ATPL Performance (EASA) key terms

The total runway length needed from the start of the take-off roll to the point where the aircraft reaches 35 ft above the runway surface, including the distance used to accelerate to V1 and complete the failure case.

The declared length of the runway plus any clearway, measured from the start of the take-off run, within which an aircraft can complete a take-off and reach the required screen height.

The declared length of runway available and suitable for the ground run of an aircraft during take-off, excluding any clearway or stopway additions.

A defined area beyond the runway end, free of obstacles and under the control of the aerodrome operator, over which an aircraft may climb after lift-off; it counts toward TODA but not TORA.

A defined rectangular area beyond the runway end, prepared and suitable for an aircraft to stop on during a rejected take-off, usable to increase the accelerate-stop distance available.

The runway length plus any stopway, declared as the distance within which an aircraft can accelerate to V1 and then bring the aircraft to a full stop after an engine failure.

The runway length at which the accelerate-stop distance equals the take-off distance required with one engine failed at V1, giving the shortest field from which both cases can be satisfied.

The decision speed at which, following an engine failure, the pilot can either continue the take-off or reject it and stop within the remaining runway; it is chosen so both outcomes are possible.

The rotation speed at which the pilot applies back-stick to raise the nose and lift off; it is scheduled so the aircraft reaches V2 by 35 ft with an engine failed.

The take-off safety speed that must be maintained to 35 ft with one engine inoperative; it guarantees minimum control and climb gradient in the second segment.

The minimum control speed on the ground, the lowest speed at which the aircraft can be kept straight on the runway using rudder alone after a sudden engine failure during the take-off run.

The minimum control speed in the air, the lowest speed at which the aircraft remains controllable with one engine failed and the other at take-off power, with a maximum rudder force of 150 lb.

The height above the take-off surface, normally 35 ft for jet aircraft, at which the take-off flight path is considered to begin for obstacle clearance and performance scheduling.

The net flight path, starting at 35 ft at V2 with one engine failed, that the aircraft must be able to follow while clearing all obstacles by the required margin.

The actual one-engine-inoperative flight path reduced by a specified gradient decrement (0.8% for two-engine aircraft), giving the path that must clear obstacles.

The minimum vertical or gradient separation that the net take-off flight path must maintain above obstacles in the take-off area, typically 35 ft vertically or a specified gradient.

A temperature higher than the actual outside air temperature, entered by the crew to reduce thrust and lengthen engine life, provided the resulting performance still meets all take-off requirements.

A reduced take-off thrust setting, lower than the maximum certified take-off thrust but higher than a flex reduction, selected to extend engine life while preserving adequate performance.

The required one-engine-inoperative climb gradient from 35 ft to 400 ft with take-off flaps and gear retracted, typically 2.4% for two-engine aircraft.

The one-engine-inoperative climb gradient required from 35 ft to 400 ft with take-off flaps and landing gear still extended, typically 0.0% for two-engine aircraft.

The ratio of vertical height gained to horizontal distance travelled, expressed as a percentage; it determines obstacle clearance and is affected by weight, temperature, altitude and configuration.

The vertical speed of the aircraft, usually expressed in feet per minute, obtained from the excess of thrust over drag multiplied by true airspeed.

The pressure altitude at which the maximum rate of climb falls to 100 ft per minute in the clean configuration at maximum continuous thrust.

The pressure altitude at which the maximum rate of climb becomes zero, so the aircraft can no longer climb in the clean configuration at maximum continuous thrust.

The descent profile flown after an engine failure in cruise, calculated so the aircraft reaches a suitable alternate aerodrome while clearing terrain along the route.

The highest pressure altitude at which the aircraft can maintain level flight, or a specified climb gradient, with one engine inoperative at maximum continuous thrust.

The highest thrust setting certified for use without a time limit, used for engine-out cruise and for climb after the take-off segments are complete.

The distance flown per unit of fuel consumed, usually nautical miles per kilogram or per pound; it peaks at a particular speed and altitude for a given weight.

A speed, typically about 1.02 times the speed for maximum specific range, chosen to give near-optimal fuel mileage while retaining a small margin for scheduling.

A number entered into the flight management system that trades fuel cost against time cost, determining the economic cruise speed and climb/descent speeds.

A planned increase in cruise altitude as fuel is burned and weight falls, allowing the aircraft to remain near its optimum altitude and reduce fuel consumption.

The cruise altitude at which, for a given weight and speed, the aircraft achieves its maximum specific range, balancing induced and parasite drag.

The runway distance needed from crossing the threshold at 50 ft to a full stop, factored by 1.67 for dry runways to give the scheduled landing distance.

The declared length of runway available and suitable for the landing ground run, measured from the threshold to the runway end, excluding any displaced threshold area.

The actual demonstrated landing distance multiplied by a safety factor (1.67 dry, 1.92 wet) to give the distance that must not exceed the LDA.

A threshold located at a point other than the physical runway end, reducing the LDA while the runway length beyond it may still be used for take-off and taxiing.

The target speed at the 50 ft screen height, normally 1.3 times the stall speed in the landing configuration, adjusted for wind and gust to the landing distance.

A runway covered by standing water, slush, loose snow or ice beyond specified depths, which increases landing distance and may require the higher 1.92 wet factor.