CAA NZ ATPL Theory - Flight Planning key terms

The highest mass at which the aircraft is certified for the start of the take-off run, fixed by the manufacturer and stated in the flight manual. It limits structural and performance loads regardless of actual conditions.

The greatest mass at which the aircraft may touch down, set by structural certification limits. A flight must plan to burn or jettison fuel so that landing mass does not exceed this value.

The maximum mass permitted with usable fuel excluded, protecting the wing root structure from bending loads. It caps payload plus unusable fuel and operating items before fuel is added.

The aircraft mass including crew, crew baggage, catering, potable water and other operational items, but excluding traffic load and usable fuel. It is the baseline from which all load calculations begin.

Dry operating mass plus take-off fuel. It represents the mass of the aircraft at departure with fuel but without revenue payload, and is used as an intermediate step in load sheets.

The total mass of passengers, baggage and cargo carried, including any non-revenue load. It is added to dry operating mass to give zero-fuel mass for the flight.

The take-off mass actually used for performance calculation, being the lowest of the field-length-limited, climb-limited, obstacle-limited and structural limits. It may be below MTOM when conditions are restrictive.

The highest take-off mass at which the accelerate-stop and take-off distances fit the available runway, clearway and stopway for the reported conditions. It varies with runway surface, slope, wind and temperature.

The runway length at which the accelerate-stop distance equals the take-off distance to 35 feet with one engine inoperative. It identifies the V1 that gives the shortest field requirement.

The speed at which a rejected take-off may still be stopped within the accelerate-stop distance, or a continued take-off achieved within the take-off distance. It is selected before take-off and drives brake energy and obstacle clearance.

The distance from brake release to a full stop after failure of the critical engine at V1, plus a short crew reaction allowance. It is compared with the available accelerate-stop distance during dispatch.

A defined area beyond the runway end, free of obstacles and under control of the aerodrome authority, that may be included in take-off distance calculations. It must be at least 75 metres wide and have limited slope.

A prepared rectangular area beyond the runway end, able to support the aircraft without structural damage, usable for deceleration after a rejected take-off. Its length is added to the runway to give accelerate-stop distance available.

The runway length plus any clearway, declared by the aerodrome operator, within which the aircraft must reach 35 feet with the critical engine failed. It appears on the aerodrome chart and in performance software.

The runway length plus any stopway, declared for use in a rejected take-off. It is the limiting declared distance when stopways are provided and must be compared with the calculated accelerate-stop distance.

The length of runway declared available and suitable for the ground run of a landing aeroplane, measured from the threshold. Displaced thresholds reduce LDA even though the paved surface may extend further.

The landing mass used for dispatch, being the lowest of the structural MLM and the mass permitted by landing distance and missed-approach climb requirements at the destination or alternate. It may force fuel or payload reduction.

The one-engine-inoperative climb gradient that must be achievable in the landing configuration at the destination. If the aeroplane cannot meet it at the planned mass, landing mass must be reduced before dispatch.

A threshold located at a point on the runway other than the physical beginning, usually to provide obstacle clearance on approach. The paved area before it is not usable for landing but may be used for take-off.

A runway covered by standing water, slush, loose snow or wet ice beyond defined depths, reducing friction and braking action. Performance data for contaminated surfaces must be used, often with large mass penalties.

The minimum fuel required by the operator's approved fuel policy for a flight, comprising taxi, trip, contingency, alternate, final reserve and additional fuel. It must be on board before departure and is documented on the operational flight plan.

The fuel needed from take-off to touchdown at the destination, including climb, cruise, descent and approach for the planned route and forecast conditions. It is recalculated whenever the route or winds change significantly.

Fuel carried to cover unforeseen factors such as deviations from forecast winds, routing or cruise level. It is normally a percentage of trip fuel or a time-based amount, and may be reduced under approved procedures.

Fuel that must remain on board on arrival at the destination alternate, intended for holding. For turbine aeroplanes it is typically 30 minutes at holding speed at 1,500 feet above the alternate.

Fuel required to fly from the destination to the destination alternate, including approach and landing, based on forecast conditions. It is not required when no alternate is needed under the applicable rules.

Additional fuel required when the destination has no usable alternate, allowing the aircraft to hold and then fly to a suitable diversion aerodrome. It is added to the normal policy fuel for such destinations.

A method where the flight carries enough fuel to reach a decision point, then either continues to the destination or diverts, with the fuel plan updated in flight. It allows reduced contingency fuel when approved and monitored.

The position along the route from which it is no longer possible to return to the departure aerodrome with the fuel remaining. It depends on wind, fuel flow and reserve requirements and is calculated before flight.

The point on a route where the time to fly to either of two diversion aerodromes is equal, given the winds in each direction. It is used to plan diversion fuel for remote or oceanic sectors.

The distance flown per unit of fuel, usually nautical air miles per kilogram or per pound. It is highest at the optimum cruise altitude and speed and is used to compare cruise techniques and monitor fuel efficiency.

A cruise speed slightly above maximum range speed, giving about 99 percent of best specific range while reducing flight time. It is used when fuel economy matters but a very slow cruise is unacceptable.

A number entered into the flight management computer that trades fuel cost against time cost to select cruise speed. A low value favours economy, a high value favours speed and schedule.

A planned increase in cruise level as fuel is burned and the aircraft becomes lighter, allowing a higher optimum altitude. It improves specific range on long sectors and must be coordinated with air traffic control.

The cruise level at which the aircraft achieves its best specific range for the current mass and temperature. It rises as mass decreases and usually falls in warmer than standard conditions.

An aerodrome to which a flight may proceed if landing at the destination is not possible, and for which fuel is carried. It must meet weather and runway requirements at the estimated time of use.

The document prepared by the operator for a specific flight, showing route, masses, fuel figures, times and alternates. It is signed by the commander and forms the basis for fuel and performance decisions.

The message filed with air traffic services giving aircraft identification, route, level, speed and estimated times so that control and search and rescue can be provided. It must be filed before departure and updated when the plan changes.

A specified geographical location used to define a route or part of a flight, such as a waypoint, navaid or intersection. It must be identifiable and, where required, named in the ATS flight plan route field.

The coded identifier for a published air traffic services route, such as A, B, G, R or L series, showing its type and direction. It is entered in the route field of the flight plan to describe the intended path.

The initial direction of the shortest path between two points on the Earth's surface, measured at the departure point. On long sectors the track changes continuously and must be recalculated along the route.

A track that crosses all meridians at the same angle, appearing as a straight line on a Mercator chart. It is constant but not the shortest path, and is used for short sectors and chart plotting.

The difference between the actual temperature at a level and the International Standard Atmosphere value for that level. Positive deviations increase density altitude and reduce performance, so they must be applied in take-off and cruise calculations.

Pressure altitude corrected for temperature, representing the altitude the aircraft performance feels. High density altitude lengthens take-off and reduces climb, and is used to enter performance charts.

The headwind or tailwind resolved along the intended track, used to adjust groundspeed, fuel burn and time. It is derived from forecast winds aloft and must be updated with actual winds in flight.

A forecast chart showing fronts, jet streams, turbulence, icing and cumulonimbus areas relevant to a flight level band. It is used in route planning to avoid hazardous weather and estimate fuel effects.

The boundary between the troposphere and stratosphere where temperature stops falling with height. Its height affects jet stream location, turbulence and the cruise levels chosen for long sectors.

The certified forward and aft limits of centre of gravity for each mass, within which the aircraft must remain throughout the flight. Loading outside it can affect control, trim and performance.

A scaled number used to express the moment of an item about a reference point, allowing easy addition and conversion to centre of gravity. Load sheets use indices to keep the arithmetic simple.

The document showing the distribution of mass, the resulting centre of gravity and the final masses for the flight. It is checked and signed before departure and must agree with the operational flight plan.