JCAA CPL Theory Exam key terms

A set of rules under which a pilot operates an aircraft primarily by looking outside for traffic and terrain, only permitted when weather meets specified minimum visibility and cloud-clearance criteria.

Rules governing flight in which navigation and traffic separation depend on cockpit instruments and instructions from air traffic control, allowing operation in weather below VFR minima.

An authorization issued by an air traffic controller for an aircraft to proceed under specified conditions, which the pilot must read back and comply with unless an emergency requires deviation.

Weather conditions expressed in terms of visibility and distance from cloud that meet or exceed the minimum values prescribed for flight under visual flight rules in a given airspace.

Weather conditions below the prescribed visibility and cloud-clearance minima for visual flight, requiring an instrument rating and an IFR clearance to operate legally.

The acute angle between the wing chord line and the relative airflow approaching it; increasing this angle raises lift until the critical angle is exceeded and the wing stalls.

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

Drag created as a by-product of lift, caused by spanwise airflow generating wingtip vortices; it increases with angle of attack and is greatest at low airspeed and high weight.

The ratio of total lift produced to the aircraft's weight, expressed in g units; it rises in turns and manoeuvres and directly raises the speed at which the wing stalls.

The lowest indicated airspeed at which an aircraft can maintain level flight before exceeding its critical angle of attack; it increases with weight, load factor and aft centre of gravity.

The point through which the total weight of the aircraft acts; its position must stay within a certified forward and aft range for controllability, performance and stall behaviour to remain acceptable.

The calculation of aircraft mass and the location of its centre of gravity, ensuring both stay within certified limits for the planned flight, including fuel, payload and baggage.

The highest mass at which an aircraft is certified to begin the take-off run, limited by structural strength, climb performance and obstacle-clearance requirements for the planned conditions.

Pressure altitude corrected for non-standard temperature; high density altitude reduces engine power, propeller thrust and lift, lengthening take-off runs and lowering climb performance.

The altitude indicated when the altimeter subscale is set to the standard pressure of 1013.25 hPa, used for flight levels and for computing aircraft performance.

The pressure value set on an altimeter so that it reads elevation above mean sea level at the ground; used below the transition altitude to keep altitude references consistent with terrain.

The altitude above which a pilot changes the altimeter reference from local pressure to standard pressure and reports height in flight levels rather than altitude.

A surface of constant atmospheric pressure referenced to standard pressure 1013.25 hPa and expressed in hundreds of feet, used for separation of aircraft above the transition altitude.

The direction of the air approaching the aircraft as seen from the aircraft, opposite to the flight path; its angle to the chord line defines the angle of attack.

The tendency of an aircraft to yaw away from the direction of a roll, caused by the descending aileron producing more induced drag than the rising one; corrected with coordinated rudder.

The angle between the aircraft's lateral axis and the horizontal; increasing bank increases load factor and stall speed and reduces the vertical component of lift available.

A condition in which body tissues receive insufficient oxygen, causing impaired judgement, euphoria and loss of consciousness; it can occur without warning at altitude in unpressurised aircraft.

The period after loss of oxygen supply during which a person can still perform useful, deliberate actions before becoming incapacitated, shortening rapidly as altitude increases.

Abnormally rapid or deep breathing that lowers blood carbon dioxide, producing dizziness, tingling and confusion whose symptoms resemble hypoxia but which improves with slower, controlled breathing.

A false perception of the aircraft's attitude or motion caused by misleading vestibular and visual cues in the absence of a clear horizon, often leading to loss of control in instrument conditions.

The leading edge of an advancing cold air mass that undercuts warm air, producing rapid lifting, cumuliform cloud, showers and often gusty surface winds with a sharp temperature drop.

The boundary where advancing warm air rides over colder air, giving a gradual slope, layered stratiform cloud, widespread steady precipitation and a slow fall in pressure.

A towering convective cloud reaching the tropopause, associated with thunderstorms, severe turbulence, icing, hail and strong vertical currents, which pilots must avoid by a wide margin.

Ice forming in the carburettor venturi from fuel vaporisation and pressure drop, most likely at temperatures between about -7 and +21 degrees Celsius with high humidity, causing power loss.

The aircraft system supplying ram air pressure from the pitot tube and static pressure from static ports to the airspeed indicator, altimeter and vertical speed indicator.

An obstruction of the pitot head, often by ice or insects, that traps pressure in the system; the airspeed indicator then behaves like an altimeter, over-reading in climb and under-reading in descent.

The angular difference at a given place between true north and magnetic north, applied when converting between true and magnetic bearings on charts and in navigation calculations.

The error of a magnetic compass caused by the aircraft's own magnetic fields, varying with heading and recorded on a compass correction card used to convert heading to compass heading.

The direction in which the aircraft's longitudinal axis points, expressed in degrees from north; it differs from track because of drift caused by wind.

A ground-based service that determines the bearing of an aircraft's radio transmission and can give the pilot a magnetic heading, a QDM, or a position fix.

A magnetic bearing from a VOR station, displayed by the aircraft's receiver; flying a selected radial provides a defined track to or from the beacon.

The pilot's repetition of a controller's safety-related instruction or clearance to confirm it was received and understood correctly; failure to read back requires the controller to repeat it.

The international radiotelephony distress signal, spoken three times, used only when an aircraft is threatened by serious or imminent danger and requires immediate assistance.

The international radiotelephony urgency signal, spoken three times, used when a situation is concerning but does not yet require immediate assistance, such as a non-critical technical problem.