Commercial Pilot Licence Aeroplane (CPAER) key terms

Canada's federal aviation rules covering aircraft operation, licensing, airworthiness, airspace and flight procedures. Pilots must comply with the parts applicable to their licence, aircraft and type of operation.

The pilot who has final authority for the operation and safety of the aircraft during flight. The PIC is responsible for regulatory compliance, the safety of persons on board and the conduct of the flight.

Controlled airspace extending upward from the surface around a controlled aerodrome to a specified altitude. Aircraft normally need an air traffic control clearance, or a specified radio contact, to enter.

A designated radio frequency used at certain uncontrolled aerodromes. Pilots must broadcast specified position reports and maintain a listening watch, as required by the Canadian Aviation Regulations.

An authorization permitting flight under visual flight rules inside a control zone when weather is below normal VFR minima. It requires an ATC clearance and compliance with stated visibility and cloud-clearance limits.

The minimum flight visibility and cloud-clearance distances required for visual flight. The values depend on the class of airspace and altitude, and are set out in the regulations.

A notice containing time-critical aeronautical information that is not published in advance, such as closed runways, unserviceable navaids or temporary hazards. Pilots must check NOTAMs during flight planning.

A document confirming that an aircraft conforms to its approved type design and is maintained in accordance with approved procedures. It must be valid for the aircraft to be legally flown.

An aircraft record in which flights, defects and maintenance releases are entered. It provides a continuing history linking the aircraft to its maintenance and airworthiness status.

The speed of an aircraft through the air, corrected for altitude and temperature effects on the airspeed indicator. It is used with wind data to calculate groundspeed and heading.

The direction the aircraft's nose points, measured in degrees from north. It differs from the intended track whenever wind pushes the aircraft sideways.

The actual path of the aircraft over the ground, expressed as a direction in degrees. Wind causes the track to differ from the heading unless a correction is applied.

The angular difference between heading and track, applied to offset drift caused by wind. It is calculated from wind speed and direction relative to the aircraft's true airspeed.

The angular difference between true north and magnetic north at a given location, caused by the Earth's magnetic field. It is applied when converting between true and magnetic directions.

An error in a magnetic compass caused by the aircraft's own magnetic fields and electrical equipment. It is unique to each aircraft and recorded on a deviation card.

A navigation method of calculating position by advancing a known starting point using heading, true airspeed, wind and elapsed time. It must be updated with fixes from visual or electronic sources.

Navigation by observing landmarks and comparing them with a chart to determine position and maintain the intended track. It is often combined with dead reckoning.

The pressure value set on the altimeter subscale so that the instrument indicates altitude above mean sea level at the aerodrome. Setting the correct QNH is essential for terrain clearance.

A theoretical atmosphere with defined sea-level pressure, temperature and lapse rate, used as a reference for aircraft performance and altimetry. Real conditions are compared with it to compute density altitude.

The rate at which temperature decreases with increasing height in the atmosphere. The standard average is about two degrees Celsius per thousand feet in the troposphere.

The temperature to which air must be cooled, at constant pressure and moisture content, for saturation to occur. A small spread between temperature and dew point favours cloud, fog and precipitation.

The height above ground of the lowest broken or overcast cloud layer, or of the vertical visibility into obscuring phenomena. It determines whether VFR flight is legal.

A routine coded observation of actual weather at an aerodrome, including wind, visibility, cloud, temperature, dew point and pressure. Pilots use it to assess current conditions before departure and arrival.

A coded forecast of expected weather at an aerodrome for a stated period, including wind, visibility, cloud and significant changes. It is used for flight planning and alternate selection.

A warning of weather that is potentially hazardous to all aircraft, such as severe turbulence, icing, thunderstorms or volcanic ash. SIGMETs are issued for specified areas and validity periods.

A layer in which temperature increases with height instead of decreasing. Inversions can trap moisture and pollutants below them and are associated with smooth air and reduced visibility.

The accumulation of ice on an aircraft's surfaces when flying through supercooled water droplets. It adds weight, reduces lift and increases drag, and can seriously degrade performance and control.

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

The angle of attack at which airflow separates from the wing and lift drops sharply. A stall can occur at any airspeed or attitude once this angle is exceeded.

The ratio of lift produced to the aircraft's weight, expressed in g units. Increased load factor raises stall speed and structural stress during turns and turbulence.

The point where the aircraft's weight is considered concentrated. Its position affects stability, control effectiveness and performance, and must remain within approved limits.

The altitude in the standard atmosphere at which air density equals the actual density at a given location. High density altitude reduces engine power, propeller thrust and lift, lengthening takeoff runs.

The tendency of an aircraft to yaw away from a turn when ailerons are applied, because the descending wing produces more induced drag. It is countered with coordinated rudder.

The maximum speed at which the aircraft may be operated in any condition. Exceeding it risks structural damage or loss of control, and it is marked by a red line on the airspeed indicator.

The maximum altitude at which an aircraft can maintain a specified rate of climb, commonly 100 feet per minute. Above it, climb performance becomes marginal or impossible.

Disturbed air, mainly wingtip vortices, left behind a moving aircraft. It is most hazardous to light aircraft following heavy transports and is avoided by spacing and flying above the preceding flight path.