Reference

Pilot glossary

165 private pilot terms in plain English, each linked to the course lesson that teaches it.

#

100-hour inspection: An inspection required every 100 hours of time in service for aircraft used for hire or for flight instruction provided by the person furnishing the aircraft (14 CFR 91.409). Learn it →

A

ACS (Airman Certification Standards): The FAA document that lists every task, knowledge, risk management and skill standard tested on the knowledge test and checkride. Learn it →
ADM (aeronautical decision-making): A systematic approach to assessing risks and making the best decision in a given situation. Learn it →
ADS-B Out: Equipment that broadcasts an aircraft's GPS position, altitude and speed to ATC and other aircraft. Required in Class A, B and C airspace, the Mode C veil and other areas (14 CFR 91.225). Learn it →
Adverse yaw: The tendency of the nose to yaw away from the direction of a turn, caused by extra induced drag on the wing with the down aileron. Corrected with rudder. Learn it →
AGL (above ground level): Height measured above the terrain directly below. Cloud heights in METARs and TAFs are AGL. Learn it →
Aileron: A hinged control surface on the outer trailing edge of each wing that rolls the airplane around its longitudinal axis. Learn it →
AIM (Aeronautical Information Manual): The FAA's official guide to basic flight information and ATC procedures. Not regulatory, but it describes recommended practices.
AIRMET: An in-flight advisory for weather that may be hazardous to light aircraft: Sierra (IFR and mountain obscuration), Tango (turbulence, strong surface winds, low-level wind shear) and Zulu (icing and freezing levels). Learn it →
Airworthiness certificate: The document showing an aircraft met its type design and was in condition for safe operation when issued. Must be displayed in the aircraft. Learn it →
Airworthiness Directive (AD): A legally enforceable FAA rule requiring an inspection, repair or modification to correct an unsafe condition in an aircraft, engine or part. Learn it →
Alert area: Special use airspace with a high volume of pilot training or unusual aerial activity. Flight is allowed; be alert. Learn it →
Alternator: An engine-driven generator that powers the electrical system and charges the battery in flight. Learn it →
Altimeter setting: The local barometric pressure, in inches of mercury, set in the altimeter's Kollsman window so it reads altitude above sea level. Learn it →
Angle of attack (AoA): The angle between the wing's chord line and the relative wind. A wing stalls when it exceeds the critical angle of attack. Learn it →
Annual inspection: A complete inspection required within the preceding 12 calendar months for most general aviation aircraft (14 CFR 91.409). Learn it →
Anti-servo tab: A tab on a stabilator that moves in the same direction as the trailing edge, adding control feel and preventing overcontrol. Learn it →
ARROW: Memory aid for documents required on board: Airworthiness certificate, Registration, Radio station license (international only), Operating limitations, Weight and balance. Learn it →
ATC (air traffic control): The service that provides separation and information to aircraft, through towers, approach control and centers. Learn it →
ATIS (Automatic Terminal Information Service): A continuous recorded broadcast of weather, runway in use and notices at an airport, identified by a phonetic letter. Learn it →
Attitude indicator: A gyroscopic instrument showing the airplane's pitch and bank relative to the horizon. Learn it →

B

BasicMed: An alternative to an FAA medical certificate for eligible pilots who have held a medical certificate after July 14, 2006, with limits on aircraft and operations. Learn it →
Best glide speed: The airspeed that gives the greatest gliding distance per foot of altitude lost, at L/D max. Published in the POH. Learn it →

C

Calendar month: A period that runs to the last day of the month. Something valid for 24 calendar months from March 3 is valid through the end of March two years later. Learn it →
Carburetor ice: Ice forming in the carburetor throat from the cooling of fuel vaporization and the venturi effect. First sign in a fixed-pitch airplane is a drop in RPM. Learn it →
Ceiling: The height above ground of the lowest cloud layer reported as broken or overcast, or the vertical visibility into an obscuration. Learn it →
Center of gravity (CG): The point where the airplane would balance; total moment divided by total weight. Learn it →
Checkride: The FAA practical test: an oral exam and a flight with an examiner, graded against the ACS. Learn it →
Chord line: An imaginary straight line from a wing's leading edge to its trailing edge. Learn it →
Class A airspace: Controlled airspace from 18,000 ft MSL up to and including FL600. IFR only. Learn it →
Class B airspace: Controlled airspace around the busiest airports. Requires an ATC clearance to enter. Learn it →
Class C airspace: Controlled airspace around busy airports with radar approach control. Requires two-way radio communication established before entry. Learn it →
Class D airspace: Controlled airspace around airports with an operating control tower. Requires two-way radio communication established before entry. Learn it →
Class E airspace: All controlled airspace that isn't Class A, B, C or D. Learn it →
Class G airspace: Uncontrolled airspace, mostly close to the ground. Learn it →
Cold front: The leading edge of an advancing cold air mass. Often fast-moving with cumuliform clouds, gusty winds and thunderstorms. Learn it →
Complex airplane: An airplane with retractable landing gear, flaps and a controllable-pitch propeller. Requires an endorsement to act as PIC. Learn it →
Constant-speed propeller: A propeller whose blade angle is adjusted by a governor to hold the RPM selected by the pilot. Learn it →
Convective SIGMET: An advisory for thunderstorms (severe, embedded, lines or widespread), tornadoes and hail of 3/4 inch or more. Learn it →
Coordinated flight: Flight with the inclinometer ball centered, using rudder and aileron together so the airplane neither slips nor skids. Learn it →
Coriolis illusion: An overwhelming tumbling sensation caused by moving the head abruptly during a prolonged turn. Learn it →
Critical angle of attack: The angle of attack at which the wing stalls. It doesn't depend on airspeed, attitude or weight. Learn it →
Cross-country time: For private pilot requirements, flight time that includes a landing at a point more than 50 NM straight-line distance from the original departure point (14 CFR 61.1). Learn it →
Crosswind leg: The traffic pattern leg flown perpendicular to the runway after the upwind leg. Learn it →
CTAF (common traffic advisory frequency): The frequency pilots use to announce their position and intentions at a non-towered airport. Learn it →

D

Datum: The imaginary vertical reference line from which all weight and balance arms are measured. Learn it →
Dead reckoning: Navigation by computing heading, groundspeed and time from known information. Learn it →
Density altitude: Pressure altitude corrected for nonstandard temperature. It's the altitude the airplane performs as if it were at. Learn it →
Detonation: The explosive, uncontrolled burning of the fuel-air mixture in a cylinder, often from too low a fuel grade, a lean mixture or high temperatures. Learn it →
Deviation: Compass error caused by magnetic fields in the airplane itself. Recorded on the compass correction card. Learn it →
Dewpoint: The temperature to which air must be cooled to become saturated. Learn it →
Dihedral: The upward angle of the wings from root to tip, which adds lateral (roll) stability. Learn it →
Displaced threshold: A threshold located down the runway from its beginning. The displaced area can be used for takeoff and rollout, but not for landing. Learn it →
Downwind leg: The traffic pattern leg flown parallel to the runway, opposite the landing direction. Learn it →
DPE (Designated Pilot Examiner): A private individual authorized by the FAA to give practical tests and issue certificates. Learn it →

E

E6B: A flight computer (manual or electronic) for solving wind, time, speed, distance and fuel problems. Learn it →
Elevator: The hinged surface on the horizontal tail that controls pitch. Learn it →
ELT (emergency locator transmitter): A transmitter that activates on impact to help search and rescue find a downed aircraft. Inspected every 12 calendar months. Learn it →
Empennage: The tail section of the airplane: vertical and horizontal stabilizers, rudder and elevator. Learn it →
Endorsement: A signed logbook entry from an instructor authorizing something, like solo flight, a knowledge test or a complex airplane. Learn it →

F

FBO (fixed-base operator): A business at an airport offering fuel, parking, rentals, maintenance or flight training.
Flaps: Hinged surfaces on the inboard trailing edge of the wings that increase lift and drag and lower the stall speed. Learn it →
Flight following: Radar traffic advisories provided by ATC to VFR aircraft when workload permits. Learn it →
Flight review: At least 1 hour of ground and 1 hour of flight training with an instructor, required every 24 calendar months to act as PIC (14 CFR 61.56). Learn it →
Fuel injection: A system that sprays fuel directly into the intake ports instead of using a carburetor; much less prone to induction icing. Learn it →
Fuselage: The main body of the airplane, holding the cockpit, occupants and cargo. Learn it →

G

GFA (Graphical Forecasts for Aviation): The FAA's web tool showing observations and forecasts of clouds, weather, turbulence and icing. Learn it →
Graveyard spiral: A disorienting illusion where a pilot in a prolonged descending turn senses wings-level flight and pulls back, tightening the spiral. Learn it →
Ground effect: Reduced induced drag when flying within about one wingspan of the surface. Causes floating on landing. Learn it →
Groundspeed: The airplane's speed over the ground: true airspeed adjusted for wind. Learn it →
Gyroscopic precession: The tendency of a gyroscope to react to a force 90° ahead in its direction of rotation. Learn it →

H

Heading indicator: A gyroscopic instrument that shows heading without compass errors, but drifts and must be set to the compass periodically. Learn it →
High-performance airplane: An airplane with an engine of more than 200 horsepower. Requires an endorsement to act as PIC. Learn it →
Hold short markings: Two solid and two dashed yellow lines across a taxiway marking a runway holding position. Stop on the solid side. Learn it →
Hyperventilation: Breathing too fast, lowering carbon dioxide in the blood and causing dizziness and tingling. Learn it →
Hypoxia: A lack of oxygen reaching the body's tissues. Types: hypoxic, hypemic, stagnant and histotoxic. Learn it →

I

IACRA: The FAA's online system for airman certificate applications, including student pilot certificates and checkrides. Learn it →
IMC (instrument meteorological conditions): Weather below VFR minimums, requiring flight by reference to instruments.
IMSAFE: A personal fitness checklist: Illness, Medication, Stress, Alcohol, Fatigue, Emotion. Learn it →
Inclinometer: The ball in the turn coordinator that shows whether a turn is coordinated. Learn it →
Induced drag: Drag created as a byproduct of lift. Greatest at high angles of attack and low airspeed. Learn it →
Isogonic line: A line on a chart connecting points of equal magnetic variation. Learn it →

K

Knowledge test: The FAA computer-based multiple-choice exam (the "written"): 60 questions and 70% to pass for private pilot. Learn it →

L

L/D max: The maximum lift-to-drag ratio, the point of least total drag. Flying at it gives the best glide. Learn it →
LAHSO (land and hold short operations): Operations where a landing aircraft is asked to stop before an intersecting runway. Student pilots should not participate. Learn it →
Lateral axis: The axis from wingtip to wingtip. Pitch is rotation around it. Learn it →
Lenticular cloud: A smooth, lens-shaped cloud that signals mountain waves and possible severe turbulence. Learn it →
Load factor: The ratio of the load on the wings to the airplane's weight, in Gs. 2G in a level 60° bank turn. Learn it →
Longitudinal axis: The axis from nose to tail. Roll is rotation around it. Learn it →

M

Magneto: An engine-driven generator that makes its own electricity for the spark plugs, independent of the electrical system. Learn it →
Manifold pressure: The pressure in the engine's intake manifold, used to set power in airplanes with constant-speed propellers. Learn it →
MEF (maximum elevation figure): The large number in each sectional chart quadrangle showing the highest terrain or obstacle plus a margin, in thousands and hundreds of feet MSL. Learn it →
METAR: An aviation routine weather report, usually issued hourly. Learn it →
Microburst: An intense, small-scale downdraft from a thunderstorm that can exceed an airplane's climb capability. Learn it →
Mixture: The ratio of fuel to air going into the engine, adjusted with the mixture control (leaning). Learn it →
MOA (military operations area): Special use airspace for military training. VFR flight is allowed with caution. Learn it →
Mode C veil: The area within 30 NM of a Class B primary airport, surface to 10,000 ft MSL, requiring an altitude-reporting transponder and ADS-B Out. Learn it →
Moment: Weight multiplied by arm, used in weight and balance calculations. Learn it →
MSL (mean sea level): Altitude measured above average sea level. Charts show airport elevations and obstacles in MSL. Learn it →

N

Night (logging): The time between the end of evening civil twilight and the beginning of morning civil twilight (14 CFR 1.1). Learn it →
NOTAM (notice to air missions): A notice of a change or hazard in the national airspace system, like a closed runway or a TFR. Learn it →
NTSB 830: The rules for notifying the National Transportation Safety Board of aircraft accidents and certain incidents. Learn it →

O

OBS (omni bearing selector): The knob on a VOR indicator used to select a course. Learn it →

P

P-factor: Asymmetric propeller loading at high angles of attack that yaws the airplane to the left (in clockwise-turning propellers). Learn it →
PAPI (precision approach path indicator): A row of four lights showing glide path: two white and two red means on path. Learn it →
Parasite drag: Drag not associated with lift: form, interference and skin friction drag. Increases with airspeed. Learn it →
PAVE: A risk checklist: Pilot, Aircraft, enVironment, External pressures. Learn it →
PIC (pilot in command): The pilot with final authority and responsibility for the flight (14 CFR 91.3). Learn it →
Pilotage: Navigation by reference to visible landmarks. Learn it →
PIREP: A pilot weather report. UA is routine; UUA is urgent. Learn it →
Pitot tube: A forward-facing tube that senses ram air pressure for the airspeed indicator. Learn it →
POH (Pilot's Operating Handbook): The manufacturer's handbook for an airplane, with limitations, procedures, performance and weight and balance data.
Practical test: See Checkride. Learn it →
Pressure altitude: The altitude shown with the altimeter set to 29.92 inHg. Used for performance calculations. Learn it →
Pro rata share: An equal share of operating expenses among the pilot and passengers. Private pilots may not pay less than theirs. Learn it →
Prohibited area: Special use airspace where flight is not allowed. Learn it →

R

Radial: A magnetic bearing extending outward FROM a VOR station. Learn it →
Relative wind: The airflow relative to the wing, opposite the flight path. Learn it →
Restricted area: Special use airspace with hazards like artillery firing. Don't enter when active without permission. Learn it →
Rudder: The hinged surface on the vertical tail that controls yaw. Learn it →

S

Sectional chart: The main VFR navigation chart, at a scale of 1:500,000, updated every 56 days. Learn it →
Segmented circle: A ground marker system at non-towered airports showing wind direction and traffic pattern direction. Learn it →
SIGMET: An advisory for severe weather hazardous to all aircraft: severe icing, severe or extreme turbulence, dust or sandstorms and volcanic ash. Learn it →
Skid: Uncoordinated flight with too much rudder for the bank; the ball is to the outside of the turn. Learn it →
Slip: Uncoordinated flight with too little rudder for the bank; the ball is to the inside of the turn. Learn it →
Solo: Flight with the student pilot as the sole occupant, after receiving the required endorsements. Learn it →
Special VFR: An ATC clearance to operate VFR in a surface area below basic VFR minimums, with 1 SM visibility and clear of clouds (14 CFR 91.157). Learn it →
Spin: An aggravated stall where one wing is more stalled than the other, producing a rotating descent. Requires a stall plus yaw. Learn it →
Squawk: The four-digit code set in the transponder. 1200 is VFR, 7500 hijack, 7600 lost communications, 7700 emergency. Learn it →
Stabilator: A one-piece horizontal tail that moves as a unit to control pitch. Learn it →
Stall: Loss of lift when the wing exceeds its critical angle of attack. Learn it →
Standard atmosphere: The reference atmosphere: 15°C and 29.92 inHg at sea level, decreasing about 2°C and 1 inHg per 1,000 ft. Learn it →
Standard-rate turn: A turn of 3° per second, a full circle in 2 minutes. Learn it →
Static port: An opening, usually on the side of the fuselage, that senses still-air pressure for the altimeter, VSI and airspeed indicator. Learn it →
Student pilot certificate: The certificate required to fly solo. Minimum age 16 for airplanes; it doesn't expire. Learn it →

T

TAF (terminal aerodrome forecast): A forecast for the area within 5 SM of an airport, usually valid for 24 or 30 hours. Learn it →
Tailwheel airplane: An airplane with a tailwheel instead of a nosewheel (conventional gear). Requires an endorsement to act as PIC. Learn it →
TFR (temporary flight restriction): A temporary restriction on flight in an area, issued by NOTAM. Learn it →
Torque: The left-rolling tendency caused by the engine turning the propeller clockwise. Learn it →
Traffic pattern: The standard path for arriving at and departing from an airport: upwind, crosswind, downwind, base and final. Learn it →
Transponder: Equipment that replies to radar with a code and, in Mode C, altitude. Inspected every 24 calendar months. Learn it →
Trim tab: A small adjustable surface that relieves control pressure so the airplane holds an attitude by itself. Learn it →
True airspeed: The airplane's actual speed through the air; indicated airspeed corrected for altitude and temperature. Learn it →
Turn coordinator: An instrument showing rate of turn and rate of roll, with an inclinometer for coordination. Learn it →

U

UNICOM: A non-government air-ground radio station, often at an FBO, that may provide airport information. Learn it →
Upwind leg: The traffic pattern leg flown straight out along the runway after takeoff, also called the departure leg. Learn it →

V

V-speeds: Standard airspeed designations such as VS0, VS1, VFE, VNO, VNE and VA. Learn it →
VA (design maneuvering speed): The speed below which the airplane will stall before exceeding its limit load. It decreases as weight decreases. Learn it →
Variation: The angle between true north and magnetic north at a location. Learn it →
VASI (visual approach slope indicator): Two bars of lights showing glide path: red over white means on path. Learn it →
Vertical axis: The axis from top to bottom through the CG. Yaw is rotation around it. Learn it →
VFE: Maximum flap extended speed: the top of the white arc. Learn it →
VFR (visual flight rules): Rules for flight in weather good enough to navigate and avoid other aircraft visually. Learn it →
VNE: Never-exceed speed: the red line on the airspeed indicator. Learn it →
VNO: Maximum structural cruising speed: the top of the green arc. Learn it →
VOR (VHF omnidirectional range): A ground navigation station transmitting 360 radials. Learn it →
VS0: Stall speed in the landing configuration: the bottom of the white arc. Learn it →
VS1: Stall speed in a specified configuration (usually clean): the bottom of the green arc. Learn it →
VSI (vertical speed indicator): A static-pressure instrument showing the rate of climb or descent in feet per minute. Learn it →

W

Wake turbulence: Wingtip vortices behind an aircraft, strongest behind heavy, clean, slow aircraft. Learn it →
Warm front: The leading edge of advancing warm air. Slow-moving with widespread stratiform clouds and steady precipitation. Learn it →
Weight and balance: The calculation that ensures an airplane's weight and CG are within limits. Learn it →
Wind shear: A sudden change in wind speed or direction, especially hazardous near the ground. Learn it →
Winds aloft forecast: A forecast of wind direction (true), speed and temperature at standard altitudes. Learn it →

Z

Zulu time (UTC): Coordinated Universal Time, used for all times in aviation weather and flight plans. Learn it →