BR-ANAC-AVI key terms

A legally binding notice issued by an aviation authority requiring inspection, repair, or modification of an aircraft or component to correct an unsafe condition. Compliance is mandatory for continued lawful operation.

A document confirming that an individual aircraft conforms to its approved type design and is safe to operate within specified limitations. It must remain valid for the aircraft to be flown legally.

The set of maintenance, inspection, and record-keeping processes that keep an aircraft in a condition meeting its type design and safe operating standards throughout its service life.

Rules allowing flight in which the pilot is responsible for seeing and avoiding other traffic and terrain, subject to specified minimum visibility and cloud separation requirements.

Rules governing flight conducted under instrument conditions, requiring the pilot to follow air traffic control clearances and published procedures for navigation and separation from obstacles and other aircraft.

Weather conditions in which visibility and distance from cloud meet specified minima, permitting flight under visual flight rules. These minima vary with airspace class and altitude.

Weather conditions in which visibility or cloud separation is below the required minima for visual flight, so the flight must be conducted under instrument flight rules.

The angle between the wing's chord line and the relative airflow approaching it. Increasing this angle raises lift up to a critical point, beyond which the airflow separates and the wing stalls.

The angle of attack at which airflow separation begins over the wing, producing maximum lift and beyond which the wing stalls. It is essentially independent of weight, speed, and bank angle.

A condition in which the wing exceeds its critical angle of attack, causing airflow separation, loss of lift, and often buffet or a sinking sensation. Recovery requires reducing the angle of attack.

The ratio of total lift produced to the aircraft's weight, expressed in g units. It increases in turns and manoeuvres, raising stall speed and structural stress on the airframe.

A stall occurring at a higher speed than normal because increased load factor, typically in a steep turn or abrupt pull-up, raises the speed at which the critical angle of attack is reached.

The direction of air passing over the aircraft as a result of its motion through the air mass. It determines angle of attack and thus the lift and drag generated.

Drag created as a by-product of generating lift, caused by pressure differences around the wing producing vortices. It increases with angle of attack and decreases as speed rises.

The point at which the aircraft's total weight is considered to act. Its position must remain within approved forward and aft limits for safe control and performance.

The process of calculating the aircraft's total mass and centre of gravity position to confirm both lie within certified limits before flight, ensuring safe handling and performance.

A document showing the aircraft's zero-fuel and take-off mass, the distribution of that mass, and the resulting centre of gravity position, signed by the responsible person before departure.

The highest mass at which the aircraft is certified to begin its take-off run. Exceeding it invalidates performance and structural assurances and is prohibited.

The altitude in the standard atmosphere at which air density equals the actual density at a given location. High values reduce engine power, propeller thrust, and wing lift, lengthening take-off runs.

The altitude indicated when the altimeter subscale is set to standard pressure, 1013.25 hPa. It is used for performance calculations and for flight above the transition altitude.

The pressure value entered on the altimeter subscale so that it indicates height above a chosen reference, such as mean sea level or an aerodrome elevation.

The altitude at or below which the aircraft's altitude is expressed in terms of the local altimeter setting, and above which the standard setting is used.

A condition in which body tissues receive insufficient oxygen, causing impaired judgement, euphoria, and loss of consciousness. It can occur at relatively low altitudes in unpressurised aircraft.

The period after loss of adequate oxygen supply during which a person can still take purposeful corrective action before becoming incapacitated. It shortens rapidly as altitude increases.

A mistaken perception of the aircraft's position or motion relative to the earth, usually caused by misleading sensory cues in the absence of reliable visual references. It can lead to loss of control.

Abnormally rapid or deep breathing that lowers carbon dioxide in the blood, producing dizziness, tingling, and faintness. Its symptoms resemble hypoxia and it is often triggered by stress or fear.

A false sensory interpretation, often visual or vestibular, that leads a pilot to misjudge altitude, distance, or aircraft attitude, particularly during approach and landing in poor visual conditions.

The altimeter subscale setting that, when entered, causes the altimeter to indicate elevation above mean sea level at the reporting station's location.

The altimeter subscale setting that makes the altimeter read zero on the ground at the reporting station, so it indicates height above that reference point rather than above sea level.

A defined reference atmosphere with sea-level temperature of 15 degrees Celsius, pressure of 1013.25 hPa, and specified lapse rates, used to compare and compute aircraft performance.

The accumulation of ice on aircraft surfaces when flying through supercooled water droplets. It adds weight, disrupts airflow, and can severely degrade lift and control effectiveness.

Ice forming in a carburettor due to fuel vaporisation and venturi cooling, which can occur at outside temperatures well above freezing and cause rough running or engine failure.

The altitude at which the air temperature falls to zero degrees Celsius. It marks the lower boundary of conditions favourable to airframe icing in cloud.

The shortest path between two points on the surface of a sphere, formed by the intersection of the sphere with a plane passing through its centre.

A line of constant true track crossing all meridians at the same angle. It is not the shortest route but simplifies navigation because a constant heading can be maintained.

The angular difference at a given location between true north and magnetic north. It is applied when converting between true and magnetic directions and varies with position and time.

The angular error in a magnetic compass caused by the aircraft's own magnetic fields and electrical equipment. It differs by heading and is recorded on a compass correction card.

Disturbed air, chiefly counter-rotating wingtip vortices, left behind a moving aircraft. It is strongest from heavy, slow, clean aircraft and can cause violent upset in following traffic.

A designated position on a taxiway or runway at which an aircraft must stop and wait unless cleared to proceed, protecting a runway or obstacle from unauthorised entry.

An authorisation from air traffic control for an aircraft to proceed under specified conditions. It does not relieve the pilot of responsibility for safety or terrain separation.

The pilot's repetition of a clearance or instruction to air traffic control to confirm it was received and understood correctly, required for safety-critical items such as route and altitude instructions.

A standard set of spoken words, such as Alpha, Bravo, Charlie, assigned to each letter to ensure unambiguous transmission of letters and identifiers over radio.

A four-digit number set on the aircraft transponder to identify it on air traffic control radar displays, often assigned by controllers for identification or special purposes.