faults.

Abnormal, explosive combustion in a piston engine where the fuel-air charge ignites rapidly and unevenly, causing high cylinder pressures, knocking, and potential engine damage.

Ignition of the fuel-air charge before the spark occurs, often caused by hot spots such as glowing deposits or overheated plugs, leading to rough running and possible engine damage.

A self-contained engine-driven ignition device producing high-voltage pulses for spark plugs without needing an external electrical supply; dual magnetos provide redundancy.