Aviation Terminology

Aviation has its own language of hundreds of aeronautical terms. Here you will find the most common aviation terms as well as some not so common aviation terms. Some come from French, German, even military usage, but remember that English is always the official language of aviation.

Absolute Altitude – The vertical distance between the aircraft and ground level.

Absolute Ceiling – The highest altitude an aircraft can fly at maximum throttle while maintaining level height and constant airspeed.

Accelerated Stall – A stall that occurs at a higher airspeed than a normal stall due to a higher load factor (g).

Automatic Direction Finder (ADF) – A navigation system that identifies the relative bearing of an aircraft based on a radio beacon transmitting in the MF or LF bandwidth.

Adiabatic Lapse Rate – The rate at which temperature changes due to increasing and decreasing altitude, under conditions of thermal equilibrium.

Adverse Yaw – When an aircraft turns in the opposite direction of a roll due to use of ailerons and the difference in lift and drag of each wing.

Aeronautical Information Manual (AIM) – An official Federal Aviation Administration (FAA) publication that details proper pilot operation within the US National Airspace System, including Air Traffic Control (ATC) and aviation safety.

Above Ground Level (AGL) – The vertical distance measured between the aircraft and a specific land mass.

Aileron – The movable, hinged flight control surfaces that are used in pairs with opposite motions to control the roll of an aircraft.

Air Defense Identification Zone (ADIZ) – The airspace over both water and land within which the identification, location, and control of civil aircraft is required in the interest of national security.

Air Speed Indicator (ASI) – A pitot-static flight instrument that indicates airspeed of an aircraft through an air mass in miles per hour, knots, or both.

Air Taxi Operator – An aircraft company that operates under FAR Part 135. The aircraft must be originally designed to have no more than 60 passenger seats or a cargo payload of 18,000 lbs and carries cargo or mail on either a scheduled or charter basis, and/or carries passengers on an on-demand basis or limited scheduled basis.

Air Traffic Control (ATC) – A ground-based service that ensures safety of air traffic by directing aircraft in the area during take-off, landing, and while flying in the designated airspace.

Airfoil – The cross-sectional shape of a wing, blade, turbine, or rotor that produces lift.

Altimeter – An instrument that measures an object’s altitude above a fixed surface.

Altitude Indicator – An instrument that indicates aircraft orientation relative to earth’s horizon.

Angle of Attack – The angle between a reference line on an airfoil and the direction of the oncoming air.

Angle of Incidence – The angle at which a reference line on an airfoil is perpendicular to the aircraft’s longitudinal surface axis.

Anhedral – The downward angle of aircraft wings from the horizontal cross-section of the wings.

Annual Inspection – A required aircraft inspection every 12 calendar months.

Apron – The paved area at an airport where aircraft park, fuel, load, and unload.

Automatic Terminal Information Service (ATIS) – A continuous broadcast of pre-recorded aviation information available to pilots around specific terminals. The information is constantly updated and designed for mass spreading of relevant information, which is particularly useful at busy airports.

Avionics Master Switch – A single switch that controls the electrical power for an aircraft’s electronic communication and navigation instruments.

Base Leg – The flight path in an airport pattern that runs in the runway landing direction.

Blade Angle – The angle between the reference line of a propeller blade and a plane perpendicular to the axis of rotation.

Bleed Air – Hot compressed air produced during the compressor stage of aircraft engine operation.

Calibrated Airspeed – The indicated airspeed corrected for position and instrument error.

Camber – The convexity of curve on an aircraft wing.

Cargo – Goods carried on an aircraft.

Ceiling – The height of the lowest cloud layer or obscuring phenomena that is reported as “broken”, “overcast”, or “obscuration”, and not classified as “thin” or “partial”.

Center of Gravity (CG) – The longitudinal and lateral point over which the aircraft would balance.

Charter – The business of renting all seats on an aircraft rather than a commercial flight where seats are sold individually.

Chord Line – The imaginary straight line running between the airfoil’s leading and trailing edges.

Clearance – The authorization provided by air traffic control for aircraft to proceed with a particular action in controlled airspace, which is designed to prevent aircraft collisions.

Climb – The act of increasing aircraft altitude, typically to a designated level.

Common Traffic Advisory Frequency (CTAF) – A radio frequency used for air-to-air communication, allowing continued aircraft operation at non-towered airports or outside of tower operating hours.

Commuter – An aircraft category outlined by the FAA as “limited to propeller-driven, multi-engine airplanes that have a seating configuration, excluding pilot seats, of 19 or less, and a maximum certificated takeoff weight of 19,000 pound or less. The commuter category operation is limited to any maneuver incident to normal flying, stalls (except whip stalls), and steep turns, in which the angle of bank is not more than 60 degrees.”

Constant-Speed Propeller – A propeller designed to maintain a consistent engine RPM by automatic increases and decreases of the blade pitch.

Contrail – A streak of condensed water vapor in the air due to the heat produced by aircraft engines at high altitudes.

Controlled Airspace – Designated airspace within which Air Traffic Control provides aircraft movement instructions and regulations.

Course Deviation Indicator (CDI) – A navigational instrument that displays the lateral course deviation. When the aircraft is flying left of the selected course, the needle deflects proportionally to the right. When the aircraft is flight right of the selected course, the needle deflects proportionally to the left.

Crosswind – Wind that is blowing perpendicular to the aircraft course.

Descent – The act of decreasing aircraft altitude, typically to a designated level.

Distance Measuring Equipment (DME) – Radio navigation technology used to measure the distance between the aircraft and a ground station.

Distress – An internationally-recognized signal for danger and need for immediate assistance.

Downwind Leg – A flight path parallel to but running the opposite direction of the runway intended for landing.

Drag – A parallel and opposing force to an aircraft’s motion through the air.

Elevator – Horizontal surfaces that control aircraft pitch and are typically hinged to the stabilizer.

Empennage – Another phrase for the tail of an aircraft, which provides stability during flight.

Estimated Time en Route (ETE) – The amount of time you will spend traveling to a destination.

Estimated Time of Arrival (ETA) – The time you will arrive at a destination, based on the local time.

Feathering – The act of adjusting variable pitch propellers such that the the blades are in line with airflow and overall drag is reduced.

Ferry Flight – A flight intended to return an aircraft to base; deliver a new aircraft from the manufacturer to the purchaser; move an aircraft from one operations base to another; or moving an aircraft for the purpose of maintenance.

Final Approach – A flight path running in the direction of the runway intended for landing that ends with a landing.

Firewall – A fire-resistant bulkhead that is situated between the engine and other aircraft areas.

Fixed Base Operator (FBO) – An organization at an airport that offers aviation services, such as hangar, parking, and tie-down space; airplane maintenance and rentals; and fuel.

Flaps – Flaps are a kind of high-lift device used to increase the lift of an aircraft wing at a given airspeed. Flat devices, typically located on the edges of a an aircraft wing, that control lift at specific speeds.

Flare – A maneuver that typically occurs during the landing stage of an aircraft. The aircraft nose is pointed upwards, which lowers the descent rate in preparation for landing.

Flight Deck – An area at the front of airplane where the pilot and aircraft controls are situated.

Flight Plan – Formatted information provided by pilots or dispatchers regarding an upcoming flight, including details such as destination, path, timing, etc.

Fuselage – The central portion of an aircraft, which is intended to house the flight crew, passengers, and cargo.

General Aviation – The division of civil aviation aircraft operations that includes all but commercial air transport and aerial work.

Glass Cockpit – A term used to describe an aircraft that is fully equipped with electronic, digital flight instrument displays, instead of analog-style gauges.

Gross Weight – The aircraft weight including people, cargo, fuel, etc.

Ground Effect – The increasing lift and decreasing drag that occurs as a result of an aircraft’s wings as it gets closer to the ground.

Groundspeed – The horizontal speed of an aircraft relative to the surface below.

Hangar – A building made to hold aircraft for storing, maintenance, assembly, etc.

Horizontal Stabilizer – The horizontal stabilizer prevents up-and-down, or pitching, motion of the aircraft nose.

Hypoxia – A condition caused by low levels of oxygen that can lead to dizziness, disorientation, etc, posing extreme danger to pilots operating aircraft at high altitudes.

Instrument Flight Rules (IFR) – Regulations that define aircraft operations when pilots an not able to operate using visual references.

Instrument Landing System (ILS) – A ground-based system that provides directional information for aircraft attempting to land in low visibility situations.

Indicated Airspeed (IAS) – The speed of an aircraft displayed on the airspeed indicator, which is determined by the pitot-static tube and does not take into account any outside factors.

Instrument Meterological Conditions (IMC) – Weather conditions that describe a situation where pilots are not able to operate using visual references.

Knot – A measurement of speed that takes into account nautical miles: 1 knot = 1 nautical mile per hour = 6076 feet per hour. 1 mph =1 mile per hour = 5280 feet per hour.

Laminar-Flow Airfoil – The smooth airflow over an aircraft wing with minimized drag.

Lift – The force that directly opposes aircraft weight, generated primarily by the wings.

Load Factor (g) – The smooth airflow over an aircraft wing with minimized drag.

Longitudinal Axis – The directional that runs horizontally from the aircraft nose to tail.

Mach – The ratio of aircraft speed to the speed of sound through the medium where the aircraft is traveling.

Magnetic Compass – The directional orientation of an aircraft according to the geomagnetic field.

Magnetic Deviation – The error produced by the unavoidable magnetic impact of aircraft materials.

Magnetic North – Unlike the geographical north (North Pole), this point is the location indicated as North by where the compass points.

Magneto – An aircraft engine component that generates high voltage to ignite spark plugs.

Mean Sea Level (MSL) – The average level of the surface an ocean used as a basis for vertical measurements.

METAR – A pilot weather report delivered on a continuous basis.

Operating Limitations – Restrictions defined by an aircraft manufacturer including airspeed, weight, etc.

Overshoot – Landing air craft beyond the runway.

Payload – The weight of the content carried in an aircraft, including passengers, pilots, cargo, etc.

Pilot in Command (PIC) – The designated individual that is responsible for safe aircraft operations during flight.

Pitch – The movement of an aircraft, characterized by the nose and tail rising and falling.

Pitot Tube – A small device located on the front outside edge of an airfoil, used to measure air pressure.

Primary Flight Display (PFD) – The main screen used by pilots in aircraft containing an electronic flight instrument system.

Propeller – A piece of aircraft equipment that contains rotating blades, creating engine thrust.

Roll – Aircraft rotation along the longitudinal axis, which runs from the nose to tail.

Rudder – An aircraft surface used to control the yaw movement.

Runway – A “defined rectangular area on a land aerodrome prepared for the landing and takeoff of aircraft”.

Runway End Safety Area (RESA) – A surface located beyond the runway designated as a place for aircraft to enter in an attempt to minimize risk during unplanned occurrences, such as an overshoot.

Short Field – A runway that is shorter in length and requires aircraft to minimize the amount of runway used when taking off or landing.

Sideslip – An aircraft movement that typically aligns with the lateral force of the wind and results in a sideways flow.

Skid – The sliding and outward pivoting movement of the aircraft that occurs as a result of a shallow turn.

Slip – The sliding and inward pivoting movement of the aircraft that occurs as a result of a steep turn.

Soft Field – A runway that is not paved and made of elements such as dirt or grass.

SQUAWK – A four-digit code given to an aircraft by ATC to allow for simple identification of an aircraft in a given region.

Stall – The condition that occurs as a result of an aircraft exceeding it’s angle of attack and therefore experiencing decreased lift.

Standard Rate Turn – A turn that an aircraft makes at a rate of 3°/second or a 360° turn in two minutes.

Straight-and-Level Flight – Maintaining a consistent heading and altitude during flight.

Tail – The rear aircraft structure that provides aerodynamic stability.

Tarmac – The paved area at an airport where aircraft park, fuel, load, and unload.

Threshold – The area of a runway, designated with particular markings, indicating the beginning of a runway.

Throttle – A device that controls the amount of power outputted by the engine.

Thrust – A force which opposes aircraft drag and is created by the engines to propel the aircraft forward.

Torque – A force that is intended to produce rotation.

Touch-and-Go – An aircraft maneuver used to practice landing techniques by simply landing on the runway and taking off once more without coming to a full stop.

Transponder – An electronic device on airplanes that generate an output code, which is used for ATC identification purposes.

Trim Tab – Small surfaces on the trailing edge of a bigger control surface used to counteract the aerodynamic forces on the bigger control surface.

True Airspeed – The speed of an aircraft is the speed corrected for the errors caused by altitude and temperature.

True Altitude – The vertical height of an aircraft above Mean Sea Level (MSL).

Upwind Leg – The flight path in an airport pattern that runs parallel to the runway landing direction, along the same direction the aircraft will be landing.

Useful Load – The weight of the items that can be taken out of the aircraft, including fuel, passengers, cargo, pilots, etc.

Vertical Speed Indicator (VSI) – A device that provides the feet per minute (fpm) rate at which an aircraft is climb or descending.

Very High Frequency (VHF) Omni-Directional Range (VOR) – A short-range radio aircraft navigation system that allows equipped aircraft to receive directional information through radio signals from ground-based beacons.

Visual Flight Rules (VFR) – Regulations that define aircraft operations when pilots are able to operate using visual references.

VFR On Top – The condition where IFR conditions exist, however VFR conditions exact above the cloud layer.

Visual Meteorological Conditions (VMC) – Weather conditions that describe a situation where pilots are able to operate using visual references.

Wind Shear – An abrupt change in horizontal or vertical wind direction.

Yaw – The movement of an aircraft, characterized by the nose moving side-to-side.

Yoke – The aircraft control devices used by pilot for changes in attitude, as well as pitch and roll movement.