Canada IATRA key terms

The speed by which a takeoff must be continued if an engine fails, because stopping within the remaining runway is no longer assured. Below it, a failure calls for aborting.

The minimum speed to be maintained with one engine inoperative after rotation, giving adequate climb gradient and control. It is held until obstacles are cleared or acceleration begins.

The runway length needed to accelerate to V1, lose an engine, and bring the aeroplane to a full stop using brakes and, where fitted, reverse thrust and spoilers.

The runway length at which the accelerate-stop distance equals the one-engine-inoperative takeoff distance, so neither aborting nor continuing is penalised. It varies with weight, altitude and temperature.

The height gained per unit of horizontal distance with one engine inoperative, expressed as a percentage. Required values differ for takeoff, en-route and approach configurations.

Pressure altitude corrected for temperature deviation from standard. High values reduce engine power, propeller thrust and wing lift, lengthening takeoff runs and flattening climb performance.

The altitude indicated when the altimeter subscale is set to the standard datum of 29.92 inches of mercury or 1013.2 hectopascals. It is the basis for flight levels and performance charts.

The maximum density altitude at which an aeroplane can climb at a specified low rate, commonly 100 feet per minute. It marks the practical upper limit for steady flight.

A descent profile flown after an engine failure at altitude, trading height for distance so the aeroplane can reach a suitable aerodrome or clear terrain along the route.

On a conventional twin, the engine whose failure produces the greatest adverse yaw and control difficulty, usually the one whose propeller slipstream acts least favourably on the tail.

The lowest speed at which the aeroplane remains controllable with the critical engine failed and the other at takeoff power, using no more than a defined rudder force.

The yawing and rolling moment produced when one engine develops more thrust than the other. It must be countered with rudder and aileron, and increases as speed decreases.

Turning the blades of a failed engine's propeller edge-on to the relative airflow, minimising drag and vibration. It reduces the asymmetric drag that otherwise dominates single-engine performance.

A propeller allowed to rotate freely in the airflow after an engine failure or shutdown. It creates significant drag compared with a feathered blade and should be stopped where practical.

Protection against airframe ice. Anti-icing prevents accumulation, for example with heated leading edges or fluid; de-icing removes ice already formed, such as by inflatable boots.

Ice forming in the carburettor throat as fuel vaporises and pressure drops, restricting airflow and causing rough running or power loss. It can occur at above-freezing outside temperatures.

Ice that accumulates on an aeroplane during a hold in cloud at temperatures near or below freezing, often at a rapid rate because the aircraft remains in the same icing layer.

Supercooled water droplets that remain liquid below zero and freeze on impact with an airframe. It produces rapid, severe ice accretion and is a strong reason to divert or turn back.

A rapid change in wind speed or direction over a short distance near the ground, often near fronts, thunderstorms or inversions. It can cause sudden airspeed and glidepath excursions on approach.

A small, intense downdraft spreading out at the surface, typically from a thunderstorm. It can produce headwind-to-tailwind reversals that cause severe performance loss close to the ground.

A discontinued approach or landing, flown by applying power, establishing climb and following the published missed approach. It is a normal manoeuvre and should be briefed before every approach.

A published sequence of turns, climbs and altitude limits to be flown if an approach cannot be completed. It protects obstacle clearance and ends at a holding fix or point for re-approach.

The height above a reference datum, usually touchdown zone elevation, at which a missed approach must be initiated if the required visual reference is not established on a precision approach.

The lowest altitude permitted on a non-precision approach before the required visual reference is in sight and descent to land may continue. It is not a limit below which descent is automatically allowed.

A Canadian rule prohibiting approaches below specified minima when reported weather is worse than the values for the approach and runway. It applies even if the pilot sees the runway.

The altitude at or below which altimeters are set to local pressure and above which the standard setting is used. Canada uses a fixed transition altitude of 18,000 feet.

An altitude expressed in hundreds of feet with the altimeter set to the standard datum, used above the transition altitude. It ensures all aircraft share a common pressure reference.

Airspace of defined dimensions within which air traffic control service is provided and in which certain pilots require clearances. Classes and dimensions are shown on aeronautical charts.

Designated Canadian airspace in which aircraft must carry and operate a serviceable transponder, generally at or above specified altitudes and around major airports.

The visibility and distance-from-cloud limits that must be met to fly under visual flight rules in a given class of airspace. They vary with airspace and altitude.

A clearance allowing flight under visual flight rules in controlled airspace when weather is below normal VFR minima, subject to pilot request, controller approval and specified ground visibility limits.

The final authority and accountability for the operation and safety of the aircraft rests with the pilot-in-command, regardless of clearances, instructions or the presence of other crew.

Repeating back an air traffic control clearance or instruction in full to allow the controller to detect errors. Items such as altitudes, headings, routes and frequencies must be read back.

Training and practice in using all available resources, including crew, automation and information, to manage workload, communication and decision-making. It targets human error and authority gradients.

A continuing accurate picture of what the aircraft, crew and environment are doing and what is likely next. Losing it is a common precursor to navigation and fuel-management errors.

An accident in which a serviceable aircraft is flown into terrain or water, usually through loss of situational awareness, distraction or an undetected descent. Terrain warnings and disciplined monitoring reduce risk.

The lowest altitude permitting safe flight over built-up areas or terrain, with a margin for emergency landing. It is a regulatory minimum, not a substitute for obstacle and terrain planning.