Glossary   A - E

Aborted takeoff   To terminate a planned takeoff when it is determined that some condition exists which makes takeoff or further flight dangerous

Above ground level (AGL)   The actual height above ground level (AGL) at which the aircraft is flying

Acceleration   Force involved in overcoming inertia, and which may be defined as a change in velocity per unit of time

AD   See Airworthiness Directive

ADM   See aeronautical decision-making

Adverse yaw   A flight condition at the beginning of a turn in which the nose of the aircraft starts to move in the direction opposite the direction the turn is being made, caused by the induced drag produced by the downward-deflected tip holding back the wing as it begins to rise

Aerodynamics   The science of the action of air on an object, and with the motion of air on other gases Aerodynamics deals with the production of lift by the aircraft, the relative wind, and the atmosphere

Aeronautical chart   A map used in air navigation containing all or part of the following: topographic features, hazards and obstructions, navigation aids, navigation routes, designated airspace, and airports See also Sectional Chart

Aeronautical decision-making (ADM)   A systematic approach to the mental process used by pilots to consistently determine the best course of action in response to a given set of circumstances

A/FD   See airport/facility directory

AFM   See aircraft flight manual

AFSS   See automated flight service station

Aircraft   A device that is used or intended to be used for flight in the air

Aircraft accident   An occurrence associated with the operation of an aircraft that takes place between the time any person boards the aircraft with the intention of flight and all such persons have disembarked, and in which any person suffers death or serious injury or in which the aircraft receives substantial damage (NTSB 830 2)

Aircraft categories   (1) As used with respect to the certification, ratings, privileges, and limitations of airmen, means a broad classification of aircraft Examples include: powered parachute, airplane, rotorcraft, glider, lighter-thanair, and weight-shift control (2) As used with respect to the certification of aircraft, means a grouping of aircraft based upon intended use or operating limitations Examples include: transport, normal, utility, acrobatic, limited, restricted, and provisional

Aircraft flight manual (AFM)   Also called the Pilot’s Operating Handbook (POH), a document developed by the aircraft manufacturer and approved by the FAA It is specific to a particular make and model aircraft by a serial number, and contains operating procedures and limitations

Aircraft operating instructions (AOI)   An alternative to the approved term, Pilot's Operating Handbook

Airfoil   Any surface, such as a wing or propeller, which provides aerodynamic force when it interacts with a moving stream of air

Airmanship   A sound acquaintance with the principles of flight, the ability to operate an airplane with competence and precision both on the ground and in the air, and the exercise of sound judgment that results in optimal operational safety and efficiency

Airmanship skills   The skills of coordination, timing, control touch, and speed sense in addition to the motor skills required to fly an aircraft

Airport   An area of land or water that is used or intended to be used for the landing and takeoff of aircraft, including its buildings and facilities, if any

Airport/facility directory (A/FD)   A publication of the Federal Aviation Administration containing information on all airports, seaplane bases, and heliports open to the public The A/FD contains communication data, navigational facilities, and certain special notices and procedures

Airspace   The space above a certain geographical area

Airworthiness   A state in which an aircraft or component meets the conditions of its type design and is in a condition for safe operation

Airworthiness Certificate   A certificate issued by the FAA to aircraft that have been proven to meet the minimum standards set down by the Code of Federal Regulations

Airworthiness Directive (AD)   A regulatory notice sent out by the FAA to the registered owner of an aircraft informing the owner of a condition that prevents the aircraft from continuing to meet its conditions for airworthiness Compliance with AD notes must be within the required time limit, and the fact of compliance, the date of compliance, and the method of compliance must be recorded in the aircraft’s maintenance records

Altimeter   A flight instrument that indicates altitude by sensing pressure changes

AME   See Aviation Medical Examiner

Ammeter   An instrument installed in series with an electrical load used to measure the amount of current flowing through the load

Angle of attack (AOA)   The acute angle between the chord line of the airfoil and the direction of the relative wind

Angle of incidence   The angle formed by the chord line of the wing at the keel of a WSC and a line parallel to the longitudinal axis of the WSC carriage The angle of incidence changes in the WSC controlled by the pilot

Anhedral   A downward slant from root to tip of an aircraft’s wing opposite from dihedral

Annual inspection   A complete inspection of an aircraft and engine, required by the Code of Federal Regulations, to be accomplished every 12 calendar months on all certificated aircraft Only an A&P technician holding an Inspection Authorization can conduct an annual inspection

AOA   See angle of attack

AOI   See aircraft operating instructions

Arm   The horizontal distance in inches from the reference datum line to the center of gravity of an item Used in weight and loading calculations

AROW   Certificates and documents required to be onboard an aircraft to determine airworthiness: Airworthiness certificate, Registration certificate, Operating limitations, Weight and balance data

ASOS   See Automated Surface Observing System

Aspect ratio   Span of a wing divided by its average chord

Asymmetrical   airfoil An airfoil section that is not the same on both sides of the chord line

ATC   Air traffic control

ATIS   See Automatic Terminal Information Service

Attitude   The position of an aircraft as determined by the relationship of its axes and a reference, usually the earth’s horizon

Attitude of pilot   A personal motivational predisposition to respond to persons, situations, or events in a given manner that can, nevertheless, be changed or modified through training as sort of a mental shortcut to decision-making

Attitude management of pilot   The ability to recognize hazardous attitudes in oneself and the willingness to modify them as necessary through the application of an appropriate antidote thought

Automated flight service station   An FAA air traffic facility that provides pilot briefings, en route radio communications, and VFR search-and-rescue services

Automated Surface Observing System (ASOS)   Weather reporting system which provides surface observations every minute via digitized voice broadcasts and printed reports

Automated Weather Observing System (AWOS)   Automated weather reporting system consisting of various sensors, a processor, a computer- generated voice subsystem, and a transmitter to broadcast weather data

Automatic Terminal Information Service (ATIS)   The continuous broadcast (by radio or telephone) of recorded noncontrol, essential but routine information in selected terminal areas

Aviation Medical Examiner (AME)   A medical doctor authorized to perform aviation medical exams for aviators

Axes of an aircraft   Three imaginary lines that pass through an aircraft’s center of gravity The axes can be considered as imaginary axes around which the aircraft turns The three axes pass through the center of gravity at 90° angles to each other The axis from nose to tail is the longitudinal axis, the axis that passes side to side along the wingspan is the lateral axis and the axis that passes vertically through the center of gravity is the vertical axis

Ballistic parachute system (BPS)   An optional parachute system activated by the pilot where the parachute is extracted for the WSC by a rocket

Balloon   The result of a roundout (flare) that is too aggressive during landing, causing the aircraft to climb

Bank attitude   The angle of the lateral axis relative to the horizon

Base leg   A flight path at right angles to the landing runway off its approach end The base leg normally extends from the downwind leg to the intersection of the extended runway centerline

Battens   The airfoil ribs of a WSC that are removed to fold up the wing

Best-angle-of-climb speed (VX)   The speed at which the aircraft produces the most gain in altitude in a given distance

Best glide   The airspeed at which the aircraft glides the furthest for the least altitude lost when in non-powered flight

Best-rate-of-climb speed (VY)   The speed at which the aircraft produces the most gain in altitude in a given amount of time

BPS   See ballistic parachute system

Calibrated airspeed (CAS)   Indicated airspeed corrected for installation error and instrument error Although manufacturers attempt to keep airspeed errors to a minimum, it is not possible to eliminate all errors throughout the airspeed operating range This error is generally greatest at low airspeeds In the cruising and higher airspeed ranges, indicated airspeed and calibrated airspeed are approximately the same Refer to the airspeed calibration chart to correct for possible airspeed errors

Camber   The curvature of a wing when looking at a cross section A wing has upper camber on its top surface and lower camber on its bottom surface

Carburetor   (1) Pressure: A hydromechanical device employing a closed feed system from the fuel pump to the discharge nozzle It meters fuel through fixed jets according to the mass airflow through the throttle body and discharges it under a positive pressure Pressure carburetors are distinctly different from float-type carburetors, as they do not incorporate a vented float chamber or suction pickup from a discharge nozzle located in the venturi tube (2) Float-type: Consists essentially of a main air passage through which the engine draws its supply of air, a mechanism to control the quantity of fuel discharged in relation to the flow of air, and a G-4 means of regulating the quantity of fuel/air mixture delivered to the engine cylinders

Carburetor ice   Ice that forms inside the carburetor due to the temperature drop caused by the vaporization of the fuel Induction system icing is an operational hazard because it can cut off the flow of the fuel/air charge or vary the fuel/air ratio

Carriage   The engine and seats, attached by a structure to wheels; sometimes referred to as the fuselage, cockpit, chaise, or airframe

Carriage keel   The lower center tube in the carriage that runs fore and aft which connects the mast to the front tube

CAS   See calibrated airspeed

Cavitation   A condition that exists in a fluid pump when there is not enough pressure in the reservoir to force fluid to the inlet of the pump The pump picks up air instead of fluid

Center of gravity   (CG) The point at which an aircraft would balance if it were possible to suspend it at that point It is the mass center of the aircraft, or the theoretical point at which the entire weight of the WSC is assumed to be concentrated It may be expressed in inches from the reference datum, or in percent of mean aerodynamic chord (MAC) The location depends on the distribution of weight in the aircraft

Center of lift   The location along the chord line of an airfoil at which all the lift forces produced by the airfoil are considered to be concentrated

Center of pressure (CP)   The point along the wing chord line where lift is considered to be concentrated

Centrifugal force   The apparent force occurring in curvilinear motion acting to deflect objects outward from the axis of rotation For instance, when pulling out of a dive, it is the force pushing you down in your seat

Centripetal force   The force in curvilinear motion acting toward the axis of rotation For instance, when pulling out of a dive, it is the force that the seat exerts on the pilot to offset the centrifugal force

Certificated Flight Instructor (CFI)   A flight instructor authorized by the FAA to provide flight instruction in designated category of aircraft

Certified Flight Instructor with a Sport Pilot Rating (CFIS)   A flight instructor authorized by the FAA to provide flight instruction in designated category of aircraft for sport pilots only

CFI   See Certified Flight Instructor

CFIS   See Certified Flight Instructor with a Sport Pilot Rating

CFR   See Code of Federal Regulations

CG   See center of gravity

Checklist   A list of procedures that provides a logical and standardized method to operate a particular make and model aircraft

Checkride   A practical test administered by an FAA examiner or designated examiner for the purpose of issuing an FAA certificate or rating

Chord line   An imaginary straight line drawn through an airfoil from the leading edge to the trailing edge

Circuit breaker   A circuit-protecting device that opens the circuit in case of excess current flow A circuit breaker differs from a fuse in that it can be reset without having to be replaced

CL   See coefficient of lift

Class A Airspace   Airspace from 18,000 feet MSL up to and including FL 600, including the airspace overlying the waters within 12 NM of the coast of the 48 contiguous states and Alaska; and designated international airspace beyond 12 NM of the coast of the 48 contiguous states and Alaska within areas of domestic radio navigational signal or ATC radar coverage, and within which domestic procedures are applied

Class B Airspace   Airspace from the surface to 10,000 feet MSL surrounding the nation’s busiest airports in terms of IFR operations or passenger numbers The configuration of each Class B airspace is individually tailored and consists of a surface area and two or more layers, and is designed to contain all published instrument procedures once an aircraft enters the airspace For all aircraft, an ATC clearance is required to operate in the area, and aircraft so cleared receive separation services within the airspace

Class C Airspace   Airspace from the surface to 4,000 feet above the airport elevation (charted in MSL) surrounding those airports having an operational control tower, serviced by radar approach control, and having a certain number of IFR operations or passenger numbers Although the configuration of each Class C airspace area is individually tailored, the airspace usually consists of a 5 NM radius core surface area that extends from the surface up to 4,000 feet above the airport elevation, and a 10 NM radius shelf area that extends from 1,200 feet to 4,000 feet above the airport elevation

Class D Airspace   Airspace from the surface to 2,500 feet above the airport elevation (charted in MSL) surrounding those airports that have an operational control tower The configuration of each Class D airspace area is individually tailored, and when instrument procedures are published, the airspace will normally be designed to contain the procedures

Class E Airspace   Airspace that is not Class A, Class B, Class C, or Class D, and is controlled airspace

Class G Airspace   Airspace that is uncontrolled, except when associated with a temporary control tower, and has not been designated as Class A, Class B, Class C, Class D, or Class E airspace

Clear air turbulence   Turbulence not associated with any visible moisture

Clearance   ATC permission for an aircraft to proceed under specified traffic conditions within controlled airspace, for the purpose of providing separation between known aircraft

Code of Federal Regulations (CFR)   Regulations issued by the U S Federal Government as published in the Federal Register

Coefficient of lift (CL)   The ratio between lift pressure and dynamic pressure

Cold front   The boundary between two air masses where cold air is replacing warm air

Combustion   Process of burning the fuel/air mixture in the engine in a controlled and predictable manner

Combustion chamber   The section of the engine into which fuel is injected and burned

Common Traffic Advisory Frequency (CTAF)   A frequency designed for the purpose of carrying out airport advisory practices while operating to or from an airport without an operating control tower The CTAF may be a UNICOM, Multicom, automated flight service station, or tower frequency and is identified in appropriate aeronautical publications

Controlled airspace   An airspace of defined dimensions within which air traffic control service is provided to IFR flights and to VFR flights in accordance with the airspace classification Note: “controlled airspace” is a generic term that encompasses Class A, Class B, Class C, Class D, and Class E airspace

Control bar   The structural part of the wing that connects the flying wires the the wing and keel This is also used for the pilot to control the WSC pitch and roll in flight

Control frame   The wing structural triangle which connects the control bar to the wing keel and provides the structure for the lower flying wire attachments

Control pressure   The amount of physical exertion on the control column necessary to achieve the desired attitude

Control tower   A terminal facility that uses air/ground communications, visual signaling, and other devices to provide ATC services to aircraft operating in the vicinity of an airport or on the movement area Authorizes aircraft to land or takeoff at the airport controlled by the tower or to transit the Class D airspace area regardless of the flight plan or weather conditions May also provide approach control services (radar or nonradar)

Controllability   A measure of the response of an aircraft relative to the pilot’s flight control inputs

Course   The intended direction of flight in the horizontal plane measured in degrees from north

Coordinated turn   Turn made by an aircraft where the horizontal component of lift is equal to the centrifugal force of the turn

Crab angle   The angle formed between the direction an aircraft is pointed and the direction it is tracking over the ground, resulting from a crosswind component Also called the wind correction angle

Crewmember   A person assigned to perform duty in an aircraft during flight time

Crew resource management (CRM)   The application of team management concepts in the flight deck environment, including single pilots of general aviation aircraft Pilots of small aircraft, as well as crews of larger aircraft, must make effective use of all available resources: human resources, hardware, and information Human resource groups include but are not limited to pilots, dispatchers, cabin crewmembers, maintenance personnel, and air traffic controllers

Critical angle of attack   The angle of attack at which a wing stalls regardless of airspeed, flight attitude, or weight

CRM   See crew resource management

Crossbar   The structural component of the WSC wing that holds the leading edges in place

Crosswind   Wind blowing across rather than parallel to the direction of flight In a traffic pattern, the crosswind leg is a flight path at right angles to the landing runway off its upwind end

Crosswind component   The wind component, measured in knots, at 90° to the longitudinal axis of the runway

Crosswind correction   Correction applied in order to maintain a straight ground track during flight when a crosswind is present

Crosswind landing   Landing made with a wind that is blowing across rather than parallel to the landing direction

Crosswind takeoffs   Takeoffs made during crosswind conditions

CTAF   See Common Traffic Advisory Frequency

Datum   An imaginary vertical plane or line from which all measurements of moment arm are taken The datum is established by the manufacturer

DECIDE Model   Model developed to help pilots remember the six-step decision-making process: Detect, Estimate, Choose, Identify, Do, Evaluate

Density altitude   Pressure altitude corrected for variations from standard temperature When conditions are standard, pressure altitude and density altitude are the same If the temperature is above standard, the density altitude is higher than pressure altitude If the temperature is below standard, the density altitude is lower than pressure altitude This is an important altitude because it is directly related to the PPC’s performance

Departure leg   The leg of the rectangular traffic pattern that is a straight course aligned with, and leading from, the takeoff runway

Designated pilot examiner (DPE)   An individual designated by the FAA to administer practical tests to pilot applicants

Detonation   The sudden release of heat energy from fuel in an aircraft engine caused by the fuel-air mixture reaching its critical pressure and temperature Detonation occurs as a violent explosion rather than a smooth burning process

Dew   Moisture that has condensed from water vapor Usually found on cooler objects near the ground, such as grass, as the near-surface layer of air cools faster than the layers of air above it

Dewpoint   The temperature at which air reaches a state of water saturation

Dihedral   The positive acute angle between the lateral axis of an airplane and a line through the center of a wing or horizontal stabilizer Dihedral contributes to the lateral stability of an aircraft

Directional stability   Stability about the vertical axis of an aircraft, whereby an aircraft tends to return, on its own, to flight aligned with the relative wind when disturbed from that equilibrium state The wing design is the primary contributor to directional stability, causing a WSC in flight to align with the relative wind

Ditching   Emergency landing in water

Double-surface wing   Two pieces of fabric for most of the WSC wing which enclose the crossbar; typically used for higher speed wings

Downwind leg   Leg of the traffic pattern flown parallel to the landing runway, but in a direction opposite to the intended landing direction

DPE   See designated pilot examiner

Drag   An aerodynamic force on a body acting parallel and opposite to the relative wind The resistance of the atmosphere to the relative motion of an aircraft Drag opposes thrust and limits the speed of the aircraft

Drag coefficient (CD)   A dimensionless number used to define the amount of total drag produced by an aircraft

Drift angle   Angle between heading and track

Drift correction   Correction that is applied to counter the affects of wind on an aircraft’s flight and ground track

Dual flight   Flight time that is received and logged as training time Dual flight time must be endorsed by a Certificated Flight Instructor

Dynamic hydroplaning   A condition that exists when landing on a surface with standing water deeper than the tread depth of the tires When the brakes are applied, there is a possibility that the brake will lock up and the tire will ride on the surface of the water, much like a water ski When tires are hydroplaning, directional control and braking action are virtually impossible An effective anti-skid system can minimize the effects of hydroplaning

Dynamic pressure   The pressure a moving fluid would have if it were stopped Reference 14 CFR section 61 51(h)

Dynamic stability   The property of an aircraft that causes it, when disturbed from straight-and level flight, to develop forces or moments that restore the original condition of straight and level

EFAS   See En Route Flight Advisory Service

EGT   See exhaust gas temperature

E-LSA (Experimental Light-Sport Aircraft)   An aircraft issued an experimental certificate under 14 CFR part 21

ELT   See emergency locator transmitter

Emergency frequency   Frequency that is used by aircraft in distress to gain ATC assistance 121 5 MHz is an international emergency frequency guarded by Flight Service Stations and some military and civil aircraft Reference AIM paragraph 6-3-1

Emergency locator transmitter (ELT)   A small, selfcontained radio transmitter that will automatically, upon the impact of a crash, transmit an emergency signal on 121 5, 243 0, or 406 0 MHz

Energy management   The ability for a pilot to maintain high kinetic energy levels in turbulent air and while near the ground is energy management for WSC Higher speed and higher power is higher energy Lower speed and lower power is lower energy

En Route Flight Advisory Service (EFAS)   An en route weather-only AFSS service

Encoding altimeter   A special type of pressure altimeter used to send a signal to the air traffic controller on the ground, showing the pressure altitude the aircraft is flying

Error chain   A series of mistakes that may lead to an accident or incident Two basic principles generally associated with the creation of an error chain are: (1) one bad decision often leads to another; and (2) as a string of bad decisions grows, it reduces the number of subsequent alternatives for continued safe flight Aeronautical decision making is intended to break the error chain before it can cause an accident or incident

Evaporation   The transformation of a liquid to a gaseous state, such as the change of water to water vapor

Exhaust   The rear opening of a turbine engine exhaust duct The nozzle acts as an orifice, the size of which determines the density and velocity of the gases as they emerge from the engine

Exhaust gas temperature (EGT)   The temperature of the exhaust gases as they leave the cylinders of a reciprocating engine

Exhaust manifold   The part of the engine that collects exhaust gases leaving the cylinders

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