ANAC Commercial Pilot Airplane (PCA) key terms

The greatest total mass an aircraft is certified to have at the start of the take-off run, including structure, fuel, crew, passengers and baggage. Exceeding it invalidates performance and structural assumptions.

The mass of the aircraft as delivered plus optional equipment, unusable fuel and full operating fluids, excluding crew, usable fuel and payload. It is the starting point for every weight and balance computation.

The mass of occupants, baggage and cargo that produces revenue or mission value, obtained by subtracting basic empty weight and usable fuel from the actual take-off mass.

The point through which the total weight of the aircraft is considered to act. It must remain inside a certified forward and aft envelope for control and stability to be assured.

The certified range of center of gravity positions, expressed as limits along the longitudinal axis, within which the aircraft may be operated at each weight. Loading outside it is prohibited.

The horizontal distance from a chosen reference datum to the point where a mass acts. Multiplying a mass by its arm gives the moment used to locate the loaded center of gravity.

The altitude in the standard atmosphere at which the current air density would occur. High values reduce engine power, propeller thrust and wing lift, lengthening take-off and climb.

The altitude indicated when the altimeter subscale is set to 1013.25 hPa, derived from static pressure alone. It is the input for most performance charts.

The decision speed at which, after an engine failure on a multi-engine aircraft, the take-off can still be safely continued or rejected within the available runway.

The rotation speed at which the pilot applies back pressure to raise the nose and initiate the transition from ground roll to the climb attitude.

The take-off safety speed to be attained by 35 feet above the runway with one engine inoperative, providing the minimum climb gradient required by certification.

The highest density altitude at which an aircraft can still climb at a specified minimum rate, typically 100 feet per minute for piston airplanes.

The runway length at which the accelerate-stop distance equals the accelerate-go distance, giving the shortest field from which a given take-off weight is legal.

The acute angle between the wing chord line and the relative airflow. Lift increases with angle of attack until the critical angle, beyond which the wing stalls.

The angle of attack at which airflow separates from the upper wing surface and lift reaches its maximum. A wing stalls at this angle regardless of speed, weight or attitude.

Drag created as a by-product of lift, caused by the spanwise flow and wingtip vortices that deflect air downward. It decreases with speed and increases with weight and load factor.

The ratio of total lift to weight, expressed in g. It rises in turns and pull-ups and directly raises the stall speed and structural stress on the airframe.

The lowest indicated airspeed at which an aircraft can maintain level flight in a given configuration. It increases with weight, load factor and forward center of gravity.

The distance between the center of gravity and the aerodynamic center, expressed as a fraction of mean chord. A larger margin gives more pitch stability but more trim drag.

The altimeter subscale setting that makes the instrument read aerodrome elevation when the aircraft is on the ground, referenced to mean sea level pressure.

The altimeter subscale setting that makes the instrument read zero on the aerodrome, so the indication is height above the aerodrome rather than altitude above sea level.

The altitude above which pilots set the standard pressure setting of 1013.25 hPa and express vertical position as flight levels, instead of using local QNH.

The lowest flight level available for use above the transition altitude, chosen so that it provides at least the required separation above the transition altitude.

The convention assigning magnetic tracks 000 to 179 degrees to odd flight levels and 180 to 359 degrees to even flight levels, so opposite-direction traffic is vertically separated.

A surface of constant pressure shown on the altimeter when set to 1013.25 hPa, expressed in hundreds of feet, used above the transition altitude for traffic separation.

Visual and Instrument Meteorological Conditions are the weather minima defined by visibility and distance from cloud. Operating in IMC requires an instrument rating and an IFR clearance.

Visual Flight Rules allow navigation and separation by outside visual reference, subject to minimum visibility and cloud clearance. The pilot remains responsible for traffic avoidance.

Instrument Flight Rules permit flight in cloud using cockpit instruments, with separation provided by air traffic control and procedures based on radio navigation aids.

A shortage of oxygen reaching body tissues, causing impaired judgement, euphoria and loss of colour vision. It is insidious because the affected pilot often fails to notice the symptoms.

Abnormally rapid or deep breathing that washes out carbon dioxide, producing dizziness, tingling and cramps. Its signs resemble hypoxia but it improves with slower, controlled breathing.

The period after loss of oxygen supply during which a person can still take deliberate corrective action before becoming incapacitated.

A false perception of aircraft attitude or motion arising when the inner ear misinterprets acceleration in the absence of visual reference. Recovery depends on trusting the instruments.

A false sensation of pitching up during strong linear acceleration, such as a take-off roll, which can prompt an inappropriate nose-down control input if the pilot has no visual reference.

The inner-ear organs that sense rotation and linear acceleration. They cannot distinguish gravity from acceleration in sustained motion, making them a major source of disorienting illusions.

The plumbing that supplies ram air pressure from the pitot tube and static pressure from the static ports to the airspeed indicator, altimeter and vertical speed indicator.

A blockage of the pitot head that traps pressure and makes the airspeed indicator behave like an altimeter, over-reading in a climb and under-reading in a descent.

The instrument that compares pitot ram pressure with static pressure to display indicated airspeed, with coloured arcs marking stall, flap and never-exceed limits.

A ground beacon that transmits a signal allowing the receiver to determine the aircraft's magnetic bearing from the station, called the radial, for navigation and airway tracking.

The magnetic bearing of a line extending outward from a VOR station, measured clockwise from magnetic north. Flying inbound on a radial means tracking toward the station.

A non-directional beacon transmits a low-frequency signal that an automatic direction finder senses to show the relative bearing of the station, used for homing and holding.

A discontinued approach in which the crew applies take-off power, climbs and follows the published missed approach procedure to rejoin the traffic pattern or a new clearance.

The minimum height on a precision approach at which a missed approach must be initiated if the required visual reference has not been established.

A published sequence of turns, climbs and holding designed to keep an aircraft clear of obstacles when an approach cannot be completed.

The mandatory repetition of a controller's clearance, instruction or runway assignment by the pilot, allowing the controller to detect and correct any misunderstanding.

The four-digit octal code selected on the transponder that identifies the aircraft to air traffic control radar and links it to the flight plan.