Glossary of Terms Commonly Used When Chartering a Jet

Chartering a private jet can be a confusing business, especially when it is your first time. Below we have compiled a list of all the common terms (over 350 of them) that may arise during your time booking or renting a private jet. If you want to learn more, be sure to check out our other articles here.


Term Definition
Absolute Altitude The vertical distance of the aircraft above the ground.
Adverse Yaw When the nose of an aircraft turns away from the direction of turn.
Aeronautical Information Manual (AIM) A publication by the Federal Aviation Administration (FAA) that instructs pilots how to operate correctly in the US National Airspace System. There are separate guides for the USA and Canada. The AIM is the official guide to flight information, Air Traffic Control (ATC) procedures and aviation safety.
Air Ambulance Air charter of a private jet, helicopter or turbo-prop certified to provide air transport to medical patients.
Air Charter Act of renting or leasing a jet or plane for transport of cargo or passengers.
Air Charter Agent One who is contracted on behalf of the end user of the charter flight. A charter agent works to ensure fair market value, reasonable safety measures are followed and to provide flexibility and options for the purchaser of the air charter flight.
Air Charter Operator Responsible for the licensing, maintenance, safety and operations of the air charter company. The air charter operator is not always the owner of the luxury jet, business jet or private jet that is available for charter.
Air Traffic Control (ATC) A service operated by the authorities to ensure the safety of air traffic. Air traffic controllers in a ground-based ATC facility direct aircraft in their area during take-off, landing and while flying in the airspace.
Air Traffic Controller The service to pilots that promotes the safe, orderly and expeditious flow of air traffic. Usually each country operates its own Air Traffic Control service. In the UK, Air Traffic Control services are provided by NATS.
Aircraft The equipment used or intended to be used for flight. An aircraft is any machine that gains support or lift from the reaction of the air.
Aircraft Hourly Rate Every aircraft charges an Hourly Rate for flight time (time in the air), which makes up the bulk of most charter flight costs.
Aircraft Insurance Covers the operation of aircraft and the risks involved in aviation.
Aircraft Sourcing Standards  The Federal Aviation Administration (FAA) sets minimum standards for aircraft that can be chartered for private use under Part 135. Beyond that, some jet card providers use additional standards set by third-party auditors and organizations such as ARG/US, Wyvern and IS-BAO to guide sourcing of planes for their jet card programs.
Airfoil The shape of a surface such as a wing, blade, turbine or rotor that generates lift from air passing over it.
Airport An area that is used for takeoffs and landings of aircrafts. Airports can be on land or water.
Airshow A cabin information system that displays the aircraft's position on a moving map, with altitude, time to destination, outside temperature and other flight data.
Airspeed Speed of an aircraft relative to its surrounding air mass.
Airway Distance The actual (as opposed to straight line) distance flown by the aircraft between two points, after deviations required by Air Traffic Control and navigation along published routes.
Alternate Airport indicated on a flight plan where it is possible to divert the aircraft from its scheduled destination (in case of bad weather or any other major situation).
Alternate Airport Alternate airport is an airport that allows an aircraft to land when landing at the intended airport is not possible (typically for safety reasons).
Altimeter A cockpit instrument that measures the aircraft’s altitude. The altimeter consists of an aneroid barometer which calculates altitude based on the current air pressure.
Altitude Vertical distance between an object and mean sea level.
Altitude Indicator An instrument that details the relation of the aircraft to the horizon.
Angle Of Attack The angle made from the chord line of an airfoil and the direction of the air that strikes it.
Anhedral The downward angle or inclination of an airplane’s wing in relation to a horizontal cross-section line.
Annual Dues Some programs in addition to hourly rates and other fees have annual dues.
Annual Inspection A nose-to-tail inspection of an aircraft that is required every 12 months.
AOC An Air Operator's Certificate is the approval granted from a national aviation authority to an aircraft operator to allow it to use aircraft for commercial purposes. This requires the operator to have personnel, assets and systems in place to ensure the safety of its employees and the general public. The certificate will list the aircraft types and registrations to be used, for what purpose and in what area - specific airports or geographic region.
Applicable Aircraft Private jet card programs typically cover either specific jet types or categories such as Very Light or Small Jets, Light Jets, Midsize Jets, Super Midsize Cabin Jets, Large or Cabin or Heavy Jets, and Ultra Longhaul Jets. Additionally, some programs allow you to buy into a specific aircraft type.
Approach (Departure) Control Radar-based Air Traffic Control, associated with the tower at larger airports. Provides traffic separation services from outside the immediate airport area to a distance of about 40 miles.
Apron Hard-surfaced or paved area around a hangar. See also Ramp.
APU Auxiliary Power Unit. An onboard source of power that enables air conditioning, heating, galley facilities and cabin lighting to be used on the ground when the main engines are not operating. The APU is actually a small additional jet engine that doesn't provide any forward thrust and acts solely as a generator of electricity.
Arg/Us Gold Rated Charter Operator Requires operating certificate for at least one year, at least one turbine aircraft on certificate, in-depth historical safety analysis, and pilot background check and aircraft operational control validations.
Arg/Us Gold Rated Plus Charter Operator Requires all of the Gold Rated requirements plus an on-site audit with no safety of flight findings.
Arg/Us Level ARG/US or ARGUS provides audits of private jet operators spanning over 500 operators globally.  There are three levels:  ARGUS Gold Rated Charter Operator, ARGUS Gold Rated Plus Charter Operator, and ARGUS Platinum Rated Charter Operator.
Arg/Us Platinum Rated Charter Operator Requires all of the Gold Plus rated standards plus on-site audit with zero findings, plus functioning SMS and Emergency Response Plan.
Autogiro Or Autogyro An aircraft that is often wingless, similar to a helicopter. However, an autogiro has unpowered rotary blades that rotate due to air speed and slipstream to get air powered-lift. Also known as a gyroplane.
Avgas Aviation Gasoline. Usually followed by the octane rating. Used by piston-engined aircraft.
Aviation The operation, development, production and use of aircraft.
Avionics The electronic control systems airplanes use for flight such as communications, autopilots, and navigation.
Avionics Master Switch The switch that controls electrical power to all electronic navigation and communications equipment in the aircraft.
Avtur Aviation Turbine fuel (kerosene). Used by turboprops and jet aircraft.
Base Base of operations or a HUB for an airline. The base leg is also one of the many words describing the approach segments.
Base Leg A descending flight path that runs in the direction of landing along the runway.
Beechcraft Hawker Business jet aircraft built by Hawker Beechcraft Corporation (HBC) between 2006 and 2013.
Best Lift Over Drag Ratio Often referred to as "L over D max," this is the highest value of the ratios of lift to drag for any airfoil.
Black Box Popular name given to either the CVR or the FDR used to investigate an accident.
Black Out Days Some programs do not guarantee service on specific dates.
Blade Angle The angle between the chord of a propeller blade and a plane of rotation.
Bleed Air Compressed hot air that is produced by the operation of the engine. This is then used at high pressure for de-icing and heating the jet.
Block Flying Time Time between an aircraft first moving from its parking place for the purpose of taking off until it comes to rest on the designated parking position and until all engines are stopped.
Block Hours The advance purchase of a specific number of hours of flying time, to be flown as and when required.
Block Rates Rate for scheduling significant amounts of air charter time in advance under a prearranged agreement.
Block Speed The average speed over a specific distance "block-to block", or door-to-door with respect to the airport gate.
Boeing Business Jet A series of Boeing airliners designed for the corporate jet market and seating between 25 and 50 passengers within a luxurious configuration.
Bombardier A family of business jets.
Bombardier Global Express A large cabin, ultra long range business jet manufactured by Bombardier Aerospace in Toronto, Ontario, Canada.
Broker Many jet card providers are brokers who sourced aircraft for your trips from charter operators. These programs typically sell by cabin category, although some offer specific aircraft types.
Business Jet A smaller Commercial jet aircraft model, configured to transport smaller groups of people.
Business Jet Charter An aircraft that is chartered for the purpose or use in business transportation.
Camber The degree of curve in an airfoil.
Carbon Credit Key component of national and international emissions trading schemes. They provide a way to reduce greenhouse effect emissions on an industrial scale by capping total annual emissions and letting the market assign a monetary value to any shortfall through trading. Credits can be exchanged between businesses or bought and sold in international markets at the prevailing market price. Credits can be used to finance carbon reduction schemes between trading partners and around the world.
Carbon Emissions The principal greenhouse gas emission. Carbon is largely thought to be the most dangerous greenhouse gas.
Carbon Offset Monetary contributions to renewable energy research and production projects, designed to reflect and mitigate the user's own greenhouse gas emissions eg through air travel.
Cardinal Altitude An altitude, or flight level, of a thousand feet.
Cargo Goods carried on an airplane.
Catering A service provided for luxury jet charters. Catering is the provision of in-flight meals.
CAVU Stands for Ceiling and Visibility Unlimited, which indicates the ideal flying conditions, with a visibility of at least 10 miles and a ceiling of at least 10,000 feet.
Ceiling The heights above the earth's surface of the lowest layers of clouds or obscuring phenomena that is reported as broken, overcast, or obscuration, and not classified as thin or partial.
Cessna An American general aviation aircraft manufacturing corporation headquartered in Wichita, Kan. Known for small, piston-powered aircraft, as well as business jets.
Charter Hiring an airplane. Business and high-profile clients may often charter a private jet.
Charter Broker An individual or company that acts as a middle man between the charter operators and the charter passengers. A good broker will be able to find the best deal for his customer's needs.
Charter Card Pre-paid air charter plan, either for a block of charter hours at a pre-defined fee, or a set debit balance in dollars.
Chord Line An imaginary line on an airfoil from the leading edge to the trailing edge.
Clearance Authorization given by ATC to proceed as requested or instructed (for example: “Cleared for take-off”, “Cleared for visual approach”).
Climb A maneuver that increases the altitude of the aircraft.
Club Seating A seating layout where pairs of seats face each other, as in a railway carriage compartment, rather than all face the same way, as on a bus. The club configuration is more sociable and enables easy conversation between occupants.
Coast Track Status of an aircraft that is no longer giving a radar return. The air traffic control screen will display this status (usually with the acronym CST) and will temporarily continue displaying the aircraft’s movement at the last heading and speed, as if it was “coasting.”
Commercial Flight A "commercial" flight is when the customer has paid for a commercial charter of that aircraft. The rules for commercial flights are more stringent than private flights and include limitations on crew duty hours, runway length and other safety considerations. For commercial private jet charter the minimum stopping distance for the aircraft is multiplied by 1.6, to create the minimum landing distance required (LDR).
Commuter Operator A regional, scheduled airline. In this book limited to that operator with adequate fleet capacity as to be available of charter. Not all commuter airlines charter, because of the limitations of aircraft and crew availability.
Connection Transfer between two different flights at an intermediate airport (for example: flight 123 from New York to Miami followed by flight 456 from Miami to Sao Paulo). If a passenger’s flights are operated by two different airlines, they may check baggage or obtain boarding passes for the entire itinerary directly at the departure city’s airport, pursuant to interlining agreements or airline alliances. A connection is not the same as a stopover.
Contrails Streaks of condensed water vapour created in the air by aircraft flying at high altitudes; aka vapour trails.
Controlled Airspace A defined area of the sky that is controlled by ATC services. Controllers direct planes through the airspace, plotting the safest and most efficient route for each aircraft. All airplanes flying in controlled airspace must get clearance to enter the zone and be equipped to national regulations. The pilot must have the correct qualifications.
Corporate Operator A company flight department which has earned a "Part 135" certificate to carry passengers for compensation.
Course Deviation Indicator Also known as "CDI", this is the needle on the VOR indicator that shows whether the aircraft is to the right or left of the desired radial.
Cpi Escalator Contracts of some private jet card and prepaid programs are subject to increases based on the Consumer Price Index meaning rates are subject to increase based on CPI. In some cases, your rate will be increased on the higher of the CPI or an alternate number, meaning your rate will increase at that point.
Crew ‘Day Room’ Charges The FAA allows a crew to rest at any point to break their duty time. Putting the crew to rest during the day on a charter in order to accommodate later flight times is called ‘Day Room’. In instances where a charter requires longer time on the ground than the standard duty day (usually 12hrs) allows, the crew can be put to rest during the day in order to come back on duty later on, past the standard day cut-off. This additional rest period must last 10 consecutive hours.
Crew Duty Time The FAA has strict regulations on the number of consecutive hours a charter pilot can be on duty. The standard duty day for a crew is 14hrs total, which includes the time required to do pre and post-flight routines. The general rule of thumb for a standard duty is that the charterer can have the aircraft under their control for a maximum of 12hrs, which allows for crew to perform pre and post-flight checks.
Crew Fees Pilots are paid a base wage for flying on each charter. Pilot base pay varies by aircraft and owner, but is typically $300-$800 per crewmember.
Crosswind Winds blowing perpendicular or not parallel to the runway or the aircrafts flight path.
Cruise Speed The normal speed attained at altitude once the aircraft is no longer climbing and is en route.
Cruising Altitude A level altitude maintained by an aircraft while in flight.
Daily Minimum Flight Time Adjustments (Daily Mins) Many aircraft require the charterer to pay a daily minimum in flight charges in order to reserve. For short trips, it is often more costly for an owner to fly the airplane, pay a crew, devote operational resources to booking/payment/client service/etc. than it is to charge less than 2hrs of flight time to a customer. In order to protect the owner from losses on such trips, Daily Min fees are imposed. Daily Mins typically range from 1.5 – 2.5 hours, depending on the aircraft.
Dassault Falcon A family of business jets manufactured by Dassault Aviation.
De-Ice Charges De-ice Charges are required when an aircraft has been subjected to the winter elements while on a charter. In heavy winter weather conditions, aircraft may require a de-icing fluid to be applied to its wings. The fluid is charged by the gallon, provided by the ground crew at the airport and the pilots determines how much the aircraft needs. While de-ice Charges are impossible to predict, they can range anywhere from $100-$600 on small aircraft and up to $2,000+ on large jets.
Dead Head A leg of an air charter with no cargo or no passengers. Commonly the return leg, but may also be the repositioning.
Dead Leg See empty leg.
Dead-Heading See Repositioning.
Deadstick A term for a forced landing, which takes place when the plane loses all propulsive power because the engine and propeller have stopped.
Decision Height In an instrument approach flight, the height at which a decision must be made to either continue the approach or to execute a missed approach.
Delta Wing A triangle-shaped wing that looks similar to the shape of the uppercase Greek letter, delta. This type of wing is often used on fighter planes because of its superb aerodynamics.
Demurrage Refers to the charges that are levied by an operator when a charterer keeps an aircraft after the completion of the flight. For example, if an aircraft is chartered for two flights with a week intervening, an aircraft may remain or lay over at the destination. The charterer will pay demurrage charges for every day that this aircraft remains at the charterer’s destination without returning home.
Density Altitude Pressure altitude (as indicated by the altimeter) corrected for air temperature.
Depreciation Method to account for assets whose value decrease over time because of factors such as age, wear or market conditions.
Descent A flight maneuver that causes a downward inclination.
Destination Surcharge Some programs have surcharges for travel outside the U.S., typically when flying more than 220 miles off the U.S. coastline, but also for high-density airports, something more common in Europe. 
Direct Flight A flight that operates from point A to point B without a connection. A direct flight is not necessarily non-stop.
Distress A condition on the aircraft that signals danger and requires immediate action.
DME Distance-Measuring Equipment. A combination of ground and airborne equipment which gives a continuous slant range distance-from-station readout by measuring time-lapse of a signal transmitted by the aircraft to the station and responded back. DMEs can also provide groundspeed and time-to-station readouts by differentiation.
Double Round Trip Occurs when an air charter itinerary is designed such that it is more costly to keep the plane away from base than it would be to return home empty the report for pick up to complete the air charter itinerary.
Downwash In aeronautics, the term describes air that is deflected downwards by the aircraft wing or a rotor blade on a helicopter, usually when the plane is taking off.
Downwind One of the many words describing the approach segments.
Downwind Leg A flight path that runs parallel to the landing runway in the opposite direction of landing.
Drag A force on the aircraft as it moves through the air. The force runs parallel and opposite to the airplane's direction.
Duty Time A pilot or crew member is logging duty time whenever he is serving in any capacity. There are safety restrictions on duty time to ensure pilots and crew are sufficiently rested.
EFIS (Electronic Flight Information Systems) Glass cockpit avionics that integrate all flight parameters into one optimized instrument. These modern systems offer enhanced reliability, reduced weight, simplified installation and overall cost savings.
EGWPS (Enhanced Ground Proximity Warning System) Uses aircraft inputs such as position, attitude, air speed and glide slope, which along with internal terrain, obstacles, and airport databases predict a potential conflict between the aircraft's flight path and terrain or an obstacle.
ELT (Emergency Locator Transmitter) A radio transmitter activated automatically by the impact of an accident. Emits a warbling tone on the international emergency frequencies of 121.5 MHz, 243 MHz and (newer models) 406 MHz. ELT signals can be received by nearby FAA facilities, aircraft overhead, and search and rescue (SARSAT) satellites.
Emergency Overrun A surface before the take-off area on the runway that is kept clear. This portion is designed to minimize damage to an aircraft if it is unable to stop.
Empennage A term for the aircraft’s tail, which is made up of a rudder, a fin and a stabilizer. This is also known as the tail or tail assembly and provides stability for the jet during flight.
Empty Leg A re-positioning flight where the aircraft is flying empty. Chartering an empty leg can cost significantly less than a full-price charter.
Engine An aircraft engine is a machine that converts energy to power the plane.
Estimated Time En Route Commonly referred to as "ETE"; the estimated flight time a journey will take from departure to arrival in the destination or checkpoint.
Estimated Time Of Arrival Commonly referred to as "ETA"; the time an aircraft is predicted to arrive in its destination or checkpoint.
Executive Jet Charter An aircraft that is chartered for the purpose or use in the transportation of executives. Typically the aircrafts that are chartered are midsize jets.
Expiration Of Hours/Deposits Some programs expire hours or deposits after specific periods, typically 12 to 24 months.
FAA (Federal Aviation Administration) The US Department of Transportation's agency for aviation in the United States. In addition to regulating airports, aircraft manufacturing and parts certification, aircraft operation and pilot certification, the FAA operates Air Traffic Control, purchases and maintains navigation equipment, certifies airports and aids airport development, among other activities.
FAA Part 135 Certificate The certification required for aircraft operators to perform ‘air taxi’ services. All aircraft in the private jet charter marketplace must hold a valid FAA Part 135 certificate.
FAA Part 91 Certificate The certification required for aircraft to perform ‘owner-operated’ flights. For private aircraft owners and personnel only, flying non-commercial missions.
FBO Fixed Base Operator - provides ground services for air charter clients such as: onsite mechanic, fuel service, catering, ground transportation and other services.
Featured Charter The chartering of a specific aircraft to a specific destination. Featured charters often include hotel accommodations, luxury car rentals, golf and spa packages etc.
Federal Aviation Authority (Faa) A national authority in the United States that regulates all aspects of civil aviation.
Federal Excise Tax (Fet) Some programs include FET when marketing hourly rate, while for other programs the rate being promoted is without FET.  If you are flying within the Continental U.S. or within 220 miles of the coast and to, from or between Hawaii and Alaska the government assesses the 7.5% tax on top of your base hourly rate. As part of the CARES Act, the tax was suspended through Dec. 31, 2020.
Ferry Flight A flight for the purpose of returning an aircraft to base, delivering an aircraft from one location to another, moving an aircraft to and from a maintenance base.
Final Final Approach. One of the many words describing the approach segments. The part of a landing sequence or aerodrome circuit procedure in which the aircraft has made its final turn and is inbound to the active runway.
Final Approach A flight path that leads towards the landing runway.
Fixed Base Operator (Fbo) A business or organization that operates at an airport. An FBO provides aircraft operating services like maintenance, fueling, flight training, charter services, hangaring and parking.
Fixed One-Way Rates Fixed One-Way Rates mean that you won’t have to pay for ferry fees to reposition your aircraft either before or after your flights within your Primary Service Area. By choosing a program with fixed one-way rates you can more accurately budget how much your private flying will cost in advance. 
Flaperon A control surface that uses aspects of both flaps and ailerons, such as on the wing, to direct the roll or bank of a plane.
Flaps Flat surfaces added to the edges of the wing. These change the curve of the wing and allow the pilot to adjust lift and drag so the plane can safely fly at a lower speed.
Fleet Manager A commercial aviation entity developed to subcontract the maintenance and operation of corporate aircraft, which are often chartered out to the general public.
Flight Attendant A member of the crew dedicated to attending to the passengers during the flight. Often able to meet advance requests for specific catering, drinks, magazines, flowers or other requirements.
Flight Attendant Inclusion  Some programs provide flight attendants on specific aircraft types
Flight Cancellation Deadline Cancellation policies refer to the lead-time in which you can cancel your flight without penalty. Lead times can vary based on peak and non-peak periods as well as for domestic versus international flights.
Flight Deck Another name for the cockpit, which is located at the front of the aircraft and holds the pilot and instrument panels.
Flight Plan Filed with an Air Traffic Control Facility a flight plan is the specific information regarding the flight or intended flight of an aircraft.
Flight Time The time between take-off and landing. Excludes any time spent taxiing to and from the stand.
Fms (Flight Management System) A regional office of the United States Federal Aviation Administration that concentrates on enforcing regulations.
Fod Foreign object debris. FOD refers to anything on the runway that may cause hazards to aircrafts or people on the ground.
Fractional Fleet Some jet card providers use aircraft from their fractional lease and ownership programs to sell jet cards. These programs are more likely to enable you to choose a specific aircraft type as opposed to broker programs, which more typically sell by category. 
Fractional Ownership The purchase of a "share" of an aircraft. Fractional owners are guaranteed access to an aircraft but not necessarily the same one each time. They usually pay a fixed monthly maintenance fee as well as an hourly fee.
Freedom Of The Air Commercial aviation right governing carriage of PAYLOAD between or within countries.
Fuel Surcharge During periods of fuel price increases, some programs reserve the right to impose fuel surcharges. Others have fuel surcharges as part of their normal pricing. Fuel surcharges are typically updated monthly or quarterly.
Fuselage An aircraft's main body structure housing the flight crew, passengers, and cargo.
GAT Abbreviation for General Aviation Terminal. The Handling Agents will often be located here as GA terminals are much quieter than scheduled terminals.
General Aviation The aviation industry categorises flights as either Scheduled, Cargo, Military or General. Non-airline passenger flights fall in the broad General Aviation category, however the terms Business Aviation or Executive Aviation are frequently used to differentiate private jet charter flights from light aircraft enthusiast flights.
Global Positioning System (GPS). Satellite positioning, velocity and time system. Highly accurate navigation aid.
Go-Around Balked approach, when the aircraft climbs away from the runway during the approach, to either start the approach again, or proceed to the ALTERNATE AIRPORT.
GPWS (Ground Proximity Warning System) System designed to alert pilots if their aircraft is in immediate danger of flying into the ground. Also called Ground-Collision Warning System.
Great Circle Distance The shortest distance between two points on a globe. All distances shown in distance tables in the Air Charter Guide are "great circle distance".
Ground Control The personnel and equipment in a control tower who are responsible for the safe and efficient movement of aircraft on the ground.
Ground Speed The speed of an aircraft relative to the surface of the earth.
Ground Transportation A service provided for luxury jet charters before or after the flight. Ground transportation can be limo service or luxury car rental.
Groundspeed The horizontal speed that an aircraft travels over the ground.
Guaranteed Availability Guaranteed availability refers to the window in your contract you can call your provider and they will get you an aircraft. Providers that also give you a fixed-rate typically require six to 48 hours lead time, and longer during Peak Day periods. Guaranteed availability and fixed one-way rates are considered two key benefits of a Jet Card vs. On-Demand Charter.
Guaranteed Downgrade Guaranteed downgrades enable you to trade down from your program jet type or size to a smaller jet. This can save money if you are for example traveling alone on a shorter flight and want a smaller plane to save money on your hourly rate.
Guaranteed Upgrade Guaranteed upgrades enable you to reserve a larger aircraft than the program you bought. This is useful if you are traveling with a larger group or need a longer ranger plane. Some programs such as NetJets only guarantee downgrades and make upgrades in aircraft size as available. 
Gulfstream Business jet aircraft designed and manufactured by Gulfstream Aerospace Corporation, a wholly owned subsidiary of General Dynamics. Gulfstream’s fleet consists of these models: G150, G280, G350, G450, G500, G550, and G650.
Handling Agent A company appointed by the operator to greet and ease their passengers' passage through an airport. Will typically feature a dedicated car park, VIP lounge, security and immigration liaison and baggage porterage.
Hangar An enclosed structure for housing aircraft. Originated with lake-based floating homes of the original German Zeppelins in which they were "hung" from cables.
Heavy Suffix used in radio transmission callsigns (for example: “United 492 Heavy”) to indicate the aircraft is capable of generating WAKE TURBULENCE.
Heavy Crew Flying with one or more additional flight crew members. On occasion an ultra-long range aircraft might carry additional pilots to allow each to rest in rotation and counter the onset of fatigue.
Heavy Jet An aircraft with a minimum takeoff weight of 255,000 lbs.
Helicopter A rotor driven aircraft that uses vertical axes with pitched blades to generate lift and stability.
Helipad Used by helicopters for takeoffs, landings and occasionally for parking.
Heliport The area of land or water used for the landings and takeoffs of helicopters, the buildings, structures and grounds.
Holding Pattern Maneuver consisting of making the aircraft turn around the aerodrome at an assigned altitude, while awaiting further ATC instructions.
Horizontal Stabilizer A small lifting surface on the tail of an aircraft, also known as the tailplane, that provides stability.
Horse Power The motive energy required to raise 550 lbs. one foot in one second, friction disregarded.
Hourly Rate Hourly rate is the rate per hour your program charges. Hours are typically broken down by 6, 10, or 12-minute increments and rounded up.
IATA Code International aviation codes for international airports
ICAO (International Civil Aviation Organization) An agency of the United Nations. The IACO is charged with the development of principles and techniques of international air navigation.
Included Catering Most programs include basic catering which might include non-alcoholic beverages and snacks. Some programs include more substantial catering such as sandwiches, fruit plates, hot meals, gourmet preparation, alcoholic beverages, or credits. All programs allow you to order for an additional charge catering to meet your needs.
Indicated Air Speed The speed displayed by the aircraft's air speed indicator device.
Initiation Fee Some jet-card programs have a one-time initiation fee.
Instrument Approach An airport installation that enables the aircraft to safely land in poor visibility. All commercial airports and all but the smallest general aviation aerodromes have at least one instrument approach. A private jet charter can be arranged to any licensed airport or aerodrome with a runway sufficient for the aircraft.
Instrument Flight Rules (IFR) The rules that govern flying under instrument meteorological conditions. Pilots follow these rules and create IFR flight plans for various weather conditions.
Instrument Landing System (ILS) A radar-based system which allows ILS-equipped aircraft to find a runway and land safely, even when clouds are as low as 200 feet.
Instrument Meterological Conditions Conditions such as visibility, distance between clouds, ceiling level that does not meet the standard for visual meteorological conditions.
Interchange Fees Interchange fees are additional fees charged if you upgrade or downgrade the size of your jet or go between two service areas in a program, for example, North America and Europe.
International Airport Any airport designated by its contracting state to carry out the duties of customs and immigrations along with other duties.
Jet Airliner An airliner that uses jet engine propulsion. Capable of efficiently functioning at a high altitudes and high speeds.
Jet Cards Schemes by which operators sell individuals block hours on their aircraft.
Jet Charter Act of hiring crew; leasing an aircraft for the purpose of private air transportation.
Jet Charter Broker An intermediary who facilitates the leasing or purchasing of air charter. See also Private Jet Broker.
Jet Engine An internal combustion air-breathing duct engine.
Jet Stream High altitude, High Speed winds that in the United States blow from west to east.
Joint Ownership Purchase or lease of a complete aircraft by a relatively small number of owners, often through a partnership or limited liability corporation.
Joystick Also known as the control column, the joystick is the main device in the cockpit for controlling the aircraft. The joystick is usually floor- or roof-mounted.
Knot A measurement or unit of speed that equals one nautical mile and about 1.15 statute miles.
Knot (Kt) Standard unit of speed in aviation and marine transportation, equivalent to one nautical mile per hour. One knot equals 1.1515 mph, and one nautical mile equals 6,080 feet. The word “knot” replaces “nautical miles per hour.”
Landing Fees Landing Fees are paid to the airport you fly into and will vary by location. Major metro airports like Los Angeles International (LAX) and Miami International (MIA) are considerably more expensive to land in than smaller, rural airports. Landing Fees can range from $100 – $2,500, depending on the airport.
Landing Gear The undercarriage of an aircraft. This structure supports the plane when it’s not flying and is used during taxi, lift-off and landing.
Lavatory Type Not all aircraft have fully enclosed lavatories or lavatories you can stand up in. For longer flights or personal preference, you should ask for pictures of the lavatories on the aircraft types that will be part of your program. Not all light and very light jets have full lavatories. 
Layover A rest stop away from home base for the aircraft and crew in the middle of a flight.
Learjet A private luxury business jet aircraft originally manufactured by Learjet in Wichita, Kan. Now owned by Bombardier. The word is also used generically to refer to small business jets.
Leg A single direction of travel between two points. For an air charter itinerary a leg could be represented by repositioning and fuel stops.
Level Flight A flight maneuver that causes the aircraft to stay at the same altitude.
Liability And Risk Coverage (Insurance) Programs provide varying amounts of liability and risk coverage.
Lift The aerodynamic force acting on an airplane that runs perpendicular to the relative wind. Lift causes the upward force that allows the aircraft to oppose gravity.
Lighter-Than-Air Craft (Lta Craft) Refers to things like blimps, dirigibles and free balloons that float.
Loc Localizer. The azimuth guidance portion of an instrument landing system.
Longitudinal Axis A direction of orientation; an imaginary line that passes horizontally through the center of gravity, from the head to tail of an aircraft.
Loran Long-Range low-frequency Radio Navigation. Its range is about 1,200 nm by day, and 2,300 nm by night.
Lrops Long Range Operational Performance Standards. Certification intended to replace ETOPS as it would include all types of aircraft (not just twin-engine).
Mach Number Ratio of true airspeed to the speed of sound. Mach 1 is the speed of sound at sea level. Its value is approximately 760 mph.
Magnetic Compass A liquid-type compass and essential navigation instrument that displays an aircraft’s orientation in relation to the magnetic poles.
Magnetic Course Intended horizontal direction, measured in degrees clockwise from the magnetic north.
Managed Fleet Some jet card providers use aircraft they manage for individual owners to sell jet cards. Like a broker-based jet card program, Managed Fleet jet cards typically sell by size category as they have a variety of aircraft types in each category, meaning you are likely to get a different jet type per trip.
Maneuvering Speed A speed calculated by the aircraft manufacturer that keeps the user from exceeding the maximum load factor for the airplane.
Manufacturer Aircraft builder, such as Airbus, Boeing, Embraer, etc.
Master Switch The switch that controls power to all electrical circuits in an aircraft.
Match Speed The ratio of ones true airspeed to the speed of sound
Mayday The ultimate international radio distress call, indicating imminent danger to the life of the occupants onboard and requiring immediate assistance.
Mean Sea Level (Msl) The average height of the surface of the sea. MSL is used in aviation to measure altitude.
Medevac Medical evacuation - the term commonly applied to an aircraft used to transport injured patients to hospital. See also Air Ambulance.
Medevac (Medical Evacuation) the term commonly applied to an aircraft used to transport injured patients to hospital. See also Air Ambulance.
Mid-Size Jets Aircraft designed for longer-range travel such as transcontinental flights. Provide larger passenger capacity.
Minimum Flight Time Charged Different programs have minimum times charged, so a 40-minute flight might be charged as one hour of program time if that is the minimum. If you will be taking a lot of short flights, you will want to pay attention to this. Also, some programs charge a daily minimum. Minimums are typically one to two hours and can depend on the size of the plane. If you multiple same-day short hops, a program with only a daily minimum may be advantageous. 
Minimum Seating As you select a vendor and program you should think about the number of people, including children, you will be traveling with so that the majority of your missions can be accommodated by the type of planes used in the program you are buying. Within a category, a provider might offer aircraft between six and eight seats, so if you typically travel with seven people, that may mean you need to choose a larger cabin program to ensure your needs will be met. 
MTOW Maximum Take-Off Weight.
Multiple Same Time Aircraft Access This allows you to use two or more planes from a single program at the same time.
N Number The registration number on a US-registered plane. The letter N is the letter internationally used to identify a US plane.
NARA National Aircraft Resale Association.
National Airspace System National Airspace System is the network of airspace, navigational services facilities and equipment.
NATS Provider of Air Traffic Control services to aircraft flying in UK airspace and over the eastern part of the North Atlantic.
Nautical Mile Used to measure distances at sea. 2,025 yards or 6,076 feet.
Navaid Stands for Navigational Aid, a device in an aircraft used to help with navigation.
Navaids Navigational aid is any form of device that guides a pilot and his aircraft from one area to another. There are many different kinds of Navaids in use to provide guidance, location, and direction, the most popular being the Global Positioning System (GPS) but the term can also apply to a map, a beacon or a compass.
Navigation Recording, planning and controlling the movement of an aircraft from one point to another.
NBAA National Business Aviation Association.
Nm Nautical Miles.
No-Show Passenger with a confirmed reservation, who failed to check-in or board on time.
Non-Revenue Passenger flying free of charge, on a STANDBY basis, by presenting an airline/aviation employee pass. Non-Revenue passengers may or may not be on duty, therefore this expression also applies to repositioning crew members. Also known as Non-Rev for short.
Non-Stop A direct flight that operates from point A to point B without a stopover.
Non-Towered Airport An airport without a control tower.
Nontowered Airport An airport without a control tower
NTSB National Transportation Safety Board. A United States government organization in charge of investigating in the case of an accident. In many countries, an AAIB fulfills that role.
Oil Pressure Gauge An instrument in the aircraft that shows the pressure of the lubricating oil in the engine.
One-Way Surcharge Charter pricing for one-way flights is typically more expensive than roundtrip flights on a per leg basis as it entails flying the plane to or from as an empty leg in which the operator incurs costs but doesn’t generate revenue, so you have to pay. Many jet card and prepaid programs do not have one-way surcharges giving you extra flexibility, however they will offer roundtrip discounts.
One-Ways The air charter of an aircraft for a particular leg of an existing air charter itinerary.
Operating Limitations Indicates limits for a specific aircraft’s speed, weight, pressure, and passenger and crew size. The limits are determined by the aircraft manufacturer.
Operator Responsible for the licensing, maintenance, safety and operations of one or more private charter aircraft. The operator is not always the owner of the luxury jet, business jet or private jet that is available for charter.
Overnight Fees Overnight Fees are assessed when an aircraft and crew are kept at a location overnight, and typically include hotels for the pilots and hangar fees for the airplane. Crew overnight costs are typically $600 – $1000 per day, per pilot. Hangar Fees vary by airport.
Owned Fleet Some jet card providers own the aircraft they use to sell time for their jet cards. These programs are more likely to enable you to choose a specific aircraft type as opposed to broker programs, which more typically sell by category. 
Pan Pan International radio urgency call. It usually indicates a threat to the safety of an aircraft or its passengers. It is, however, less urgent than Mayday. Pan Pan comes from the French word “Panne” which means “failure.”
Part 135 The U.S. government regulations and rules that all domestic private jet operators providing on-demand charter and jet card flights operate.
Pattern The path of aircraft traffic around an airfield, at an established height and direction. At tower-controlled fields, Air Traffic Controllers supervise the pattern by radio (or in non-radio or emergency conditions by red and green light signals.
Pax Passengers.
Payload Anything that an aircraft carries beyond what is required for its operation during flight, theoretically cargo or passengers from which revenue is derived.
Peak Day Surcharge Most programs have surcharges for peak travel days. The number of peak days vary by program as do the surcharge. If you are buying a jet card in anticipation of flying during busy holiday periods and aren’t flexible to move your dates, you should study any peak travel surcharges or blackout dates. Surcharges range up to 40%.
Pet Policy Most programs allow you to take certain types of pets. Some programs have mandatory or discretionary cleaning fees. If you are using a broker or managed fleet program it pays to triple check their policy since they don’t have the final say on pet policies
Phonetic Alphabet Spelling technique under which each letter is replaced by a word starting with the letter in question (for example: Alpha, Bravo, Charlie to spell “ABC”). The current alphabet is also known as the ICAO spelling alphabet, the international radiotelephony spelling alphabet or the NATO phonetic alphabet.
Pilot Experience Jet card companies have different standards and minimums for pilot experience above government requirements, typically both for Captain and First Officer, and also by total hours of flight time and type in the type of aircraft they will be flying you.
Pilot In Command (PIC) The pilot responsible for the safety and operation of the plane for the duration of the flight.
Pitch A motion on an aircraft's lateral axis (which runs from wing to wing) that causes the forward end to rise or fall.
Point To Point Pricing Usually occurs when one charters a jet from a location other than where that aircraft is based; also known as a transient aircraft charter. Point to point pricing is typically the result of an empty leg being chartered for a portion of the primary routing of the original air charter itinerary.
Positioning When aircraft is ferried from its originating airport to another airport for departure.
Positioning Flight To fly an aircraft empty to a particular airport in order for it to be able to commence a flight from that airport.
Precipitation Water particles that fall from the atmosphere and reach the surface of the earth.
Preffered Vendors Air Charter Agents, Jet Charter Brokers and Charter Jet Operators develop a list of Air Charter vendors for each region that they service. Preferred vendors are the vendor of choice for supplemental lift.
Preignition Ignition that takes place in an internal combustion engine before the usual ignition occurs.
Primary Flight Display Also called "PDF", this is the electronic display screen that indicates the horizon, altitude, airspeed, vertical speed, rate of turn, trend and more.
Private Airport An airport used by general aviation and private aviation but is ineligible for use by scheduled airline travel.
Private Flight A "private" flight is when an owner of the aircraft (or one of their friends or family) are using the aircraft for private use. No money changes hands for the use of the aircraft. (As opposed to a commercial flight)
Private Jet An aircraft that is privately owned.
Private Jet Broker An intermediary who compares options from operators to facilitate selling or buying a private aircraft.
Private Jet Charter Hiring a private jet aircraft for a specific itinerary - as opposed to ownership or fractional ownership of an aircraft.
Program Dollar Denominations Jet card programs are generally denominated in dollars, for example, $25,000, $50,000, $100,000, $250,000 or $500,000 or hours. The higher the dollar value of the program you buy, the lower your hourly rate.
Program Hours Denominations Jet card programs are generally denominated in hours, for example, 10, 15, 25, 50 or 100 hours or dollars. The more hours you buy, typically, the lower your hourly rate.
Prohibited Area An airspace area where flight is prohibited except by prior arrangement with the controlling agency.
Propeller A rotating piece powered by the engine that produces thrust to propel the airplane through the air.
Quadraplane A type of aircraft that has four or more wings of similar spans, also known as quadruplanes.
Radar Transmission of a radio pulse that provides information on range and elevation of objects in the path of transmitted pulses.
Radar Approach Control Facility (Rapcon) A facility based in an airport terminal that uses both non-radar and radar to provide services for planes that are moving through a controlled airspace, landing, or taking off. RAPCONs commonly operate near civil and military airports and may be controlled by the FAA, military or both.
Radio A device used by aircraft for the purpose of communication.
Ramp The apron or open "tarmac" in front of an FBO or terminal facility. This space is busy, used for deplaning, parking of aircraft, etc.
Refill Policy Refill policy refers to enabling you to add money or hours to an existing program you purchased at the original terms.
Refund Policy Some programs will refund unused funds while others will not and others will allow you to roll it over to a new program. If you are unsure you are going to use all your hours or funds, you will want to pay attention to Refund Policy.
Registration Number The number assigned to an aircraft by the government for purposes of identification. The number must be displayed on the exterior of the aircraft so it is visible.
Release Time A departure time restriction issued to a pilot by ATC (either directly or through an authorized relay) when necessary to separate a departing aircraft from other traffic.
Reposition To undertake a positioning flight.
Repositioning Flying from the point of destination to the next point of origin, without carrying any PAYLOAD (in the case of an aircraft) or without being responsible for payload (in the case of a crew member). Example: a scheduled U.S. airline operates a charter flight from Los Angeles to Lisbon. Then, payload-free, it flies to Paris, where it will board passengers and cargo for a scheduled flight back to Los Angeles. Also known as deadheading, ferry flight.
Repositioning Fees Repositioning fees are flight time charges related to flying an airplane to or from a destination in order to facilitate a charter. As the charterer, if you are booking a flight from a destination that has no aircraft on location, you will often pay to fly a plane in to pick you up. In addition, when dropped at your destination you are also often responsible for flying the plane back to its base. Repositioning fees are sometimes discounted, but are typically price the same as the Base Hourly Rate of the aircraft.
Repositioning Time The travel time for charter aircraft traveling to or from base en- route to the departure or from the destination of the particular air charter trip.
Reservation Lead Time Different programs require lead times that can range up to 48 hours to reserve your flight. Lead times can be longer during peak periods or for international flights. Lead time for programs that have fixed rate pricing tends to be longer, but starts as low as six hours. 
Restricted Area “Active” or “Hot” airspace that usually excludes civilian aircraft. May include airspace used for rocket flights, practice air-to-air combat or ground-based artillery practice. Temporary restricted areas are established for forest fires, natural disasters or major news stories. Flight through a restricted area may be authorized by the FAA.
Revenue Flight Any flight that generates revenue for the operator. i.e. not a positioning, crew training or maintenance flight.
Roll Motion on an aircraft along its nose-to-tail axis.
Roundtrip Discount  Since roundtrip flying is more efficient for the operator, jet cards typically offer discounted roundtrip rates. Published discounts range up to 40% so if you are making qualifying roundtrip discounts it is something worth researching. 
Roundtrip Qualification What qualifies for a roundtrip flight in private aviation varies, but typically it is a period where your trip is short enough that the plane that flies you out can wait for you and fly your back thus eliminating empty leg (non-revenue) flights. Usually, it means at least two billable hours on a single day starting and returning to the same airport or at least two billable hours on consecutive days. To achieve a roundtrip discount you may have to complete all your day’s flights within 14 hours to comply with crew duty time limits
Rudder Aircraft control surface attached to the rear of the vertical stabilizer (fin) of the aircraft tail. Forces the tail left or right, correspondingly "yawing" the aircraft right or left. Rudder movement "coordinates" with the banking of wings to balance a turn. Controlled by left and right rudder (foot) pedals.
Runway Smooth area prepared for landings and takeoffs of aircrafts.
Scheduled Air Transportation Airline Transportation regulation for scheduled air service requiring the FAA Part 121 certificate.
Sector Segment involving a take-off and landing (for example: a London-Bangkok-Sydney flight contains two sectors).
See And Avoid The FAA requirement that all pilots are ultimately responsible for separation from other aircraft when visual conditions permit spotting traffic. Even IFR flights when operating in visual weather conditions or VFR flights being issued radar advisories are responsible for visual scanning to see-and-avoid other traffic.
Segment Fees Segment Fees are paid to the IRS on a per-passenger basis for each leg of every trip. Domestic flights are $4 per passenger. International Segment Fees are $17.50 per passenger.
Service Area (Primary Service Area) Some programs enable you to travel globally while others will only fly you in a limited area, typically North America and parts of the Caribbean, Mexico or possibly Hawaii. Some service areas aren’t country specific, but refer to a mileage limit outside of the Continental U.S. border. If you plan to use your jet card flying to Mexico or the Caribbean, for example, make sure the place you are flying is within the service area of the program you are buying as rates may vary.
Service Recovery Outside of weather, different programs have different commitments for mechanical delays, pilots running out of flight hours, etc. This is another benefit compared to on-demand charter. 
Short Field A short runway length at the airport that requires a pilot to take off or land an aircraft within the shortest possible distance.
Short Leg Fees Short Leg Fees are assessed when an aircraft is made to fly for a very short distance (anywhere from 10 to 90 minutes, depending on the aircraft). Flying a plane up in the air and back down again is called a ‘cycle’ in aviation. With each cycle, the plane’s value effectively decreases due to wear and tear on the engines and various insurance and maintenance triggers. Repositioning a plane from its home base to a nearby location in order to pick up passengers will often result in Short Leg fees, in order to compensate the owner for the loss in value to his aircraft without sufficient air time charges. Short Leg Fees are almost exclusively seen in jet charters (not turboprops) and can range from $200-$500 per instance.
Sigmet An advisory issued in times of severe weather that is significant to the safety of ALL aircraft.
Single Engine An aircraft with just one engine. Single-engined jets include light aircraft such as Cessnas.
Small Cabin Jets Private jets built primarily for efficiency and lower cost of operation. A good choice for business travel and still afford plenty of luxury on shorter journeys.
SOB Souls (persons) On Board. Also POB, Persons on Board.
Soft Field An unpaved airport runway typically comprised of grass or dirt.
Speed Of Sound Equal to 761 mph at sea level. Also known as Mach 1.
Sport Jet Charter The chartering of an aircraft for the purpose of transporting members of sports teams to sporting events.
Squawk A four-digit number assigned to an aircraft. The pilot can use this number to identify his or her plane when contacting ATC.
Stage Length The distance of the air charter client's itinerary.
Stall An aircraft condition when the angle of attack is so great that the air no longer flows easily over the airfoil.
Stand The part of the tarmac on which the aeroplanes stand when idle, separate from the taxiways and runways. Many airports allow private charter customers’ cars to be escorted to and from the stand for transferring passengers and luggage. If preferred, or where airport regulations prohibit passenger vehicles airside, the handling agent will transfer passengers and luggage in their own vehicles.
Stand-Up Cabin A cabin designed for sufficient height to allow passengers to move around the cabin with relative ease. Typically taken to be a ceiling height of 5'8" or greater.
Standby In radio communications, is a word to ask the other person to wait for further instructions. A standby reservation is conditional and is on a waiting list, in case of any NO-SHOWS.
Statute Mile A unit of length equal to 5,280 feet.
STOL Short Take-Off and Landing.
Stopover Scheduled interruption of a flight at an intermediate airport, either to refuel (in which case, it is known as a “technical stopover”) or to pick up/drop off PAYLOAD (for example: flight 789 from New York to Delhi, with a stopover in London). Unlike a connection, a stopover usually does not involve a change of flight number or airline, but may involve a change of aircraft.
STOVL Short Take-Off and Vertical Landing.
Straight Flight The flight maneuver that causes the aircraft to maintain the same direction.
Super Mid-Size Jets Combining transatlantic capability with the speed and comfort of a wide-body, high-altitude aircraft. Feature wide-body cabin space, high-altitude capability, speed and ultra-long range.
Tail The aerodynamic surfaces located at the rear of an aircraft.
Tail Number An airplane's registration number.
Tail Wind Winds that are more than 90 degrees to the longitudinal axis of the runway.
Tarmac An airport surface paved with the substance, especially a runway or an apron at a hangar.
TAWS (Terrain Awareness and Warning System) An advanced type of GPWS that provides the flight crew earlier aural and visual warning of impending terrain, forward looking capability and continued operation in the landing configuration.
Taxi Time The time the aircraft takes taxiing from the stand to runway on departure and from the runway to the stand on landing. Typically totals around 10 minutes per leg.
Taxi Time Billing You will typically be charged for taxi time, generally 12 minutes per segment, which means if your hourly rate is $8,000 per hour, your account will be charged $1,600 per segment for taxi time. Not all programs charge for taxi time.
TCA (Terminal Control Area) A volume of controlled airspace set up at the confluence of airways in the vicinity of one or more major airports to protect traffic climbing out from and descending into the airports.
TCAD A proprietary low cost anti-collision system detecting and alerting pilots to nearby transponders but not providing evasive instructions or coordination with other aircraft.
TCAS Traffic alert and Collision Avoidance System. U.S. developed radar-based airborne collision avoidance system operating independently of ground-based equipment. TCAS-I generates traffic advisories only, TCAS-II provides advisories and collision avoidance instructions in the vertical plane.
Technical Stop Landing at an airport en-route to the destination airport for technical rather than operational reasons, most typically to upload fuel if the total journey exceeds the range of the aircraft.
Third Party Verification Refers to the verification of safety, maintenance and operations by an independent auditor.
Threshold The portion of a runway that is available for landing.
Throttle A valve in the carburetor that controls the amount of fuel that can enter the engine.
Thrust An aerodynamic force produced by a propeller or engine that pushes an aircraft forward.
Toga Take-off/Go Around. An autopilot setting activating take-off or GO-AROUND thrust.
Torque A force that aims to produce rotation.
Touchdown Synonym of landing. May also refer to a stopover that does not involve a change of aircraft or flight.
Tower A radio call sign used to reach the local controller.
Traffic Pattern A standard rectangular flight pattern around the landing runway at an airport. Includes 45-degree or crosswind entry to the rectangle, with downwind, base and final legs as sides of the rectangle. Standard are 90-degree left turns around the rectangle (non-standard right-hand traffic pattern is noted in Airport Facility Directories) with downwind flown at a specified altitude, usually 1,000 or 1,500 feet above the airport elevation. At airports with a control tower; the pattern may be modified or short-cut according to ATC instructions.
Transition Altitude (Ta) Altitude in the vicinity of an aerodrome at or below which the vertical position of an aircraft is controlled by reference to altitude (with the aerodrome QNH set on its altimeter). Above transition altitude QNE is set and flight levels used. Also called transition level (TL) at which a descending aircraft changes from FL to QNH.
Transponder Airborne receiver/transmitter portion of the SSR system which receives the interrogation signal from the ground and automatically replies according to mode and code selected. Modes A and B are used for identification, using a four-digit number allocated by air traffic control. Mode C gives automatic altitude readout from an encoding altimeter.
True Airspeed Also called "TAS"; the speed of an aircraft as it moves through the air. The number is corrected to account for temperature and altitude.
True Altitude The distance of an aircraft above sea level. This is represented in Mean Sea Level.
Turbine Engine that uses compressed air to generate thrust to spin a metal shaft inside the motor. Turbines are vital components in jet engines and also power turboprop aircraft.
Turbo Jet Aircrafts Aircrafts with jet engines that operate turbines which operate air compressors.
Turbo Prop Aircraft An aircraft with turbine and propeller powered by a jet engine.
Turbosuperchargers A turbine-driven forced induction device, also known as a turbocharger. It increases the power and efficiency of a combustion engine and is used in aviation and ground vehicles.
UM Unaccompanied Minor. Underage passenger (typically 5-15 years old) travelling without a parent, guardian or trusted adult. An UM is under the constant supervision of airline staff from the departure gate until he or she is picked up at the arrival airport.
Unaccompanied Minor Travel Policy Age limits for sending an unaccompanied minor privately on your program range from minimums of 5 to 18 years old, although some programs don’t have minimums. In some cases, you will need to pay additional fees for a flight attendant to accompany your child.
Unicom (universal communication) A common radio frequency (usually 121.0 mHz) used at controlled (non-tower) airports for local pilot communication. UNICOM is also used by a Fixed Base Operator for general administrative uses, including fuel orders, parking instructions, etc.
Upwind Leg A flight path that runs parallel to the landing runway in the same direction as landing.
Urgent Condition A potential distress scenario that requires assistance, though not necessarily immediate.
UTC Greenwich Mean Time (GMT). The abbreviation is a compromise between the French language term Temps Universel Co-ordonné and the English language equivalent Universal Co-ordinated Time.
V/Stol Vertical and Short Take-Off and Landing.
Vertical Speed Indicator (Vsi) A panel instrument that measures the rate of climb or descent in feet-per-minute, by sensing the change in atmospheric pressure. The VSI is also known as a variometer.
Very High Frequency Omnidirectional Range Also called "VOR", this is a short-range radio navigation system that allows aircraft to determine their position and receive radio signals from beacons on the ground.
Vfr Visual flight rating; does not allow pilots to ascend through cloud cover.
Visibility The ability to see and identify prominent un-lit objects during the day and lit objects of prominence at night.
Visual Meterological Conditions Conditions such as visibility, distance between clouds and a ceiling that is equal to or better than the specified minimums.
VLJ Very Light Jet (may also be referred to as entry-level jet) is a small, short-range and jet that can be operated by a single pilot and seats 2-4 passengers.
Wait Time The time the aircraft is waiting on the tarmac for the departure of its next leg of the itinerary.
Waiting Time The time that the crew and aircraft must spend on the ground waiting for passengers to return to the airport on a multi-leg trip.
Wake Turbulence Turbulent air condition caused by small, tornado-like horizontal whirlwinds trailing an aircraft's wingtips (wingtip vortices). Wake turbulence associated with larger aircraft flying at slow speeds (as on take-off or landing approach) is the most severe and can cause loss of control for smaller aircraft following close behind. Controllers use defined separation standards to avoid the problem for take-off, landing, approach and departure operations.
Waypoint Reference point used for navigation, usually indicated by latitude and longitude and sometimes altitude and typically used for GPS and INS navigation.
Weather Minimums The lowest or worst visibility conditions an aircraft may be legally flown under visual flight rules. Aircraft are required to fly under instrument flight rules, or not at all, when visibility is less than the specified minimums.
Weight-Shift-Control A method of steering an aircraft such as a hand glider or paraglider. The pilot uses their weight to steer the craft, pushing against a triangular control bar that’s attached to the wing structure.
Wind Shear A quick change in wind speed or wind direction at any angle.
Windshear localized change in wind speed and/or direction over a short distance, resulting in a tearing or shearing effect, usually at low altitude, that can cause a sudden loss of airspeed with occasionally disastrous results if encountered when taking-off or landing.
Wing The piece of a heavier-than-air aircraft that creates aerodynamic lift.
Wing Walker An employee on the ground who assists the aircraft by walking on the wings to ensure there is ample space for clearance.
Winglet A small, stabilizing, rudder-like addition to the tips of a wing to control or employ air movement, thereby increasing fuel economy.
Wyvern Wingman Wyvern Wingman is a third-party rating system of private aircraft operators measuring adherence to ICAO (International Civil Aviation Organization) standards for safety management systems, emergency response plans, and internal evaluations. Included is a two-day, on-site audit recurring every 24 months.
Yaw The side-to-side movement of an aircraft on its vertical axis.
Yoke The control wheel of an aircraft, similar to a car steering wheel.
Zulu Time UTC or Greenwich Mean Time (GMT). The aviation convention is to append the characters Z to times written as UTC and L to times written as local time. In the phonetic alphabet, Z is pronounced Zulu.