Advance Crew Rest
A scheduled rest period before or during a flight, provided to designated crew members to meet fatigue management or regulatory requirements for ultra-long operations.
View termCategories
Long Haul
Browse Long Haul terms for pilots, air traffic controllers, cabin crew and aviation learners.
Languages
Aft Centre Tank
A fuel tank located in the rear centre section of the aircraft fuselage, used for fuel storage and distribution during long-haul operations.
View termAlternate Diversion Field
An airport selected in the flight plan to which an aircraft may proceed when landing at the destination becomes inadvisable.
View termAlternate Threshold Fuel
The predetermined minimum fuel required at an alternate airport's landing threshold, ensuring safe diversion in case a landing at the intended destination is not possible.
View termAutomatic Position Report
A position report transmitted automatically by onboard avionics via datalink (CPDLC or ADS-C) at predetermined waypoints or intervals, requiring no crew action.
View termAutomatic Step Climb
A flight mode or FMS function that automatically commands step climbs as aircraft weight decreases to optimize fuel efficiency and performance.
View termBiological Clock
The natural internal time-keeping system that regulates physiological activities, directly affecting crew alertness and fatigue during time zone changes and long-haul operations.
View termBrake Energy Limit
The maximum energy that aircraft brakes can safely absorb during landing or rejected takeoff, determined by aircraft weight, speed, and system design, to prevent brake failure or fire.
View termBunk Rest Period
A scheduled period during a flight in which a crew member is off duty and resting in a designated bunk or crew rest facility.
View termCenter Gravity Management
The active process of monitoring and controlling the aircraft’s center of gravity throughout all flight phases to ensure safe and efficient operation within prescribed limits.
View termCircadian Offset
The difference between local time and a crew member's biological night, often considered in fatigue management and long-haul flight scheduling.
View termClass One Navigation
Navigation in airspace where the position of the aircraft can be continuously determined by reference to ground-based radio navigation aids.
View termClass Two Navigation
Navigation in airspace where position cannot be reliably fixed using ground-based radio navigation aids, requiring the use of long-range navigation systems.
View termClear Air Turbulence
Turbulence that occurs in clear air, typically at high altitudes, away from thunderstorms and not associated with visible clouds, often found near jet streams or frontal zones.
View termContingency Procedure
A predetermined sequence of actions to be followed when an abnormal or emergency situation occurs during flight, as defined in company or ICAO procedures.
View termController Pilot Link
A data communication system (CPDLC) used for direct exchange of messages between air traffic controllers and pilots, especially in oceanic and remote airspace.
View termCrew Augmentation
The practice of adding qualified crew members to the flight crew to allow in-flight rest and ensure regulatory compliance on long-haul or ultra-long-haul flights.
View termCritical Fuel State
A situation where an aircraft's fuel supply has reached a level where it can only proceed to the intended destination and no further delay can be accepted.
View termData Link Connection
A digital communications channel established between aircraft and ATC/dispatch for automatic reporting, clearances, and text exchanges (e.g., CPDLC, ACARS).
View termDecision Fuel Point
A predetermined point along the route where a decision is made to proceed to the destination or divert based on remaining fuel and current conditions.
View termDependent Surveillance Contract
A prearranged automatic reporting agreement (ADS-C) between ATC and aircraft for position, intent, and status data in remote or oceanic airspace.
View termDiversion Fuel
The amount of fuel required to divert from planned destination to an alternate aerodrome, factoring weather, distance, and required reserves.
View termDrift Down Procedure
A contingency descent profile followed after an engine failure at cruise altitude to achieve the aircraft’s new single-engine ceiling while maintaining obstacle clearance.
View termEmergency Descent Path
A predetermined safe vertical and lateral route for rapid descent to a lower altitude in the event of depressurization or other emergencies.
View termEngine Inoperative Drift
The lateral displacement from track or altitude lost when an aircraft operates with one or more engines inoperative, especially during ETOPS segments.
View termEntry Transition Point
The designated waypoint where an aircraft changes from domestic to oceanic or remote-airspace procedures and communications.
View termEqual Fuel Point
A point along the route where the fuel required to return to the departure airport equals the fuel required to continue to the destination, used in diversion and contingency planning.
View termEqual Time Chart
A chart used in flight planning to determine the point at which the flight time to two alternate aerodromes is equal, commonly applied for ETOPS and long-range operations.
View termEqual Time Point
The geographic point along a route at which the flying time to two selected diversion aerodromes is equal, used for contingency decision-making.
View termEquatorial Route
A specific flight route crossing or lying close to the equator, designed for optimal navigation in equatorial regions.
View termEscape Fuel Planning
Calculation of the minimum fuel required to depart from an area with operational hazards to a safe location.
View termEscape Route Planning
The advance definition of contingency flight paths from the main track to a safe diversion airport in case of in-flight emergencies over remote areas.
View termExtended Overwater
Flight operation segment that takes place beyond a specified distance from land, requiring special equipment and regulatory compliance (ETOPS/EDTO rules).
View termExtended Range Limitation
A regulatory or operational constraint that restricts the maximum allowable distance or duration for extended range operations, typically ETOPS or EDTO.
View termExtended Range Operations
Flight by any aircraft on routes that place it at a distance from a suitable airport greater than the authorized threshold, encompassing ETOPS and other regulatory provisions (EROPS).
View termExtended Twin Operations
Operation of twin-engine aircraft on routes where a diversion airport may be more than 60 minutes away at one-engine inoperative cruise speed, subject to special performance and dispatch requirements (ETOPS).
View termFatigue Risk Management
A systematic process, approved by authorities, to manage crew fatigue using scheduling, monitoring, and mitigation strategies for safe operations.
View termFlight Redispatch
The in-flight process whereby operational control re-evaluates conditions and issues a new release for the remainder of the flight.
View termFuel Imbalance Control
Actions taken to monitor and correct uneven fuel distribution between tanks to maintain safe balance and aircraft handling.
View termFuel Tanker Flight
A flight carrying more fuel than required, often to avoid higher fuel costs at destination or for operational contingencies.
View termFuel Temperature Limit
The minimum or maximum allowable temperature for fuel in aircraft tanks or lines to prevent fuel waxing or freezing, especially during high-altitude operations.
View termFuel Transfer
The movement of fuel between tanks to ensure aircraft balance and supply during various flight phases.
View termHigh Frequency Calling
The use of HF radio to establish long-distance communications with ATC, commonly required in remote or oceanic airspace.
View termHigh Latitude Navigation
Navigation procedures and technologies required for flights operating in polar or near-polar regions, often above 78° latitude.
View termHydraulic Pressure Loss
A reduction or complete loss of hydraulic system pressure, potentially affecting flight control surfaces, landing gear, and braking systems; requires immediate crew action.
View termIce Crystal Icing
A form of high-altitude icing caused by ingestion of ice crystals into engines, potentially resulting in engine flameout or damage.
View termInflight Replanning
Modification of the flight plan while airborne, in response to operational, weather, or airspace constraints.
View termIsland Alternate
An aerodrome located on an island and designated as an alternate for oceanic or remote area operations.
View termJet Stream Core
The center of maximum wind velocity within a jet stream, critical for optimizing flight path, fuel efficiency, and turbulence avoidance.
View termLanding Alternate
An aerodrome specified in the flight plan to which a flight may proceed when a landing at the intended destination becomes inadvisable.
View termLong Range Cruise
A cruise speed selected for maximum range per unit of fuel on long-haul flights, balancing fuel efficiency and time.
View termManual Position Report
A position report provided by a flight crew via voice or datalink, specifying current aircraft location, when automatic position reporting is not available or not required.
View termMontevideo Alternate
Carrasco International (SUMU/Montevideo), designated as the alternate aerodrome for flights operating to/from South Atlantic, per contingency or ETOPS requirements.
View termNorth Atlantic Track
A designated system of daily updated routes for transatlantic flights between Europe and North America, coordinated and published by oceanic ATC agencies.
View termNorth Pacific Track
A designated organized track system for flight operations across the North Pacific between North America and Asia, updated daily by ATC.
View termOceanic Clearance
ATC authorization required for entry into and flight within oceanic airspace, specifying route, level, and Mach number.
View termOceanic Entry Point
The specific waypoint where an aircraft transitions from domestic to oceanic airspace, usually involving a procedural clearance.
View termOil Temperature Margin
The difference between actual engine oil temperature and the maximum safe operating limit, ensuring safe operation and indicating potential issues if margin decreases.
View termOperating Minimums
The lowest meteorological and operational conditions under which an aircraft may be operated, as published by regulatory authorities for each phase of flight.
View termOptimum Altitude
The flight level or altitude that offers the best balance between fuel consumption, aircraft performance, and weather conditions.
View termPolar Air Route
A designated transcontinental flight path passing over the polar regions, generally used for efficient intercontinental operations between North America, Europe, and Asia.
View termPolar Diversion Site
A pre-designated airport suitable for emergency landing or diversion by polar-route aircraft, equipped and authorized for extended operations in polar regions.
View termRedispatch Clearance
Official authorization given at a predetermined point, permitting continuation to the planned destination or re-clearance to an alternate based on current operational factors.
View termRedispatch Point
A designated waypoint or position along the route after which flight dispatch is revalidated or amended based on updated operational or weather conditions.
View termRedispatch Release
A flight release authorizing a change of destination or continuation beyond a point after departure, subject to operational conditions or weather.
View termRequired Navigation Ten
A navigation specification requiring aircraft to maintain a track-keeping accuracy of ±10 nautical miles for at least 95% of the flight time within designated airspace, commonly referred to as RNP 10.
View termRescue Coordination Center
A designated center responsible for organizing and coordinating search and rescue operations in a specified area, as defined in ICAO Annex 12.
View termRoute Reclearance
An amended ATC clearance that modifies the previously cleared route, typically issued to avoid weather, airspace restrictions, or traffic.
View termRoute Track Message
An ATC message providing route, track, or clearance information, typically via data link, for flights in procedural airspace.
View termStep Climb Profile
A flight profile in which an aircraft increases cruise flight level in stages as weight decreases and conditions permit, to optimize fuel efficiency.
View termTankering Decision
The operational determination to carry extra fuel for economic or logistical reasons, usually based on fuel pricing and availability at destination.
View termTrim Fuel Tank
A specialized fuel tank located in the horizontal stabilizer or tail, used to optimize aircraft balance and fuel management.
View termTropical Air Route
An airway or designated flight route that traverses tropical climate regions, often with unique meteorological and navigational considerations.
View termTropopause Height
The altitude at which the troposphere ends and the stratosphere begins, critical for flight planning due to temperature and wind variations.
View termTurbulence Procedure
A set of prescribed actions for flight crew to follow when encountering turbulence, including changes in altitude, speed, and securing the cabin.
View termUltra Long Haul
A non-stop flight covering an exceptionally long distance, typically over 16 hours or more than 7,000 nautical miles, requiring special crew and operational procedures.
View termVolcanic Ash Route
A temporary route planned to avoid areas of volcanic ash, based on current volcanic activity and advisories.
View termWaypoint Position Report
A mandatory ATC report specifying aircraft position, time, flight level, and estimates for the next waypoint, typically required over oceanic or remote routes.
View termWeather Avoidance
Flight planning or tactical maneuvering to avoid hazardous weather areas using deviation, rerouting, or altitude changes.
View termWeather Drift
Deviation from planned track or route due to wind or meteorological factors, often requiring heading or routing adjustments.
View term