Acceleration altitude
The specified altitude after take-off at which an aircraft transitions from take-off power and climb profile to acceleration and flap retraction, as defined in the departure procedure.
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Flight Phase
Browse Flight Phase terms for pilots, air traffic controllers, cabin crew and aviation learners.
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Aerodrome field elevation
The official elevation of an aerodrome above mean sea level, usually measured at the highest point of the landing area.
View termAlternate-airport fuel
The required fuel quantity to fly from the destination airport to a designated alternate airport, including approach and landing at the alternate.
View termAltimeter set
Confirms that the aircraft's altimeter has been adjusted to the correct barometric pressure setting, as assigned by ATC or as required for flight phase.
View termAltimeter setting referenced to mean-sea-level pressure
The altimeter subscale setting so that the instrument indicates altitude above mean sea level. Also known as QNH.
View termAutomatic landing
A landing performed by the aircraft's autopilot system, typically using ILS signals, requiring minimal pilot input, especially under low-visibility conditions.
View termBlock fuel
The total quantity of fuel loaded on board the aircraft before engine start, including fuel for taxi, flight, alternate, holding, and contingency.
View termBlock time
The total elapsed time from when the aircraft first moves under its own power for departure until it finally stops after arrival at the destination gate.
View termClean config
An aircraft configuration in which all lift devices such as flaps and slats are retracted and landing gear is up, optimized for cruise or go-around.
View termCleared ILS approach
ATC clearance instructing an aircraft to conduct an Instrument Landing System (ILS) approach to a specified runway.
View termCleared RNAV approach
ATC clearance authorizing an aircraft to conduct an Area Navigation (RNAV) approach procedure to a specified runway.
View termCleared visual approach
ATC instruction authorizing an aircraft to proceed visually to the airport, maintaining own separation and visual contact with the airport or preceding aircraft.
View termClimb power
A reduced engine power setting selected after take-off and acceleration, used for the climb phase to minimize engine wear while maintaining safe climb performance.
View termClimb via
An ATC instruction to follow published climb restrictions, altitudes, and routes as depicted in a Standard Instrument Departure (SID) procedure.
View termCourse (intended track)
The intended horizontal direction of travel of an aircraft over the ground, usually expressed in degrees from North.
View termCross-check altimeters
Instructs flight crew to independently compare altimeter readings to verify correct setting and altitude indication, ensuring all crew members have matching altimeter values.
View termCross-wind component
The part of the wind velocity that is perpendicular to the runway or the aircraft's track, affecting lateral control during takeoff, landing, or flight.
View termCruise
The phase of flight in which the aircraft maintains a steady flight level and speed along the planned route after climb and before descent.
View termCruise descent
A gradual descent initiated by the pilot or ATC from cruising altitude, often to optimize fuel burn or prepare for arrival, not directly tied to an approach clearance.
View termDrift down
A procedure for descending to a safe altitude following engine failure at cruise. Aircraft descends along a planned path ensuring obstacle clearance and safe flight.
View termEngine start
The action of starting aircraft engines, typically following ATC clearance. Communicated between flight crew and ground control before taxi or pushback.
View termExtra (contingency) fuel
The discretionary amount of fuel carried beyond required minimums to address potential delays, weather, or other unforeseen operational factors.
View termFinal approach
The segment of an instrument approach procedure in which alignment and descent for landing are completed, extending from the final approach fix to the runway.
View termFinal-approach speed
The target airspeed maintained by an aircraft during the last segment of the approach for landing, determined by aircraft type, weight, and configuration.
View termFlaps
Hinged surfaces on the trailing edge of the wing that can be extended to increase lift at lower speeds, used during takeoff and landing.
View termFlare
Landing manoeuvre in which the pilot raises the nose to arrest the descent rate just before touchdown.
View termGear up
A cockpit command for retracting the landing gear, given after a positive rate of climb is established post-takeoff.
View termGlide slope
The vertical guidance portion of an ILS, providing an optimal descent path to the runway threshold for precision approaches.
View termGo-around altitude
The published altitude to which an aircraft must climb when executing a missed approach or go-around procedure.
View termGround speed
The speed of an aircraft relative to the surface of the Earth, as measured by navigation systems.
View termHead-wind component
The part of the wind velocity that blows directly against the direction of travel of the aircraft, improving takeoff and landing performance.
View termHold line
A clearly marked line on the surface of an aerodrome, usually at a runway/taxiway intersection, beyond which an aircraft or vehicle may not proceed unless cleared by ATC.
View termHold pattern
A predetermined maneuver which keeps an aircraft within a specified airspace while awaiting further clearance, typically involving racetrack-shaped circuits about a fix.
View termHolding fuel
The quantity of fuel specifically reserved for holding patterns in case of delays before approach or landing.
View termIdle descent
A descent procedure where engines are set to idle thrust, allowing the aircraft to descend primarily due to gravity, optimizing fuel efficiency and minimizing noise.
View termIdle reverse thrust
Minimum reverse-thrust setting used during rollout to aid deceleration while reducing noise, FOD risk, and brake wear.
View termIndicated airspeed
The airspeed value read directly from the aircraft’s airspeed indicator, not corrected for instrument or atmospheric errors.
View termInitial approach
The segment of an instrument approach procedure between the initial approach fix and the intermediate or final approach fix, preparing for alignment and descent to land.
View termIntermediate fix
A designated point on an instrument approach procedure (IAP) between the initial and final approach fixes, used to define the intermediate segment of the approach.
View termLanding gear down
The position and status indicating the aircraft’s landing gear is fully extended and locked for touchdown and ground operations.
View termLeading-edge device
A movable aerodynamic surface, such as a slat or Krueger flap, installed on the wing’s leading edge and extended to increase lift during takeoff or landing.
View termLine‑up
An ATC instruction for an aircraft to enter the runway and position itself for take-off, without commencing the take-off roll.
View termLocalizer
The horizontal guidance component of the ILS, providing lateral alignment with the runway centerline during instrument approaches.
View termLow-visibility operations
Procedures and requirements for aircraft movements at aerodromes when visibility is reduced below specified minima, including LVP (Low Visibility Procedures).
View termMach number
The ratio of the true airspeed of an aircraft to the speed of sound under the same atmospheric conditions. Used in ATC for speed assignments and reporting in high-speed flight.
View termManual braking
The act of the flight crew applying the aircraft's wheel brakes by hand or foot, rather than using automatic braking systems, typically during landing rollout or ground operations.
View termMissed approach
A published procedure to be followed when an instrument approach cannot be completed to a landing due to loss of required visual reference or ATC instruction.
View termMode Control Panel
The autopilot interface panel allowing pilots to select, arm, or adjust flight modes such as heading, altitude, and vertical speed for aircraft automation.
View termNavigation Display
An electronic cockpit display providing pilots with route, waypoint, weather radar, and traffic information to support flight navigation and situational awareness.
View termPositive rate
An indication, after takeoff, that the aircraft is climbing and the rate of climb is greater than zero as shown on the vertical speed indicator (VSI). Used by pilots to confirm climb before gear retraction.
View termPre-start
The phase prior to engine start during which pilots perform pre‑start checklists, request clearances, and coordinate with ground services as required.
View termPrimary Flight Display
The main electronic cockpit display providing essential flight information such as attitude, airspeed, altitude, and heading; central to flight crew situational awareness.
View termPushback
The procedure of moving an aircraft rearward from a gate or stand using a tow vehicle, under ground control instructions, before taxiing.
View termQFE (Altimeter setting to runway threshold elevation)
An altimeter reference setting in which the altimeter indicates the height above the runway threshold elevation; used for precision approaches (QFE setting).
View termReference landing speed
The speed selected as a reference for final approach and landing, often denoted as Vref; used for approach calculations and stabilized approach criteria.
View termReserve fuel
The quantity of fuel carried on board in addition to all planned requirements, intended for unforeseen circumstances and regulatory compliance.
View termRetard thrust levers
Callout or instruction for pilots to move all engine thrust levers to idle, normally at 20–10 ft AGL during Airbus landings.
View termRoll-out mode
A mode of the autopilot or autoland system engaged after touchdown, controlling the aircraft's direction and deceleration along the runway centerline until low speed is reached.
View termRunway turn-off
A designated taxiway or exit used by an aircraft to vacate the runway after landing or rejected takeoff.
View termShutdown
The procedure in which the aircraft's engines and systems are switched off after reaching the parking position, ending the flight phase.
View termSlats
Movable aerodynamic surfaces located on the leading edge of the wing, extended to increase lift at low speeds during takeoff and landing.
View termSpeed brake
A flight control surface deployed by pilots to increase drag and reduce airspeed or descent rate, especially during descent and approach phases.
View termSpoilers
Movable surfaces on the wings deployed to reduce lift, increase drag, and assist in decelerating the aircraft after touchdown or during flight descent.
View termStandard departure
A pre-planned IFR departure route (SID) published for use by departing aircraft, providing obstacle clearance and efficient traffic flow.
View termStandard pressure setting (1013 hPa)
The standard sea-level pressure value of 1013.25 hPa (hectopascals) used above transition altitude/level for setting altimeters.
View termSTAR
Standard Terminal Arrival Route: a published IFR arrival procedure that streamlines traffic flow from the enroute phase to the approach at an airport.
View termStep climb
A procedure in which an aircraft increases cruise altitude in steps as weight decreases, optimizing fuel efficiency and performance on long flights. Step climbs are coordinated with ATC and comply with the current flight plan.
View termTail-wind component
The portion of the wind velocity blowing in the same direction as the aircraft's movement or runway orientation, reducing takeoff or landing performance.
View termTake‑off roll
The phase of flight beginning when an aircraft starts its ground run on the runway after take-off clearance, accelerating to lift-off speed.
View termTaxi
To move an aircraft on the surface of an aerodrome under its own power, except when taking off and landing. Used in ATC instructions to direct aircraft ground movements.
View termTaxi-in
The movement of an aircraft under its own power from the runway or landing area to the assigned parking position or gate after landing.
View termTaxiway
A defined path at an aerodrome, established for the taxiing of aircraft and intended to provide a link between one part of the aerodrome and another, including runways, aprons, and hangars.
View termThrust reduction
A standard procedure to reduce engine thrust from take-off power to a lower, climb-appropriate setting at a specific altitude or waypoint after take-off.
View termThrust reverser
A device that redirects the engine's thrust forward to help slow the aircraft after landing, typically activated on touchdown.
View termTop of climb
The defined point in a flight where the aircraft completes its climb and levels off at the planned cruise altitude. Marked in flight planning systems and often referenced in ATC communications.
View termTop of descent
The calculated point during cruise at which an aircraft initiates descent from cruising altitude toward destination, usually determined by onboard flight management systems.
View termTrack angle
The actual direction of an aircraft's path over the ground, expressed as an angle relative to north, independent of heading.
View termTrailing-edge device
A movable aerodynamic surface located on the trailing edge of an aircraft wing, such as a flap, extended to increase lift and control at low speeds, especially during takeoff and landing.
View termTransition altitude
The altitude at or below which the vertical position of an aircraft is controlled by reference to altitudes, and above which by flight levels. Transition altitude is defined for each airport or airspace region.
View termTransition level
The lowest flight level available for use above the transition altitude. Aircraft climbing through the transition altitude use the transition level to set standard pressure.
View termTransition speed
The airspeed at which the transition from one phase of flight to another occurs, often referencing a speed for configuration or regulatory changes (e.g., flaps up).
View termTrue airspeed
The actual speed of an aircraft relative to the air mass through which it is flying, corrected for altitude and temperature.
View termTurbulence
Irregular motion of the air resulting from eddies and vertical currents, often causing bumpiness or abrupt altitude changes for aircraft. Pilots report turbulence to ATC for safety.
View termVerify Flight-Mode Annunciator indications
Instructs crew to check and confirm that the Flight-Mode Annunciator (FMA) on the Primary Flight Display is showing the correct mode annunciations in accordance with expected aircraft status or flight phase.
View termWay-points
Specific geographical locations defined by coordinates used to guide aircraft along a flight route or procedure.
View term