Aviation Glossary

An inspection required every 100 hours of flight time for aircraft used for hire...

The angle between the chord line of an airfoil and the relative wind. As AoA inc...

The ratio of wingspan to mean chord. High aspect ratio wings (long and narrow) p...

The cross-sectional shape of a wing, blade, or sail designed to produce aerodyna...

The tendency of an aircraft to yaw in the opposite direction of a roll input. Ca...

Hinged surfaces on the trailing edge of each wing near the wingtips that control...

The barometric pressure adjusted to sea level used to set the altimeter so it re...

The mass of air per unit volume, which decreases with altitude, increasing tempe...

The highest level of pilot certification required for acting as pilot in command...

A surveillance technology where aircraft determine position via GPS and broadcas...

A gyroscopic flight instrument displaying the aircraft pitch and bank attitude r...

A barometric instrument measuring altitude by sensing atmospheric pressure chang...

An instrument measuring indicated airspeed by comparing pitot (dynamic plus stat...

A small gas turbine engine in the aircraft tail that provides electrical power a...

A service provided by ground-based controllers directing aircraft movement in co...

An authorization by ATC for an aircraft to proceed under specified conditions. C...

A continuous broadcast of recorded airport information including weather, active...

A digital data link system for transmitting messages between aircraft and ground...

The ATC facility providing separation services for IFR aircraft in the enroute p...

Over-reliance on automated systems leading to reduced pilot monitoring and degra...

Symptoms reportedly caused by exposure to contaminated bleed air from engine oil...

A systematic approach to mental processes used by pilots to determine the best c...

Airline Transport Pilot Certification Training Program required before taking th...

The condition of an aircraft being safe for flight, meeting all applicable certi...

A comprehensive inspection required every 12 calendar months for aircraft operat...

The runway length required to accelerate to V1 and then bring the aircraft to a ...

The tendency of the atmosphere to resist or enhance vertical motion. Stable air ...

The rate at which a parcel of air changes temperature as it rises or descends wi...

A structured verbal review of the planned approach procedure including minimums,...

A downward angle of the wing from root to tip, opposite of dihedral. Used on som...

Various lighting systems aiding pilots during night operations including runway ...

A configuration of signal lights extending outward from the runway threshold pro...

A gearbox driven by the engine that powers accessories including generators, hyd...

A device that processes raw pitot-static and temperature data into calibrated fl...

A principle stating that as the velocity of a fluid increases, its static pressu...

The thin layer of air immediately adjacent to an aircraft surface where friction...

Compressed air extracted from the engine compressor section used for cabin press...

The runway length where the accelerate-stop distance equals the accelerate-go di...

Strategies to reduce bird strike risk including checking bird activity reports, ...

The point at which an aircraft would balance if suspended. CG position affects s...

The point on an airfoil where the total aerodynamic force is considered to act. ...

The curvature of an airfoil, specifically the asymmetry between the upper and lo...

The Mach number at which airflow over some part of the aircraft first reaches th...

Flight in which the ball in the slip-skid indicator is centered, meaning there i...

The height above ground level of the lowest broken or overcast cloud layer. Ceil...

Turbulence in cloud-free conditions, typically found near the jet stream and at ...

The leading edge of an advancing cold air mass displacing warmer air. Cold front...

The intended direction of flight measured in degrees from north. The course may ...

Controlled airspace surrounding the busiest airports requiring ATC clearance for...

Controlled airspace around medium-traffic airports requiring two-way radio commu...

A training methodology to improve aviation safety by optimizing the use of all a...

A needle showing lateral displacement from the desired course, whether VOR radia...

An accident where an airworthy aircraft is flown into terrain, water, or obstacl...

A disruption of normal airflow through the engine compressor causing a stall of ...

A device that mixes fuel with air for combustion in a piston engine. Carburetors...

Ice formation in the carburetor venturi and throttle body caused by fuel evapora...

A frequency designated for pilot self-announce of position and intentions at air...

A text-based communication system between ATC and pilots using data link instead...

The ATC facility and frequency providing takeoff, landing, and traffic pattern s...

The body natural 24-hour biological clock that regulates sleep-wake cycles. Disr...

A pilot certificate authorizing the holder to give flight training and ground in...

A flight instructor certificate authorizing the holder to give instrument flight...

A precision approach with decision height between 100 and 200 feet and runway vi...

The lowest-minimum precision approach category. CAT IIIA: DH 100 feet, RVR 700 f...

A crash-protected device recording cockpit audio including crew conversations, r...

The engine whose failure would most adversely affect aircraft performance and ha...

A mode where engine igniters remain continuously energized to provide automatic ...

The fix, point, or route to which an aircraft is cleared by ATC. If the clearanc...

The ratio of height gained to horizontal distance traveled, expressed as a perce...

A runway with more than 25% of its surface covered by water, snow, slush, or ice...

An apparent force caused by the Earth rotation that deflects moving air to the r...

A systematic list of actions and checks performed during various phases of fligh...

The equivalent altitude representing the air pressure inside the pressurized cab...

The window of circadian low between 0200 and 0600 local time when the human body...

An oscillatory motion combining yaw and roll, common in swept-wing aircraft with...

The process of removing ice, snow, or frost from aircraft surfaces before takeof...

A navigation method of estimating current position by advancing a known position...

Regulations limiting the number of hours a pilot can fly and requiring minimum r...

The height during a precision approach at which the pilot must decide to land or...

A takeoff using less than maximum engine thrust to reduce engine wear, noise, an...

A curved instrument approach segment flown at a constant DME distance from a VOR...

A controlled emergency landing on water. Proper technique involves landing paral...

The process of determining density altitude from pressure altitude and temperatu...

The response of an aircraft over time following a disturbance. An aircraft may o...

Uncontrolled explosive combustion in a piston engine cylinder caused by excessiv...

A digital communication system between aircraft and ground stations for transmit...

The movable surface on the horizontal stabilizer that controls pitch. Deflecting...

The maximum time an aircraft can remain airborne with a given fuel load. Maximum...

The European Union agency responsible for civil aviation safety regulation. EASA...

A gauge measuring the temperature of exhaust gases leaving the engine. EGT is us...

The ratio of turbine discharge pressure to compressor inlet pressure, used as a ...

An integrated engine and systems monitoring display used in Boeing and other air...

An altimeter that provides digitized altitude information to the transponder for...

Flight procedures with one engine inoperative in a multi-engine aircraft. Critic...

A series of events or errors that combine to cause an accident. Breaking any sin...

A device that transmits a distress signal on 121.5 MHz and 406 MHz upon impact o...

A hinged surface on the trailing edge of the wing that increases both lift and d...

A component of parasite drag caused by the shape of an aircraft creating pressur...

A cloud at ground level that reduces visibility below 1 kilometer. Types include...

The boundary between two different air masses. Cold fronts bring rapid weather c...

A standard pressure altitude expressed in hundreds of feet with the altimeter se...

The rules and regulations governing aviation in the United States, found in Titl...

A display system showing command bars on the attitude indicator that guide the p...

The process of calculating required fuel for a flight including taxi, trip, cont...

A computerized system that manages all aspects of engine performance. FADEC auto...

Rotating propeller blades to a nearly streamlined position (edge into the wind) ...

A fuel delivery system that meters fuel directly into the cylinder intake port o...

A geographical position determined by visual reference, by one or more radio nav...

A document filed with ATC containing intended flight details including route, al...

A crash-protected device that records aircraft parameters including altitude, ai...

A flight for the purpose of repositioning an aircraft or delivering it to a new ...

The pitch-up maneuver performed just before touchdown to reduce the rate of desc...

The intentional jettison of fuel in flight to reduce aircraft weight to maximum ...

The ratio of horizontal distance traveled to altitude lost in unpowered flight. ...

The vertical guidance component of an ILS providing a descent path typically set...

A satellite-based navigation system providing precise three-dimensional position...

The actual speed of the aircraft over the ground, determined by true airspeed mo...

The shortest distance between two points on the surface of a sphere. Long-haul f...

A cockpit featuring electronic flight displays (LCD or LED) replacing traditiona...

A system that alerts pilots to potential controlled flight into terrain by monit...

The procedure of abandoning an approach or landing attempt and climbing away for...

The international emergency frequency 121.5 MHz that all ATC facilities and many...

A deadly vestibular illusion where a pilot in a gradual bank does not sense the ...

Loss of consciousness caused by excessive positive G forces reducing blood flow ...

An accelerometer measuring load factor in G units. Shows current, maximum positi...

The wind component parallel to and opposing the aircraft direction. Headwinds re...

A gyroscopic instrument showing aircraft magnetic heading without the oscillatio...

An engine start where ITT or EGT exceeds the allowable limit, indicating insuffi...

The transfer of radar identification and communication responsibility from one A...

A condition of excessive breathing rate that reduces blood carbon dioxide levels...

A transparent display projecting flight data onto the windscreen, allowing pilot...

An engine start where the engine lights off but does not accelerate to idle RPM....

A condition where a layer of water separates the tire from the runway surface, e...

A flight time recording device measuring elapsed time from engine start or weigh...

A long-range radio communication system using frequencies between 2 and 30 MHz f...

Drag created as a byproduct of lift generation, caused by wingtip vortices defle...

A model atmosphere used for aircraft performance calculations. At sea level: 15 ...

A precision approach system providing lateral guidance via the localizer and ver...

The airspeed shown on the cockpit airspeed indicator, derived from pitot and sta...

Flight rules requiring navigation solely by reference to flight instruments. IFR...

A qualification added to a pilot license allowing flight under IFR in instrument...

A check required for instrument-rated pilots who have not met instrument currenc...

The United Nations specialized agency that sets international standards and reco...

Temperature measured between the high-pressure and low-pressure turbine stages. ...

A point defined by the crossing of two VOR radials, a VOR radial and a DME dista...

The systematic cross-check of flight instruments during instrument flight. The r...

A takeoff initiated from an intersection of a taxiway and runway rather than fro...

High-altitude airways from 18000 feet to FL450 defined by VOR radials. Designate...

The ratio of total lift to aircraft weight, expressed in G units. In straight an...

The lateral guidance component of an ILS providing precise runway centerline ali...

Localizer Performance with Vertical Guidance approach using WAAS GPS providing p...

GPS-based lateral guidance for non-precision approaches. LNAV approaches use a m...

Operations where a pilot is cleared to land and hold short of an intersecting ru...

A nighttime wind blowing from land to sea caused by the land cooling faster than...

An ATC instruction authorizing an aircraft to taxi onto the runway and hold in t...

Visual signals using a directional light from the control tower to communicate w...

The ratio of true airspeed to the local speed of sound. Mach 1.0 is the speed of...

The maximum speed at which full control deflection will not cause structural dam...

The maximum certified weight at which an aircraft is allowed to attempt takeoff....

A small-scale intense downdraft that produces damaging divergent winds at the su...

The angular difference between true north and magnetic north at a given location...

A certificate issued by an Aviation Medical Examiner attesting to pilot fitness....

A document approved by the aviation authority listing equipment that may be inop...

An electronic display showing navigation, weather, engine, traffic, and terrain ...

A procedure executed when an instrument approach cannot be completed to a landin...

The international distress call indicating an aircraft is in grave and imminent ...

The lowest altitude providing at least 1000 feet of obstacle clearance within a ...

The lowest altitude on an airway that provides required obstacle clearance. Navi...

Radio beacons on the ILS approach path providing range information. Outer marker...

A nose-down pitching tendency that occurs when shock waves on the wing move the ...

The lowest altitude at which ATC may issue radar vectors providing 1000 feet (20...

The rotational speed of the low-pressure compressor and fan in a turbofan engine...

The rotational speed of the high-pressure compressor in a turbofan engine, expre...

A standardized set of words representing each letter of the alphabet used in avi...

Permanent hearing damage from prolonged exposure to high noise levels in the coc...

An instrument approach with lateral guidance but no electronic glidepath. VOR, N...

A thick grey cloud layer producing steady continuous precipitation over a wide a...

The process by which the eyes adapt to low light conditions using rod cells inst...

The upward forcing of air when wind encounters mountain terrain. This mechanical...

The weight of the aircraft including crew, fluids, and standard equipment but ex...

Mandatory and voluntary reporting of safety events including incidents, accident...

A landing at a weight exceeding the maximum certificated landing weight. May be ...

Asymmetric propeller thrust that causes yaw, most noticeable at high power and h...

Rotation of the aircraft about its lateral axis, controlled by the elevator or s...

The indicated altitude when the altimeter is set to 29.92 inHg (1013.25 hPa). Us...

A weather observation made by a pilot during flight, reporting actual conditions...

Navigation by visual reference to landmarks on the ground such as rivers, highwa...

FAR Part 91 covers general operating and flight rules applicable to all civil ai...

FAR Part 121 governs scheduled air carrier operations with high safety standards...

FAR Part 135 covers commuter and on-demand air carrier operations. It has strict...

The first pilot certificate allowing a pilot to fly as pilot in command of an ai...

An ICAO framework replacing sensor-specific navigation requirements with perform...

A reciprocating internal combustion engine driving a propeller for aircraft prop...

The international urgency call indicating a condition concerning the safety of t...

The person who has final authority and responsibility for the operation and safe...

An instrument approach with both lateral and vertical electronic guidance to the...

A visual aid of four light units beside the runway showing the aircraft position...

A radio call reporting aircraft position, altitude, and intentions. Mandatory at...

Airport lighting activated by radio transmissions on the CTAF frequency. Typical...

The useful load that generates revenue, including passengers, baggage, and cargo...

The process of maintaining cabin altitude at a comfortable level while the aircr...

A sudden physical or mental inability of a pilot to perform duties. Can be subtl...

A long-period oscillation of aircraft pitch and altitude at essentially constant...

Step-by-step taxi instructions from ground control given one turn at a time for ...

A course reversal maneuver used to establish an aircraft on an inbound approach ...

The direction of airflow relative to the aircraft, which is equal and opposite t...

The movable surface on the vertical stabilizer that controls yaw. The rudder is ...

The maximum distance an aircraft can fly with a given fuel load without refuelin...

The range over which the pilot of an aircraft on the runway centerline can see t...

The ratio of actual water vapor in the air to the maximum amount it could hold a...

A specification for RNAV systems that includes onboard monitoring and alerting c...

The reduction of vertical separation from 2000 to 1000 feet between FL290 and FL...

An instrument that measures exact height above the ground using radar signals. A...

The decision to abort a takeoff and bring the aircraft to a stop on the remainin...

The pilot repetition of an ATC clearance or instruction to confirm correct recep...

Sudden loss of cabin pressure due to structural failure or door seal breach at a...

Rules determining which aircraft has priority in various situations. Aircraft in...

An unannounced FAA inspection of aircraft documents and pilot certificates durin...

Painted markings on runway surfaces including threshold markings, centerline, to...

A pair of synchronized flashing strobe lights located at the runway threshold to...

An aerodynamic condition where the critical angle of attack is exceeded and the ...

An aggravated stall where the aircraft autorotates about its vertical axis while...

The procedure to recover from a spin, typically involving: power idle, ailerons ...

An uncoordinated flight condition where the aircraft moves sideways toward the i...

A wing design where the leading edge is angled backward, delaying the onset of c...

Significant Meteorological Information advisory issued for hazardous weather phe...

A narrow band of active thunderstorms forming along or ahead of a cold front. Sq...

A four-digit octal code set on the aircraft transponder for ATC identification. ...

An ATC authorization for VFR aircraft to operate within surface-based controlled...

An opening in the aircraft skin that senses ambient atmospheric pressure for the...

An approach where the aircraft is in the proper landing configuration, on the co...

A precision landing technique to achieve minimum landing distance. Requires a st...

A published departure procedure providing obstacle clearance and noise abatement...

A published arrival procedure routing traffic from the enroute environment to an...

A physiological response to an unexpected event causing a brief period of confus...

A flight in which a student pilot is the sole occupant of the aircraft. Requires...

A system that alerts the pilot to an impending stall through an aural warning (h...

A computer-generated three-dimensional display of the external terrain based on ...

Low-level lumpy grey cloud layer common in marine environments. May produce ligh...

Flight control surfaces or devices deployed to increase drag and reduce speed wi...

James Reason accident causation model where multiple defensive layers (like slic...

The initial tendency of an aircraft to return toward its original condition afte...

The maximum loads an aircraft structure is designed to withstand. Normal categor...

A specific departure time assigned to an aircraft by ATC flow control to manage ...

A formal top-down organizational approach to managing safety risk. SMS includes ...

The emergency transponder code set when declaring an emergency. Squawking 7700 t...

The transponder code indicating communication failure. When a pilot loses radio ...

Backup flight instruments providing essential data when primary systems fail. Ty...

A computer-generated three-dimensional terrain display on the primary flight dis...

Aircraft communication via satellite providing voice and data connectivity over ...

The reaction force to propeller rotation that tends to roll the aircraft in the ...

Adjustable surfaces or tabs that allow the pilot to relieve control pressure for...

Irregular atmospheric motion causing an aircraft to experience bumps, altitude c...

A convective weather phenomenon producing lightning, heavy rain, turbulence, hai...

The boundary between the troposphere (where weather occurs) and the stratosphere...

The rate at which air temperature decreases with altitude. The standard lapse ra...

The actual speed of the aircraft through the air mass, corrected for altitude an...

A regulatory notice filed with the FAA temporarily restricting certain aircraft ...

An authorization on a pilot certificate to fly a specific type of aircraft requi...

An aircraft electronic device that responds to ATC radar interrogation by transm...

An airborne system that monitors transponder signals from nearby aircraft and pr...

Ground movement of an aircraft under its own power on airport surfaces. Taxi ope...

The forward force produced by an engine to propel the aircraft. In jet engines, ...

A mechanism that redirects engine exhaust forward to provide braking force durin...

The time from loss of oxygen supply until a person can no longer take corrective...

The first 3000 feet of the runway or the first third of the runway, whichever is...

The generic term for systems including EGPWS that provide terrain awareness. TAW...

ATC information about other aircraft in the vicinity using clock position, dista...

The actual height above mean sea level. True altitude is what the altimeter shou...

A condition where the pilot has more tasks to perform than can be effectively ma...

A narrowing of attention focus that causes a pilot to fixate on one task or inst...

The speed regime between Mach 0.8 and 1.2 where both subsonic and supersonic air...

A small adjustable surface on a primary control surface that provides aerodynami...

Painted markings on airport surfaces including yellow taxiway centerlines, runwa...

The additional lift gained by a helicopter when transitioning from hover to forw...

A non-government air-ground radio communication station providing airport adviso...

A metropolitan area that is warmer than surrounding rural areas due to human act...

Designated airspeeds important to the operation of an aircraft, typically shown ...

The stall speed or minimum steady flight speed in landing configuration with ful...

The never-exceed speed, indicated by a red line on the airspeed indicator. Excee...

Maximum structural cruising speed, the upper limit of the green arc on the airsp...

Rotation speed during takeoff at which the pilot applies back pressure to raise ...

Takeoff safety speed that must be attained by 35 feet above the runway. The mini...

Reference landing speed, typically 1.3 times VS0 for the landing weight and conf...

Minimum control speed with the critical engine inoperative. Below VMC, direction...

A ground-based radio navigation aid transmitting radials in all directions. Pilo...

An instrument showing rate of climb or descent in feet per minute by measuring t...

An IFR approach where the pilot proceeds visually to the runway with ATC authori...

Optical illusions affecting approach judgment including narrow runways appearing...

Low-altitude federal airways below 18000 feet MSL defined by VOR radials. Design...

Automated vertical flight path management by the FMS or GPS. VNAV can provide ve...

A defined point on a non-precision approach from which normal descent from MDA t...

A system of lights beside the runway indicating approach angle. Two-bar VASI sho...

An IFR clearance allowing a pilot to fly in VFR conditions above clouds while ma...

A circular airflow pattern created at the wingtips where high-pressure air below...

A vertical or angled extension at the wingtip that reduces induced drag by weake...

Turbulent air generated by wingtip vortices behind an aircraft, particularly dan...

The process of calculating aircraft total weight and center of gravity position ...

A sudden change in wind speed or direction over a short distance. Low-level wind...

A GPS augmentation system providing improved accuracy, integrity, and availabili...

An airborne radar system that detects precipitation and turbulence ahead of the ...

The ability to prioritize tasks and manage time effectively during various phase...

Changes in center of gravity during flight due to fuel burn, passenger movement,...

The continued rotation of a failed engine propeller or fan driven by airflow. Wi...

A preflight consultation of current and forecast weather conditions obtained fro...

Rotation of the aircraft about its vertical axis, controlled by the rudder. Yaw ...

Coordinated Universal Time (UTC) used as the standard time reference in aviation...