Glossary of Terms
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Aircraft-based augmentation system
An augmentation system which augments and/or integrates the information obtained from the other GNSS elements with information available on board the aircraft.
‘Abortive Start’ (turbine engines) means an attempt to start, in which the engine lights up, but fails to accelerate.
‘Accessory drives’ means any drive shaft or utility mounting pad, furnished as a part of the auxiliary power unit, that is used for the extraction of power to drive accessories, components, or controls essential to the operation of the auxiliary power unit or any of its associated systems.
Accident. An occurrence associated with the operation of an aircraft which, in the case of a manned aircraft, takes place
Accredited representative. A person designated by a State, on the basis of his or her qualifications, for the purpose of
A.C.D. - Additional Control Device
Aircraft classification number (ACN). A number expressing the relative effect of an aircraft on a pavement for a specified
“acrobatic flight” means manoeuvres intentionally performed by an aircraft involving an
Acts of unlawful interference
Acts of unlawful interference. These are acts or attempted acts such as to jeopardize the safety of civil aviation, including but
Air defence identification zone. Special designated airspace of defined dimensions within which aircraft are required to
Admission. The permission granted to a person to enter a State by the public authorities of that State in accordance with its
“ADS Agreement” means an ADS reporting plan which establishes the conditions of ADS
“advisory airspace” means advisory areas or advisory routes
“advisory area” means an area designated by the appropriate ATS authority within a flight
Aerodrome. A defined area on land or water (including any buildings, installations and equipment) intended to be used either
Aerodrome climatological summary
Aerodrome climatological summary. Concise summary of specified meteorological elements at an aerodrome, based on
Aerodrome control tower
Aerodrome control tower. A unit established to provide air traffic control service to aerodrome traffic
Aerodrome elevation. The elevation of the highest point of the landing area.
Aerodrome identification sign
Aerodrome identification sign. A sign placed on an aerodrome to aid in identifying the aerodrome from the air.
Aerodrome operating minima
“aerodrome operating minima” means the limits of usability of an aerodrome for:
Aerodrome reference point
Aerodrome reference point. The designated geographical location of an aerodrome.
Aerodrome traffic density
Aerodrome traffic density.
Aeronautical beacon. An aeronautical ground light visible at all azimuths, either continuously or intermittently, to designate a
Aeronautical chart. A representation of a portion of the Earth, its culture and relief, specifically designated to meet the
Aeronautical ground light
Aeronautical ground light. Any light specially provided as an aid to air navigation, other than a light displayed on an aircraft.
Aeronautical operational control
Aeronautical operational control (AOC). Communication required for the exercise of authority over the initiation, continuation,
Aeroplane reference field length
Aeroplane reference field length. The minimum field length required for take-off at maximum certificated take-off mass, sea
Aircraft earth station (AES). A mobile earth station in the aeronautical mobile-satellite service located on board an aircraft
Ground earth station (GES). An earth station in the fixed satellite service, or, in some cases, in the aeronautical
Note.— This definition is used in the ITU’s Radio Regulations under the term “aeronautical earth station”. The
Afterburning. A mode of engine operation wherein a combustion system fed (in whole or part) by vitiated air is used.
Aeronautical fixed telecommunication network (AFTN). A worldwide system of aeronautical fixed circuits provided, as
Aeronautical Information Publication (AIP). A publication issued by or with the authority of a State and containing
AIP Supplement. Temporary changes to the information contained in the AIP which are published by means of special pages
Air operator’s certificate
“air operator’s certificate” (AOC) means a certificate authorising an operator to
“air traffic” means all aircraft in flight or operating on the manoeuvring area of an
Air traffic advisory service
“air traffic advisory service” means a service provided by the appropriate ATS authority
Air traffic control clearance
“air traffic control clearance” means authorisation for an aircraft to proceed under
Air traffic control service
“air traffic control service” means a service provided for the purpose of:
(a) preventing collisions between aircraft, and on the manoeuvring area, between
Air traffic service
“air traffic service” (ATS) includes the following services, namely, flight information
Air traffic services airspaces
“air traffic services airspaces” means airspaces of dimensions defined and alphabetically
Air traffic services reporting office
“air traffic services reporting office” means a unit provided by the appropriate authority
Air transit route
Air transit route. A defined route for the air transiting of helicopters.
Air transport undertaking
“air transport undertaking” means an undertaking the business of which includes the
“air-ground communication” means a two-way communication between aircraft and
Air-ground control radio station
“air-ground control radio station” means an aeronautical telecommunication station having
Air-report. A report from an aircraft in flight prepared in conformity with requirements for position, and operational and/or
“air-taxiing” means the movement of a helicopter above the surface of an aerodrome,
AIRAC. An acronym (aeronautical information regulation and control) signifying a system aimed at advance notification based
Airborne collision avoidance system
“airborne collision avoidance system (ACAS)” means an aircraft system based on
Aircraft address. A unique combination of twenty-four bits available for assignment to an aircraft for the purpose of airground
Aircraft equipment. Articles, including first-aid and survival equipment and commissary supplies, but not spare parts or
Aircraft observation. The evaluation of one or more meteorological elements made from an aircraft in flight.
Aircraft operating manual
“aircraft operating manual” means a manual, acceptable to the state of the operator,
Aircraft proximity. A situation in which, in the opinion of a
Aircraft security check
Aircraft security check. An inspection of the interior of an aircraft to which passengers may have had access and an inspection
Aircraft stand. A designated area on an apron intended to be used for parking an aircraft.
Aircraft station (RR S1.83). A mobile station in the aeronautical
‘Aircraft Variant’ as used with respect to the licensing and operation of flight crew, means an aircraft of the same basic certificated type which contain modifications not resulting in significant changes of handling and/or flight characteristic, or flight crew complement, but causing significant changes to equipment and/or procedures.
‘Airframe’ means the fuselage, booms, nacelles, cowlings, fairings, aerofoil surfaces (including rotors but excluding propellers and rotating aerofoils of engines), and landing gear of an aircraft and their accessories and controls.
The consistent use of good judgement and well-developed knowledge, skills and attitudes to accomplish flight
AIRMET information. Information issued by a meteorological watch office concerning the occurrence or expected
AIRPROX. The code word used in an air traffic incident
A power-driven lighter-than-air aircraft.
Airside. The movement area of an airport, adjacent terrain and buildings or portions thereof, access to which is controlled.
Airway. A control area or portion thereof established in the form of a corridor.
AIS product. Aeronautical information provided in the form of the elements of the Integrated Aeronautical Information
ALERFA. The code word used to designate an alert phase.
Alerting post. Any facility intended to serve as an
“alerting service” means a service provided by the appropriate ATS authority to notify
ALSF-1: Approach Lighting System with Sequenced Flashing Lights configuration 1
ALSF-2: Approach Lighting System with Sequenced Flashing Lights configuration 2
Alternate aerodrome or heliport
“alternate aerodrome or heliport” means an aerodrome or heliport (including the
‘Alternate airport’ means an airport at which an aircraft may land if a landing at the intended airport becomes inadvisable.
Altimetry system error
“altimetry system error (ASE)” means the difference between the altitude indicated
Area minimum altitude (AMA). The minimum altitude to be used under instrument meteorological conditions (IMC), that
Ampere (A). The ampere is that constant electric current which, if maintained in two straight parallel conductors of infinite
Angle of Incidence
The Angle of Incidence is the angle at which a wing is mounted onto a fuselage relative to the longitudinal axis. It is also known as the Rigger's Angle.
ANSP - Air Navigation Service Provider
“anti-collision light” means:
Anticipated operating conditions
Anticipated operating conditions. Those conditions which are known from experience or which can be reasonably envisaged
Abbreviated Precision Approach Path Indicator. A precision approach path indicator (PAPI) consisting of only two sharp cutoff light units situated on the left side of the runway.
Advance Passenger Information (API) System. An electronic communications system whereby required data elements are
Approach and landing operations using instrument approach procedures
“Approach and landing operations using instrument approach procedures” means
Approach and landing operations using instrument approach procedures. Instrument approach and landing operations are
An instrument approach and landing which utilizes lateral guidance but
Category IIIA (CAT IIIA) operation. A precision instrument approach and landing with:
Approach control service
“approach control service” means air traffic control service for arriving or departing
Approach phase (Engines)
Approach phase. The operating phase defined by the time during which the engine is operated in the approach operating mode.
Take-off phase. The operating phase defined by the time during which the engine is operated at the rated thrust.
Appropriate ATS authority
“appropriate ATS authority” means in relation to the State, the Authority and, in relation to
“appropriate person” means an authorised officer of the Authority as defined in the
Approval Dangerous Goods
Approval. An authorization granted by an appropriate national authority for:
Training conducted under special curricula and supervision approved by a Contracting State.
Approved training organization
An organization approved by and operating under the supervision of a Contracting State in accordance with the requirements of Annex 1 to perform approved training.
“apron” means a defined area at a land aerodrome intended to accommodate aircraft for the
APV – Approach Procedure with Vertical guidance. This term is used for RNP APCH operations that include vertical. guidance. That is, those flown to LNAV/VNAV or LPV minima.
Area control centre
“area control centre” (ACC) means a unit established by the appropriate ATS authority to provide
Area control service
“area control service” means air traffic control service for controlled flights in control
“area navigation” means a method of navigation which permits aircraft operation on any
Area navigation route
“area navigation route” means an ATS route established by the appropriate ATS authority
Arrival routes. Routes identified in an instrument approach procedure by which aircraft may proceed from the en-route phase
Accelerate-stop distance available (ASDA). The length of the take-off run available plus the length of stopway, if provided.
ASHTAM. A special series NOTAM notifying by means of a specific format change in activity of a volcano, a volcanic
Associated aircraft systems
Associated aircraft systems. Those aircraft systems drawing electrical/pneumatic power from an auxiliary power unit during
. A common industry referencing standard for aircraft technical documentation.
“ATC” means the symbol used to designate air traffic control;
Air traffic flow management (ATFM). A service established with the objective of contributing to a safe, orderly and
Automatic terminal information service (ATIS). The automatic provision of current, routine information to arriving and
Atmosphere, International Standard
‘Atmosphere, International Standard’ means the atmosphere defined in ICAO Document 7488/2.
NOTE: ρ is the density appropriate to the altitude and p/ρσ the relative density is indicated by σ.
“ATS” means the symbol used to designate air traffic services;
“ATS route” means a route specified by the appropriate ATS authority designed for
ATS surveillance service
A term used to indicate a service provided directly by means of an ATS surveillance system.
ATS surveillance system
A generic term meaning variously, ADS-B, PSR, SSR or any comparable ground-based system that
Note.— A comparable ground-based system is one that has been demonstrated, by comparative assessment or other methodology, to have a level of safety and performance equal to or better than monopulse SSR.
“authorised officer” means an authorised officer of the Authority as defined in
Authorized agent. A person who represents an aircraft operator and who is authorized by or on behalf of such operator to act
Automatic Dependent Surveillance
“Automatic Dependent Surveillance” (ADS) means a surveillance technique in which
Automatic dependent surveillance-broadcast (ADS-B) OUT. A function on an aircraft or vehicle that periodically broadcasts
Auxiliary Power Unit (APU)
‘Auxiliary Power Unit (APU)’ means any gas turbine-powered unit delivering rotating shaft
‘Auxiliary rotor’ means a rotor that principally serves to counteract the effect of the main rotor torque on a rotorcraft and/or to manoeuvre the rotorcraft about one or more of its three principle axes
Background check. A check of a person’s identity and previous experience, including where legally permissible, any criminal
A non-power-driven lighter-than-air aircraft.
Bare Earth. Surface of the Earth including bodies of water and permanent ice and snow, and excluding vegetation and
Barrette. Three or more aeronautical ground lights closely spaced in a transverse line so that from a distance they appear as a
“base turn” means a turn executed by the aircraft during the initial approach between the
Becquerel (Bq). The activity of a radionuclide having one spontaneous nuclear transition per second.
Bit error rate (BER). The number of bit errors in a sample divided by the total number of bits in the sample, generally
‘Beta Control’ means a system whereby the propeller can be operated at blade angles directly selected by the air crew, or by other means, and normally used during the approach and ground handling.
Blind transmission. A transmission from one station to
‘Boost Pressure’ (piston engines) means the manifold pressure measured relative to standard sea level atmospheric pressure.
Border integrity. The enforcement, by a State, of its laws and/or regulations concerning the movement of goods and/or
‘Brake Horsepower’ means the power delivered at the propeller shaft (main drive or main output) of an aircraft engine.
‘BTPD’ means body temperature, pressure, dry, i.e. 37°C, ambient pressure and no water vapour.
‘BTPS’ means body temperature, pressure, saturated, i.e.37°C, ambient pressure and saturated with
Bypass ratio. The ratio of the air mass flow through the bypass ducts of a gas turbine engine to the air mass flow through the
Cabin crew member
“cabin crew member” (CCM) means a crew member who performs, in the interest of the
C.A.D.M. - Central Data Acquisition Module
‘Calibrated airspeed’ (CAS) means indicated airspeed of an aircraft, corrected for position and instrument error. Calibrated airspeed is equal to true airspeed in standard atmosphere at sea level.
CALVERT I / ICAO-1 HIALS
CALVERT I / ICAO-1 HIALS: ICAO-compliant configuration 1 High Intensity Approach Lighting System
CALVERT II / ICAO-2 HIALS
CALVERT II / ICAO-2 HIALS: ICAO-compliant configuration 2 High Intensity Approach Lighting System
Candela (cd). The luminous intensity, in the perpendicular direction, of a surface of 1/600 000 square metre of black body at
Canopy. Bare Earth supplemented by vegetation height.
Capacitor discharge light
Capacitor discharge light. A lamp in which high-intensity flashes of extremely short duration are produced by the discharge of
“cargo” includes mail and animals.
Cargo aircraft. Any aircraft, other than a passenger aircraft, which is carrying goods or property.
Carrier-to-multipath ratio (C/M). The ratio of the carrier power received directly, i.e. without reflection, to the multipath
Carrier-to-noise density ratio (C/No). The ratio of the total carrier power to the average noise power in a 1 Hz bandwidth,
Causes. Actions, omissions, events, conditions, or a combination thereof, which led to the accident or incident. The identification
Continuous descent final approach (CDFA) means a technique, consistent with stabilised approach procedures, for flying the final-approach segment of a non-precision instrument approach procedure as a continuous descent, without level-off, from an altitude/height at or above the final approach fix altitude/height to a point approximately 15 m (50 ft) above the landing runway threshold or the point where the flare manoeuvre shall begin for the type of aircraft flown.
“ceiling” means the height above the ground or water as the case may be of the base of the
“change-over point” means the point at which an aircraft navigating on an ATS route
Channel rate. The rate at which bits are transmitted over the RF channel. These bits include those bits used for framing and
Channel rate accuracy
Channel rate accuracy. This is relative accuracy of the clock to which the transmitted channel bits are synchronized. For
Civil aviation inspector
Civil aviation inspector. A civil aviation inspector is an individual, designated by a Contracting State, who is charged with
As used with respect to aeroplanes means a group of single-pilot aeroplane types having similar handling and flight characteristics.
“clearance limit” means the point to which an aircraft is granted an air traffic control
Clearance of goods
Clearance of goods. The accomplishment of the customs formalities necessary to allow goods to enter home use, to be
‘Clearway’ means, for turbine engine powered aeroplanes certificated after August 29, 1959, an area beyond the runway, not less than 152 rn (500 ft) wide, centrally located ab.out the extended centreline of the runway, and under the control of the airport authorities. The clearway is expressed in terms of a clearway plane, extending from the end of the runway with an upward slope not exceeding 1.25%, above which no object or terrain protrudes. However, threshold lights may protrude above the plane if their height above the end of the runway is 0.66 m (26 ins) or less and if they are located to each side of the runway.
Cloud of operational significance
Cloud of operational significance. A cloud with the height of cloud base below 1 500 m (5 000 ft) or below the highest
'Co-pilot' means a pilot serving in any piloting capacity other than as pilot-in-command or
Collision avoidance logic
Collision avoidance logic. The sub-system or part of ACAS that analyses data relating to an intruder and own aircraft, decides
Commencement of journey
Commencement of journey. The point at which the person began his journey, without taking into account any airport at
Commercial air transport operation
An aircraft operation involving the transport of passengers, cargo or mail for
Commercial transport aircraft
“commercial transport aircraft” means an aircraft used or intended to be used by the
Commissary supplies. Items, either disposable or intended for multiple use, that are used by the aircraft operator for
Common Mark Registering
Common mark registering authority. The authority maintaining the non-national register or, where appropriate, the part
A combination of skills, knowledge and attitudes required to perform a task to the prescribed standard.
An action that constitutes a task that has a triggering event and a terminating event that clearly defines its
‘Compressor air’ means compressed air that is provided by the APU to do work whether it is extracted or bled from any point of the compressor section of the gas turbine engine or produced from a compressor driven by the APU.
Configuration (as applied to the aeroplane). A particular combination of the positions of the moveable elements, such as
Configuration deviation list
“configuration deviation list” (CDL) means a list established by the organisation
“congested area” means a densely populated area which is substantially used for
Consignment of dangerous goods
Consignment. One or more packages of dangerous goods accepted by an operator from one shipper at one time and at one
Consultation. Discussion with a meteorologist or another qualified person of existing and/or expected meteorological
A runway is considered to be contaminated when more than 25 % of the runway surface
Continuing airworthiness. The set of processes by which an aircraft, engine, propeller or part complies with the applicable
Contour line. A line on a map or chart connecting points of equal elevation.
“control zone” (CTR) means a controlled airspace extending upwards from the surface of the
Controlled aerodrome. An aerodrome at which air traffic control service is provided to aerodrome traffic.
“controlled flight” means any flight which is provided with air traffic control
Controlled VFR flight
“controlled VFR flight” means a controlled flight conducted in accordance with the
Corporate aviation. The non-commercial operation or use of aircraft by a company for the carriage of passengers or goods as
C.O.T.S. - Commercial Off-The-Shelf
“controller-pilot data link communications” (CPDLC) means a means of communication
Cyclic redundancy check (CRC). A mathematical algorithm applied to the digital expression of data that provides a level of
Recognition of alternative means or prior qualifications.
‘Critical Altitude’ (piston engines) means the maximum attitude at which, in standard atmosphere, it is possible to maintain, at a specified rotational speed without ram, a specified power or a specified manifold pressure. Unless otherwise stated, the critical altitude is the maximum altitude at which it is possible to maintain, without ram, at the maximum continuous rotational speed, one of the following:-
‘Critical Engine’ means the engine whose failure would most adversely affect the performance or handling qualities of an aircraft.
Critical Phases of Flight
Critical phases of flight in the case of aeroplanes means the take-off run, the take-off flight path, the final approach, the missed approach, the landing, including the landing roll, and any other phases of flight as determined by the pilot-in-command or commander;
A flight between a point of departure and a point of arrival following a pre-planned route using standard
“cruise climb” means an aeroplane cruising technique resulting in a net increase in altitude
Cruise relief pilot
“cruise relief pilot” means a flight crew member who is assigned to perform pilot
“cruising level” means a level maintained during a significant portion of a flight;
Culture. All man-made features constructed on the surface of the Earth, such as cities, railways and canals.
Recommendation.— An area of thunderstorms and cumulonimbus clouds should be considered:
current flight plan
“current flight plan” means the flight plan together with any changes caused by subsequent
Data link flight information services (D-FIS). The provision of FIS via data link.
A runway is considered damp when the surface is not dry, but when the moisture on it does not
“danger area” means an airspace of dimensions specified by the appropriate ATS authority
“dangerous goods” means articles or substances which are capable of posing a risk
Dangerous goods accident.
Dangerous goods accident. An occurrence associated with and related to the transport of dangerous goods by air which results
Datum. Any quantity or set of quantities that may serve as a reference or basis for the calculation of other quantities
DCPC - Direct Controller/Pilot Communications
Dispatch Deviation Procedures Guide (DDPG). Manual to identify any procedure to dispatch an aircraft
De-icing/anti-icing facility. A facility where frost, ice or snow is removed (de-icing) from the aeroplane to provide clean
Decision altitude (DA) or decision height (DH). A specified altitude or height in the precision approach or approach with
Decision altitude (DA) or decision height (DH)
“decision altitude (DA) or decision height (DH)” means a specified altitude or
‘Decision Height’, with respect to the operation of aircraft, means the wheel height above the runway elevation by which a go-around must be initiated unless adequate visual reference has been established and the aircraft position and approach path have been visually assessed as satisfactory to continue the approach and landing in safety.
Declarant. Any person who makes a goods declaration or in whose name such a declaration is made.
Defined point after take-off or before landing
“defined point after take-off or before landing” means, in the case of a multi-engine
Digital Elevation Model (DEM). The representation of terrain surface by continuous elevation values at all intersections of a
Density altitude is the altitude relative to the standard atmosphere conditions (International Standard Atmosphere) at which the air density would be equal to the indicated air density at the place of observation, or, in other words, the height when measured in terms of the density of the air rather than the distance from the ground. "Density Altitude" is the pressure altitude adjusted for non-standard temperature.
Both an increase in temperature, pressure, and, to a much lesser degree, humidity will cause an increase in density altitude. Thus, in hot and humid conditions, the density altitude at a particular location may be significantly higher than the true altitude.
In aviation the density altitude is used to assess the aircraft's aerodynamic performance under certain weather conditions. The lift generated by the aircraft's airfoils and the relation between indicated and true airspeed are also subject to air density changes. Furthermore, the power delivered by the aircraft's engine is affected by the air density and air composition.
Dependent parallel approaches
Dependent parallel approaches. Simultaneous approaches to parallel or near-parallel instrument runways where radar
Deportation order. A written order, issued by the competent authorities of a State and served upon a deportee, directing him
Deportee. A person who had legally been admitted to a State by its authorities or who had entered a State illegally, and who
Derived version of a helicopter. A helicopter which, from the point of view of airworthiness, is similar to the noise certificated
Design landing mass
Design landing mass. The maximum mass of the aircraft at which, for structural design purposes, it is assumed that it will be
Design take-off mass
Design take-off mass. The maximum mass at which the aircraft, for structural design purposes, is assumed to be planned to
Design taxiing mass
Design taxiing mass. The maximum mass of the aircraft at which structural provision is made for load liable to occur during
DETRESFA. The code word used to designate a distress phase.
Direct transit area
Direct transit area. A special area established in an international airport, approved by the public authorities concerned and
Direct transit arrangements
Direct transit arrangements. Special arrangements approved by the public authorities concerned by which traffic which is
Discrete source damage
Discrete source damage. Structural damage of the aeroplane that is likely to result from: impact with a bird, uncontained fan
Disembarkation. The leaving of an aircraft after a landing, except by crew or passengers continuing on the next stage of the
Disinfection. The procedure whereby health measures are taken to control or kill infectious agents on a human or animal
Disinsection. The procedure whereby health measures are taken to control or kill insects present in aircraft, baggage, cargo,
Flight operations officer/flight dispatcher. A person designated by the operator to engage in the control and supervision of
Displaced threshold. A threshold not located at the extremity of a runway.
Disruptive passenger. A passenger who fails to respect the rules of conduct at an airport or on board an aircraft or to follow the
Ditching. The forced landing of an aircraft on water.
Doppler shift. The frequency shift observed at a receiver due to any relative motion between transmitter and receiver.
Double channel simplex
Double channel simplex. Simplex using two frequency
Downstream clearance. A clearance issued to an aircraft by an air traffic control unit that is not the current controlling
DPATO - defined point after take-off (DPATO) means the point, within the take-off and initial climb phase, before which the helicopter’s ability to continue the flight safely, with the critical engine inoperative, is not assured and a forced landing may be required
Defined point before landing (DPBL)’ means the point within the approach and landing phase, after which the helicopter’s ability to continue the flight safely, with the critical engine inoperative, is not assured and a forced landing may be required
A dry runway is one which is neither wet nor contaminated, and includes those paved runways
Dual instruction time
Flight time during which a person is receiving flight instruction from a properly authorized pilot on
Duplex. A method in which telecommunication between two
Simplex. A method in which telecommunication between two
Dynamic load-bearing surface
Dynamic load-bearing surface. A surface capable of supporting the loads generated by a helicopter conducting an emergency
“expected approach time” means the time at which an air traffic control unit expects that
“estimated off blocks time” means the estimated time at which an aircraft will commence
EDTO critical fuel. The fuel quantity necessary to fly to an en-route alternate aerodrome considering, at the most critical point on the route, the most limiting system failure.
EDTO - Extended Diversion Time operations (ETOPS)
EDTO significant system
EDTO significant system. An aeroplane system whose failure or degradation could adversely affect the safety particular to an
E.F.B. - Electronic Flight Bag
Effective acceptance bandwidth
Effective acceptance bandwidth. The range of frequencies with respect to the assigned frequency for which reception is
Effective adjacent channel rejection
Effective adjacent channel rejection. The rejection that is obtained at the appropriate adjacent channel frequency when all
Effective intensity. The effective intensity of a flashing light is equal to the intensity of a fixed light of the same colour which
Electronic aeronautical chart display
Electronic aeronautical chart display. An electronic device by which flight crews are enabled to execute, in a convenient and
Ellipsoid height (Geodetic height). The height related to the reference ellipsoid, measured along the ellipsoidal outer normal
Emergency locator transmitter (ELT). A generic term describing equipment which broadcast distinctive signals on designated
Embarkation. The boarding of an aircraft for the purpose of commencing a flight, except by such crew or passengers as have
Emergency phase. A generic term meaning, as the case may be, uncertainty phase, alert phase or distress phase.
eMRTD. An MRTD (passport, visa or card) that has a contactless integrated circuit embedded in it and the capability of
End-to-end. Pertaining or relating to an entire communication path, typically from (1) the interface between the information
‘Equivalent airspeed’ (EAS) means the calibrated airspeed of an aircraft corrected for adiabatic
Equivalent isotropically radiated power (e.i.r.p.). The product of the power supplied to the antenna and the antenna gain in a
A position that can be established by means of a DME distance, a suitably located NDB or VOR, SRE or PAR fix or any other suitable fix between three and five miles from threshold that independently establishes the position of the aeroplane.
The process of detecting and responding to errors with countermeasures that reduce or eliminate the
Note.— See Attachment C to Chapter 3 of the Procedures for Air Navigation Services — Training (PANS-TRG, Doc 9868)
Essential radio navigation service
Essential radio navigation service. A radio navigation service whose disruption has a significant impact on operations in the
“estimated time of arrival” means for IFR flights, the time at which it is estimated that the
Enhanced vision system (EVS). A system to display electronic real-time images of the external scene achieved through the use
Exhaust Gas Temperature
‘Exhaust Gas Temperature’ (EGT) (turbine engines) means the average temperature of the exhaust gas stream obtained in an approved manner
Exhaust nozzle. In the exhaust emissions sampling of gas turbine engines where the jet effluxes are not mixed (as in some
Extended Diversion Time
Extended diversion time operations (EDTO). Any operation by an aeroplane with two or more turbine engines where the
Extended range operation
Extended range operation. Any flight by an aeroplane with two turbine engines where the flight time at the one engine
External equipment (helicopter). Any instrument, mechanism, part, apparatus, appurtenance, or accessory that is attached to or
‘External load’ means a load that is carried, towed or extends, outside the aircraft fuselage.]
Factor of safety
Factor of safety. A design factor used to provide for the possibility of loads greater than those assumed, and for uncertainties
Final approach fix or point. That fix or point of an instrument approach procedure where the final approach segment
Fan marker beacon
Fan marker beacon. A type of radio beacon, the emissions of which radiate in a vertical fan-shaped pattern
FANS 1/A - Future Air Navigation System 1 or A. (Respectively, Boeing and Airbus Proprietary Air-Ground ATC Data Link Communications Systems)
Farad (F). The capacitance of a capacitor between the plates of which there appears a difference of potential of 1 volt when
Fatigue. A physiological state of reduced mental or physical performance capability resulting from sleep loss or extended
Final approach and take-off area (FATO). A defined area over which the final phase of the approach manoeuvre to hover or
FBL - Used in meteorology meaning "light" as in precipitation or icing.
FDE - Fault Detection and Exclusion
‘Feathered Pitch’ means the pitch setting, specified in the appropriate propeller manual, which in flight with the engine stopped, gives approximately the minimum drag, and corresponds with a windmilling torque of approximately zero.
Forward error correction (FEC). The process of adding redundant information to the transmitted signal in a manner which
Final approach. That part of an instrument approach procedure which commences at the specified final approach fix or point,
b) at the point of interception of the last track specified in the approach procedure; and
Final approach segment
Final approach segment. That segment of an instrument approach procedure in which alignment and descent for landing are
Final take-off speed
‘Final take-off speed’ means the speed of the aeroplane that exists at the end of the take-off path in the en-route configuration with one engine inoperative
“flight information region” means an airspace of defined dimensions designated by the
‘Fire-resistant.’ With respect to materials, components and equipment, means the capability to withstand the application of heat by a flame, as defined for ‘Fireproof‘, for a period of 5 minutes without any failure that would create a hazard to the aircraft.
‘Fireproof.’ With respect to materials, components and equipment, means the capability to withstand the application of heat by a flame, for a period of 15 minutes without any failure that would create a hazard to the aircraft. The flame will have the following characteristics:-
First aid oxygen
‘First aid oxygen’ means the additional oxygen provided for the use of passengers, who do not satisfactorily recover following subjection to excessive cabin altitudes, during which they had been provided with supplemental oxygen.
Fixed light. A light having constant luminous intensity when observed from a fixed point.
Flap extended speed
‘Flap extended speed’ means the highest speed permissible with wing-flaps in a prescribed extended position.
FLAS - Flight Level Allocation Scheme
Flight crew member
A licensed crew member charged with duties essential to the operation of an aircraft during a flight duty
“flight level” means a surface of constant atmospheric pressure which is related to a
Specified information provided to air traffic services units, relative to an intended flight or portion of a flight of an
Flight procedures trainer
See Flight simulation training device.
“flight recorder” means any type of recorder installed in an aircraft for the purpose
Flight safety documents system
“flight safety documents system” means a set of inter-related documentation
“flight status” means an indication of whether or not a given aircraft requires special
Flight time — aeroplanes. The total time from the moment an aeroplane first moves for the purpose of taking off until the
“flight visibility” means the visibility forward from the cockpit of an aircraft in flight;
Foot (ft). The length equal to 0.304 8 metre exactly.
Frangible object. An object of low mass designed to break, distort or yield on impact so as to present the minimum hazard to
Free zone. A part of the territory of a Contracting State where any goods introduced are generally regarded, insofar as import
Frequency channel. A continuous portion of the frequency
Fatigue Risk Management System (FRMS). A data-driven means of continuously monitoring and managing fatigue-related
Gain-to-noise temperature ratio
Gain-to-noise temperature ratio. The ratio, usually expressed in dB/K, of the antenna gain to the noise at the receiver output
GAMET area forecast. An area forecast in abbreviated plain language for low-level flights for a flight information region or
GBAS landing system (GLS) means an approach landing system using ground based augmented global navigation satellite system (GNSS/GBAS) information to provide guidance to the aircraft based on its lateral and vertical GNSS position. It uses geometric altitude reference for its final approach slope.
Geodesic distance. The shortest distance between any two points on a mathematically defined ellipsoidal surface.
Geodetic datum. A minimum set of parameters required to define location and orientation of the local reference system with
Geoid. The equipotential surface in the gravity field of the Earth which coincides with the undisturbed mean sea level (MSL)
Geoid undulation. The distance of the geoid above (positive) or below (negative) the mathematical reference ellipsoid.
Glide path. A descent profile determined for vertical guidance during a final approach.
A non-power-driven heavier-than-air aircraft, deriving its lift in flight chiefly from aerodynamic reactions on surfaces
Glider flight time
The total time occupied in flight, whether being towed or not, from the moment the glider first moves for the
G.P.T. - Ground Programming Tool
Gray (Gy). The energy imparted by ionizing radiation to a mass of matter corresponding to 1 joule per kilogram.
Gregorian calendar. Calendar in general use; first introduced in 1582 to define a year that more closely approximates the
Grid point data
Grid point data in digital form. Computer processed meteorological data for a set of regularly spaced points on a chart, for
“ground handling” means those services necessary for an aircraft’s arrival at and
Ground Idling Conditions
'Ground Idling Conditions’ (turbine engines) means the conditions of minimum rotational speed associated with zero forward speed and the maximum exhaust gas temperature at this speed.
“ground visibility” means the visibility at an aerodrome, as reported by an observer
‘Gyroplane’ means a rotorcraft the rotors of which are not engine driven except for initial starting, but are made to rotate by action of the air when the rotorcraft is moving, and the means of propulsion of which, consisting usually of conventional propellers, is independent of the rotor system.
Hazard beacon. An aeronautical beacon used to designate a danger to air navigation.
A heavier-than-air aircraft supported in flight chiefly by the reactions of the air on one or more power-driven rotors
Helicopter air taxiway
Helicopter air taxiway. A defined path on the surface established for the air taxiing of helicopters.
Helicopter clearway. A defined area on the ground or water, selected and/or prepared as a suitable area over which a helicopter
Helicopter ground taxiway
Helicopter ground taxiway. A ground taxiway intended for the ground movement of wheeled undercarriage helicopters
Helideck. A heliport located on an offshore structure such as an exploration or production platform used for the exploitation of
HEMS - Helicopter emergency medical services
Henry (H). The inductance of a closed circuit in which an electromotive force of 1 volt is produced when the electric current
Hertz (Hz). The frequency of a periodic phenomenon of which the period is 1 second.
HHO - helicopter hoist operation
High energy rotor
‘High energy rotor’ means a rotating component or assembly which, when ruptured, will
Holding bay. A defined area where aircraft can be held, or bypassed, to facilitate efficient surface movement of aircraft.
“holding point” means:
Holding procedure. A predetermined manoeuvre which keeps an aircraft within a specified airspace while awaiting further
Holdover time. The estimated time the anti-icing fluid (treatment) will prevent the formation of ice and frost and the
Homing. The procedure of using the direction-finding equipment
Hot spot. A location on an aerodrome movement area with a history or potential risk of collision or runway incursion, and
Head-up display (HUD). A display system that presents flight information into the pilot’s forward external field of view.
Human capabilities and limitations which have an impact on the safety and efficiency of aeronautical
Hypsometric tints. A succession of shades or colour gradations used to depict ranges of elevation.
Integrated Aeronautical Information Package. A package which consists of the following elements:
International airways volcano watch (IAVW). International arrangements for monitoring and providing warnings to aircraft
‘ICAO’ means International Civil Aviation Organisation.
ICAO Public Key Directory (ICAO PKD). The central database serving as the repository of Document Signer Certificates
Identification beacon. An aeronautical beacon emitting a coded signal by means of which a particular point of reference can
‘IFR conditions’ means weather conditions below the minimum for flight under visual flight rules.
IGA - International General Aviation.
‘ILS’ means instrument landing system.
Immigration control. Measures adopted by States to control the entry into, transit through and departure from their territories
Import duties and taxes
Import duties and taxes. Customs duties and all other duties, taxes or charges, which are collected on or in connection with
Improperly documented person
Improperly documented person. A person who travels, or attempts to travel: (a) with an expired travel document or an
In-flight security officer
In-flight security officer. A person who is authorized by the government of the State of the Operator and the government of the
Inadmissible person. A person who is or will be refused admission to a State by its authorities.
INCERFA. The code word used to designate an uncertainty phase.
Incident. An occurrence, other than an accident, associated with the operation of an aircraft which affects or could affect the
Incompatible Dangerous Goods
Incompatible. Describing dangerous goods which, if mixed, would be liable to cause a dangerous evolution of heat or gas or
Independent parallel approaches. Simultaneous approaches to parallel or near-parallel instrument runways where radar
“Indicated airspeed’ (IAS) means the speed of an aircraft as shown on its pitot static airspeed indicator calibrated to reflect standard atmosphere adiabatic compressible flow at sea level uncorrected for airspeed system errors.
Initial approach segment
Initial approach segment. That segment of an instrument approach procedure between the initial approach fix and the
Instrument approach procedure
Instrument approach procedure. A series of predetermined manoeuvres by reference to flight instruments with specified
Instrument flight time
Instrument flight time. Time during which a pilot is piloting an aircraft solely by reference to instruments and without external
Instrument ground time
Time during which a pilot is practising, on the ground, simulated instrument flight in a flight
Instrument runway. One of the following types of runways intended for the operation of aircraft using instrument approach
Instrument flight time or instrument ground time.
Intermediate approach segment
Intermediate approach segment. That segment of an instrument approach procedure between either the intermediate approach
Intermediate holding position
Intermediate holding position. A designated position intended for traffic control at which taxiing aircraft and vehicles shall
International airport. Any airport designated by the Contracting State in whose territory it is situated as an airport of entry
Interpilot air-to-air communication. Two-way communication
Investigation. A process conducted for the purpose of accident prevention which includes the gathering and analysis of
Investigator-in-charge. A person charged, on the basis of his or her qualifications, with the responsibility for the organization,
Isogonal. A line on a map or chart on which all points have the same magnetic variation for a specified epoch.
Isogriv. A line on a map or chart which joins points of equal angular difference between the North of the navigation grid and
(a) Isolated aerodrome. A destination aerodrome for which there is no destination alternate aerodrome suitable for a given
(b) Isolated aerodrome. If acceptable to the Authority, the destination aerodrome can be considered as an isolated aerodrome,
Joule (J). The work done when the point of application of a force of 1 newton is displaced a distance of 1 metre in the
Joint rescue coordination centre (JRCC). A rescue
Kelvin (K). A unit of thermodynamic temperature which is the fraction 1/273.16 of the thermodynamic temperature of the
Kilogram (kg). The unit of mass equal to the mass of the international prototype of the kilogram.
Knot (kt). The speed equal to 1 nautical mile per hour.
Known consignor. A consignor who originates cargo or mail for its own account and whose procedures meet common security
Lading. The placing of cargo, mail, baggage or stores on board an aircraft to be carried on a flight.
Unlading. The removal of cargo, mail, baggage or stores from an aircraft after a landing.
“landing area” means that part of the movement area intended for the landing or take-off of
Landing direction indicator
Landing direction indicator. A device to indicate visually the direction currently designated for landing and for take-off.
Landing gear extended speed
“Landing gear extended speed’ means the maximum speed at which an aircraft can be safely flown with the landing gear extended.
Landing gear operating speed
‘Landing gear operating speed’ means the maximum speed at which the landing gear can be safely extended or retracted.
‘Large aeroplane’ means an aeroplane of more than 5700 kg (12,500 pounds) maximum certificated take-off weight. The category ‘Large Aeroplane’ does not include the commuter aeroplane category.
Laser-beam critical flight zone (LCFZ). Airspace in the proximity of an aerodrome but beyond the LFFZ where the irradiance
Landing distance available (LDA). The length of runway which is declared available and suitable for the ground run of an
LDIN: Lead-in lighting
Landing decision point (LDP) means the point used in determining landing performance from which, an engine failure having been recognised at this point, the landing may be safely continued or a balked landing initiated.
Lighting system reliability
Lighting system reliability. The probability that the complete installation operates within the specified tolerances and that the
In the context of the medical provisions in Chapter 6, likely means with a probability of occurring that is unacceptable to
Limit loads. The maximum loads assumed to occur in the anticipated operating conditions.
Litre (L). A unit of volume restricted to the measurement of liquids and gases which is equal to 1 cubic decimetre.
‘Load factor’ means the ratio of a specified load to the total weight of the aircraft. The specified load is expressed in terms of any of the following: aerodynamic forces, inertia forces, or ground or water reactions
Location indicator. A four-letter code group formulated in
Lumen (lm). The luminous flux emitted in a solid angle of 1 steradian by a point source having a uniform intensity
Lux (lx). The illuminance produced by a luminous flux of 1 lumen uniformly distributed over a surface of 1 square metre.
Low visibility procedures (LVP) means procedures applied at an aerodrome for the purpose of ensuring safe operations during lower than standard category I, other than standard category II, category II and III approaches and low visibility take-offs
Low visibility take-off (LVTO) means a take-off with an RVR lower than 400 m but not less than 75 m.
‘Mach number’ means the ratio of true air speed to the speed of sound.
Magnetic variation. The angular difference between True North and Magnetic North.
‘Main rotor(s)’ means the rotor or rotors that supply the principal lift to a rotorcraft
MALSF - Medium-intensity Approach Lighting System with Sequenced Flashing lights
MALSR - Medium-intensity Approach Lighting System with Runway Alignment Indicator Lights
‘Manifold Pressure’ piston engines means the absolute static pressure measured at the appropriate point in the induction system, usually in inches or millimetres of mercury.
“manoeuvring area” means that part of an aerodrome used for the take-off, landing and
Missed approach point (MAPt). That point in an instrument approach procedure at or before which the prescribed missed
Author's Note : Turns are not normally made during a go-around before the MAPt
Marker. An object displayed above ground level in order to indicate an obstacle or delineate a boundary.
Master Minimum Equipment list (MMEL)
“Master Minimum Equipment list (MMEL)” means a list established for a particular
Maximum Best Economy Cruising Power Conditions
‘Maximum Best Economy Cruising Power Conditions’ means the crankshaft rotational
Maximum Contingency Powe
NOTES: (1) The performance data are provided be the engine constructor and give the power and/or thrust
a) ‘Maximum Contingency Power and/or Thrust’ means the power and/or thrust identified in
b) ‘Maximum Contingency Power and/or Thrust Rating’ means the minimum test bed
c) ‘Take-off Power and/or Thrust’ means the power and/or thrust identified in the performance
d) ‘Take-off Power and/or Thrust Rating’ means the minimum test bed acceptance power and/or
e) ‘Intermediate Contingency Power and/or Thrust’ means the power and/or thrust identified in
f) ‘Intermediate Contingency Power and/or Thrust Rating’ means the minimum test bed
g) ‘30-Minute Contingency Power’ (applicable to multi-engined helicopters only) means the power
h) ‘30-Minute Contingency Power Rating’ (applicable to multi-engined helicopters only) means
j) ’Maximum Continuous Power and/or Thrust’ means the power and/or thrust identified in the
k) ‘Maximum Continuous Power and/or Thrust Rating’ means the minimum test bed acceptance
Maximum Continuous Power
Power definitions applicable to engines for aeroplanes and helicopters
'Maximum Continuous Power’ means the output shaft power identified in the performance data
Maximum diversion time
Maximum diversion time. Maximum allowable range, expressed in time, from a point on a route to an en-route alternate
Maximum Engine Overspeed
‘Maximum Engine Overspeed’ (20 second-piston engines) means the maximum engine rotational speed, inadvertent occurrence of which for periods of up to 20 seconds, has been agreed not to require rejection of the engine from service or maintenance action (other than to correct the cause).
Maximum Engine Overspeed(s)
‘Maximum Engine Overspeed(s)’ (20 second-turbine engines) means the maximum rotational speed of each mechanically independent main rotating system of an engine, inadvertent occurrence of which for periods of up to 20 seconds, has been agreed not to require rejection of the engine from service or maintenance action (other than to correct the cause). NOTE: For each main rotating system this speed is normally not less than the maximum transient rpm in non-fault conditions.
Maximum Governed Rotational Speed
‘Maximum Governed Rotational Speed’ (variable pitch (governing) propellers) means the maximum
“maximum mass” means the maximum certificated mass of an aircraft (Maximum certificated take-off mass.)
Maximum Permissible Rotational Speed
‘Maximum Permissible Rotational Speed’ (fixed, adjustable or variable (non-governing) pitch
Maximum Power-turbine Overspeed
‘Maximum Power-turbine Overspeed’ (20 second-applicable only to free power-turbine engines for
Maximum Power-turbine Speed for Autorotation
‘Maximum Power-turbine Speed for Autorotation’ (applicable only to free power-turbine engines
Maximum Propeller Overspeed
‘Maximum Propeller Overspeed’ (20 second) means the maximum propeller rotational speed,
Maximum Recommended Cruising Power Conditions
‘Maximum Recommended Cruising Power Conditions’ means the crankshaft rotational
Maximum total mass authorised
“maximum total mass authorised” (MTMA) means the maximum total mass of the aircraft and its contents at which the aircraft may take off in accordance with the certificate of airworthiness in force in respect of the aircraft and the associated flight manual limitations and regulated performance.
Minimum en-route altitude (MEA). The altitude for an en-route segment that provides adequate reception of relevant
Mean power (of a radio transmitter)
Mean power (of a radio transmitter). The average power supplied to the antenna transmission line by a transmitter during an interval of time sufficiently long compared with the lowest frequency encountered in the modulation taken under normal operating conditions.
A = Altimeter Setting
cP = Polar Continental Airmass (Pc also used)
ECMWF = European Centre for Medium Range Weather Forecasts
F = Fahrenheit
g = Acceleraion due to gravity
IC = Ice Crystals
mA = Arctic Maritime Airmass (Am also used)
NLC = Noctilucent Cloud
P = More than
SA = Sand in suspension in the air
TAF = Terminal Aerodrome Forecast (used in aviation reports)
V = Varying
Metadata. Data about data (ISO 19115*).
Metre (m). The distance travelled by light in a vacuum during 1/299 792 458 of a second.
Tonne (t). The mass equal to 1 000 kilograms.
‘Microlight’ is an aeroplane having no more than two seats, Vs,, not exceeding 35 knots (65 KM/h) CAS, and
‘MIL Spec’ means USA Military Specification
Minimum descent altitude/height (MDA/MDH)
Minimum descent altitude (MDA) or minimum descent height (MDH). A specified altitude or height in a non-precision
Minimum Equipment List (MEL)
“Minimum Equipment List (MEL)” means a list which provides for the operation of
Minimum sector altitude
Minimum sector altitude. The lowest altitude which may be used which will provide a minimum clearance of 300 m (1 000 ft)
Mishandled baggage. Baggage involuntarily, or inadvertently, separated from passengers or crew.
Missed approach procedure
Missed approach procedure. The procedure to be followed if the approach cannot be continued.
Mobile surface station
Mobile surface station. A station in the aeronautical telecommunication
Minimum obstacle clearance altitude (MOCA). The minimum altitude for a defined segment of flight that provides the
Mode S subnetwork
Mode S subnetwork. A means of performing an interchange of digital data through the use of secondary surveillance radar
‘Modified Engine’ means an engine, previously approved, in which hitherto unapproved
Mole (mol). The amount of substance of a system which contains as many elementary entities as there are atoms in
Maximum operational passenger seating configuration (MOPSC) means the maximum passenger seating capacity of an individual aircraft, excluding crew seats, established for operational purposes and specified in the operations manual. Taking as a baseline the maximum passenger seating configuration established during the certification process conducted for the type certificate (TC), supplemental type certificate (STC) or change to the TC or STC as relevant to the individual aircraft, the MOPSC may establish an equal or lower number of seats, depending on the operational constraints
MORAs – minimum off route altitudes. There are two types of MORAs – one is called a route MORA and the other is the grid MORA. Because of the imprecise navigation provided by NDBs and the ADFs used in the aeroplanes, the early route MORAs provided an obstacle clearance within 10 nautical miles on both sides of the airways and within a 10-nautical mile radius around the ends of the airways. The 10-nautical mile criterion is with us today. To create the route MORAs today, the enroute chart compilers at Jeppesen analyze the visual aeronautical charts for each respective location around the world to determine the ground elevations below the airways to produce the route MORA for each airway segment.
“movement area” means that part of an aerodrome used for the take-off, landing and
Recommendation.— A mountain wave (MTW) should be considered:
Navigation specification. A set of aircraft and flight crew requirements needed to support performance-based navigation
NCD - No cloud detected
NDV - No directional variation (meteorology)
Near-parallel runways. Non-intersecting runways whose extended centre lines have an angle of convergence/divergence of 15
Newton (N). The force which when applied to a body having a mass of 1 kilogram gives it an acceleration of 1 metre per
The hours between the end of evening civil twilight and the beginning of morning civil twilight or such other period.
“night” means the hours between the end of evening civil twilight and the beginning of
Nautical mile (NM). The length equal to 1 852 metres exactly.
Non-instrument runway. A runway intended for the operation of aircraft using visual approach procedures.
Normal operating differential pressure
‘Normal operating differential pressure’ means the pressure differential between the cabin
The trend forecast shall indicate significant changes in respect of one or more of the elements: surface wind, visibility,
NOTE : Refer to ICAO Annex 3, 2.2 - 2.2.7
NOTAM. A notice distributed by means of telecommunication
SNOWTAM. A special series NOTAM notifying the
'NPA’ means Notice of Proposed Amendment.
N.S.S. - Network Server System
'NTPD’ means normal temperature, pressure, dry, i.e. 2l°C, 760 mmHg and no water vapour.
Aided night vision imaging system (NVIS) flight means, in the case of NVIS operations, that portion of a visual flight rules (VFR) flight performed at night when a crew member is using night vision goggles (NVG);
Obstacle. All fixed (whether temporary or permanent) and mobile objects, or parts thereof, that:
Obstacle clearance altitude
“obstacle clearance altitude (OCA) or obstacle clearance height (OCH)” means the
Obstacle clearance limit (OCL)
“obstacle clearance limit (OCL)” means the height above the elevation of an
Obstacle clearance altitude (OCA) or obstacle clearance height (OCH). The lowest altitude or the lowest height above the
ODALS: Omni directional Approach Lighting System
‘OEI’ means one engine inoperative
Offset frequency simplex
Offset frequency simplex. A variation of single channel
Obstacle free zone (OFZ). The airspace above the inner approach surface, inner transitional surfaces, and balked landing
Ohm (Ω). The electric resistance between two points of a conductor when a constant difference of potential of 1 volt, applied
OIS - Onboard Information Systems
“operational control” means the exercise of authority over the initiation,
Operational control communications
Operational control communications. Communications
Operational flight plan
“operational flight plan” means the operator’s plan for the safe conduct of the flight
“operator” means a person, organisation or enterprise engaged in or offering to
Ornithopter. A heavier-than-air aircraft supported in flight chiefly by the reactions of the air on planes to which a flapping
Orthometric height. Height of a point related to the geoid, generally presented as an MSL elevation.
Overpack. An enclosure used by a single shipper to contain one or more packages and to form one handling unit for
Oxides of nitrogen
Oxides of nitrogen. The sum of the amounts of the nitric oxide and nitrogen dioxide contained in a gas sample calculated as if
1. An approach path indicator system consisting of four sharp cutoff light units situated on the left side of the runway (on both sides of the runway, in the case of the military) in the form of a wing bar.
2. An airport lighting facility, similar to VASI, providing vertical approach slope guidance to aircraft during approach to landing.
Precision approach radar (PAR). Primary radar equipment
pproach radars are designated to
Pascal (Pa). The pressure or stress of 1 newton per square metre.
Passenger amenities. Facilities provided for passengers which are not essential for passenger processing.
Performance Class 1
“Performance Class 1” means, in relation to a helicopter, performance such that, in
Performance Class 2
“Performance Class 2” means, in relation to a helicopter, performance such that in
Performance Class 3
“Performance Class 3” means, in relation to a helicopter, performance such that, in
Simple, evaluative statements on the required outcome of the competency element and a description of
Person with disabilities
Person with disabilities. Any person whose mobility is reduced due to a physical incapacity (sensory or locomotor), an
'PF' means Pilot flying.
Preflight Information Bulletin
Pilot in command
‘Pilot in command’ means the pilot responsible for the operation and safety of an aircraft during
Point of no return. The last possible geographic point at which an aeroplane can proceed to the destination aerodrome as well
Point light. A luminous signal appearing without perceptible length.
Portrayal. Presentation of information to humans (ISO 19117*).
Position (geographical). Set of coordinates (latitude and longitude) referenced to the mathematical reference ellipsoid which
‘Powered sailplane’ means an aircraft, equipped with one or more engines having, with engine(s)
Powered-lift. A heavier-than-air aircraft capable of vertical take-off, vertical landing, and low-speed flight, which depends
Powerplant. The system consisting of all the engines, drive system components (if applicable), and propellers (if installed),
Precision approach procedure. An instrument approach procedure utilizing azimuth and glide path information provided by
Preliminary Report. The communication used for the prompt dissemination of data obtained during the early stages of the
“pressure altitude” means an atmospheric pressure expressed in terms of altitude
Prevailing visibility. The greatest visibility value, observed in accordance with the definition of “visibility”, which is reached
Primary frequency. The radiotelephony frequency assigned to
Primary radar. A radar system which uses reflected radio
“private aircraft” means an aircraft which is neither a commercial transport aircraft
PRMs - Persons with reduced mobility
Problematic use of substances
“problematic use of substances” means the use of one or more psychoactive substances by
Procedure altitude/height. A specified altitude/height flown operationally at or above the minimum altitude/height and
Procedure turn. A manoeuvre in which a turn is made away from a designated track followed by a turn in the opposite direction
“proficiency check” means a demonstration of skill to revalidate or renew a flight
Profile. The orthogonal projection of a flight path or portion
Prognostic chart. A forecast of a specified meteorological element(s) for a specified time or period and a specified surface or
“prohibited area” means airspace of defined dimensions designated by the appropriate
Protected flight zones
Protected flight zones. Airspace specifically designated to mitigate the hazardous effects of laser radiation.
Protected service volume
Protected service volume. A part of the facility coverage where the facility provides a particular service in accordance with
Protection area. An area within a taxi-route and around a helicopter stand which provides separation from objects, the FATO,
PSR blip. The visual indication, in non-symbolic form, on a
“psychoactive substances” means alcohol, opoids, cannabinoids, sedatives and
Public authorities. The agencies or officials of a Contracting State responsible for the application and enforcement of the
Public health emergency
Public health emergency of international concern. An extraordinary event which is determined, as provided in the
Public health risk
Public health risk. A likelihood of an event that may affect adversely the health of human populations, with an emphasis on
Quality assurance. Part of quality management focused on providing confidence that quality requirements will be fulfilled
Radar approach. An approach in which the final approach
Radar clutter. The visual indication on a radar display of
Radar contact. The situation which exists when the radar
Radar identification. The situation which exists when the
Radar monitoring. The use of radar for the purpose of
Radar separation. The separation used when aircraft position
Radar track position
Radar track position. An extrapolation of aircraft position by
Radian (rad). The plane angle between two radii of a circle which cut off on the circumference an arc equal in length to the
Radio navigation service
Radio navigation service. A service providing guidance information or position data for the efficient and safe operation of
RAIL: Runway Alignment Indicator Lights
Receiver autonomous integrity monitoring
1) A technique whereby a civil GNSS receiver / processor determines the integrity of the GNSS navigation signals without reference to senders or non-DoD integrity systems other than the receiver itself. This determination is achieved by consistency check among redundant pseudorange measurements.
2) A form of ABAS whereby a GNSS receiver processor determines the integrity of the GNSS navigation signals using only GPS signals or GPS signals augmented with altitude (baroaiding). This determination is achieved by a consistency check among redundant pseudo-range measurements.
Rated thrust. For engine emissions purposes, the maximum take-off thrust approved by the certificating authority for use under
Required communication performance (RCP). A statement of the performance requirements for operational communication
Readback. A procedure whereby the receiving station repeats
Reference landing speed
‘Reference landing speed’ (Vref) means the speed of the aeroplane, in a specified landing configuration,
Reference pressure ratio
Reference pressure ratio. The ratio of the mean total pressure at the last compressor discharge plane of the compressor to the
Regular station. A station selected from those forming an enroute
Regulated agent. An agent, freight forwarder or any other entity who conducts business with an operator and provides security
REIL: Runway End Identification Lights
Rejected take-off (RTO) area
Rejected take-off (RTO) area. A defined area on a heliport suitable for helicopters operating in performance class 1 to complete a
Release of goods
Release of goods. The action by the customs authorities to permit goods undergoing clearance to be placed at the disposal of
Relief. The inequalities in elevation of the surface of the Earth represented on aeronautical charts by contours, hypsometric tints,
Relief flights. Flights operated for humanitarian purposes which carry relief personnel and relief supplies such as food,
Removal of a person
Removal of a person. Action by the public authorities of a State, in accordance with its laws, to direct a person to leave that
Removal order. A written order served by a State on the operator on whose flight an inadmissible person travelled into that
“repair” means the restoration of an aeronautical product to an airworthy condition
Repetitive flight plan
“repetitive flight plan” means a flight plan related to a series of frequently recurring,
Reporting point. A specified (named) geographical location in relation to which the position of an aircraft can be reported.
Required navigation performance
“required navigation performance” (RNP) means a statement of the navigation
Runway end safety area (RESA). An area symmetrical about the extended runway centre line and adjacent to the end of the
Rescue. An operation to retrieve persons in distress, provide
Rescue coordination centre
Rescue coordination centre (RCC). A unit responsible for promoting efficient organization of search and rescue services and for
Rescue subcentre (RSC). A unit subordinate to a rescue
Resolution. A number of units or digits to which a measured or calculated value is expressed and used.
“rest period” means any period of time on the ground during which a flight crew
“restricted area” means an airspace of defined dimensions designated by the appropriate
Reversal procedure. A procedure designed to enable aircraft to reverse direction during the initial approach segment of an
Rigger's Angle is another name for the Angle of Incidence.
Risk assessment. An assessment by a deporting State of a deportee’s suitability for escorted or unescorted removal via
Risk management. The systematic application of management procedures and practices which provide border inspection
RMZ - Radio Mandatory Zone
‘Rotational Speed’ (engine) means, unless otherwise qualified (e.g. propeller rotational speed), the
‘Rotorcraft’ means a heavier-than-air aircraft that depends principally for its support in flight on the
'Rotorcraft-load combination’ means the combination of a rotorcraft and an external-load,
Radar position indication (RPI). The visual indication, in
'rpm’ means revolutions per minute.
Radar position symbol (RPS). The visual indication, in
Runway guard lights
Runway guard lights. A light system intended to caution pilots or vehicle drivers that they are about to enter an active runway.
Runway strip. A defined area including the runway and stopway, if provided, intended:
Runway turn pad
Runway turn pad. A defined area on a land aerodrome adjacent to a runway for the purpose of completing a 180-degree turn on
Runway visual range
“runway visual range” (RVR) means the range over which the pilot of an aircraft on
“runway-holding position” means a designated position intended to protect a runway, an
Safe forced landing
“safe forced landing” means an unavoidable landing or ditching with a reasonable
Safety recommendation. A proposal of an accident investigation authority based on information derived from an investigation,
Safety sensitive personnel
“safety sensitive personnel” means persons who might endanger aviation safety if they
‘Sailplane’ means a heavier-than-air aircraft that is supported in flight by the dynamic reaction of the
SALS - Short Approach Lighting System
Standard and Recommended Practices
Satisfactory evidence. A set of documents or activities that a Contracting State accepts as sufficient to show compliance with
S.C.I. - Secure Communication Interface
SCPs - Special category of passenger(s) Persons requiring special conditions, assistance and/or devices when carried on a flight shall be considered as SCPs
Screening. The application of technical or other means which are intended to identify and/or detect weapons, explosives or
Search and rescue (SAR) service
Search and rescue (SAR) service. The performance of distress
Search and rescue region (SRR). An area of defined dimensions,
Search and rescue aircraft
Search and rescue (SAR) aircraft. An aircraft provided with
Search and rescue services unit
Search and rescue services unit. A generic term meaning, as the case may be, rescue coordination centre, rescue subcentre or
Second(s). The duration of 9 192 631 770 periods of the radiation corresponding to the transition between the two hyperfine
Security. Safeguarding civil aviation against acts of unlawful interference. This objective is achieved by a combination of
Security equipment. Devices of a specialized nature for use, individually or as part of a system, in the prevention or detection
Security restricted area
Security restricted area. Those areas of the airside of an airport which are identified as priority risk areas where in addition to
Segregated parallel operations
Segregated parallel operations. Simultaneous operations on parallel or near-parallel instrument runways in which one runway
“SELCAL” means a system which permits the selective calling of individual aircraft over
Self-sustaining powered sailplane
Self-sustaining powered sailplane. A powered aeroplane with available engine power which allows it to maintain level flight
Serious incident. An incident involving circumstances indicating that there was a high probability of an accident and associated
Serious injury. An injury which is sustained by a person in an accident and which:
Shipboard heliport. A heliport located on a ship that may be purpose or non-purpose-built. A purpose-built shipboard heliport
Shoulder. An area adjacent to the edge of a pavement so prepared as to provide a transition between the pavement and the
Siemens (S). The electric conductance of a conductor in which a current of 1 ampere is produced by an electric potential
Sievert (Sv). The unit of radiation dose equivalent corresponding to 1 joule per kilogram.
SIGMET information. Information issued by a meteorological watch office concerning the occurrence or expected
“signal area” means an area on an aerodrome used for the display of ground signals
Significant point. A specified geographical location used in defining an ATS route or the flight path of an aircraft and for other
SLOP - Strategic Lateral Offset Procedure
Slotted aloha. A random access strategy whereby multiple users access the same communications channel independently, but
Slush. Water-saturated snow which with a heel-and-toe slap- down motion against the ground will be displaced with a splatter;
Smoke. The carbonaceous materials in exhaust emissions which obscure the transmission of light.
Smoke Number. The dimensionless term quantifying smoke emissions (see 3 of ICAO Annex 16, Appendix 2).
Snow (on the ground).
SSALF - Simplified Short Approach Lighting System with Sequenced Flashing Lights
SSALR - Simplified Short Approach Lighting System with Runway Alignment Indicator Lights
SSALS - Simplified Short Approach Lighting System
SSR response. The visual indication, in non-symbolic form,
Standard isobaric surface
Standard isobaric surface. An isobaric surface used on a worldwide basis for representing and analysing the conditions in
State of Design
State of Design. The State having jurisdiction over the organization responsible for the type design.
State of Manufacture
State of Manufacture. The State having jurisdiction over the organization responsible for the final assembly of the aircraft.
State of registry
“state of registry” means the state on whose register the aircraft is entered;
Note.— In the case of the registration of aircraft of an international operating agency on other than a national basis, the
State of the operator
“state of the operator” means the state in which the operator’s principal place of
Static load-bearing surface
Static load-bearing surface. A surface capable of supporting the mass of a helicopter situated upon it.
Station declination. An alignment variation between the zero degree radial of a VOR and true north, determined at the time the
Steradian (sr). The solid angle which, having its vertex in the centre of a sphere, cuts off an area of the surface of the sphere
‘Stopway’ means an area beyond the take-off runway, no less wide than the runway and centred
Stores (Supplies). a) Stores (supplies) for consumption; and b) Stores (supplies) to be taken away.
‘STPD’ means standard temperature, pressure, dry, i.e. O°C, 760 mmHg and no water vapour.
Subsonic aeroplane. An aeroplane incapable of sustaining level flight at speeds exceeding flight Mach number of 1.
‘Supplemental oxygen’ means the additional oxygen required to protect each occupant against the
Switch-over time (light). The time required for the actual intensity of a light measured in a given direction to fall from 50 per
Synthetic training device (STD)
“synthetic training device (STD)” means any one of the following types of
(a) a synthetic training device which provides accurate representation of the
(b) a flight procedures simulator which provides a realistic flight-deck
(c) a basic instrument flight trainer which is equipped with appropriate
Terminal arrival altitude (TAA). The lowest altitude that will provide a minimum clearance of 300 m (1 000 ft) above all
Power definitions applicable to engines for aeroplanes and helicopters
‘Take-off Power’ means the output shaft power identified in the performance data for use during
Take-off Power Rating
Power definitions applicable to engines for aeroplanes and helicopters
‘Take-off Power Rating’ means the test bed minimum acceptance output shaft power as stated
Take-off safety speed
“Take-off safety speed’ (V2) means a referenced airspeed obtained after lift-off at which the required
Target level of safety (TLS)
“target level of safety (TLS)“ means a generic term representing the level of risk
Taxi/ground idle. The operating phases involving taxi and idle between the initial starting of the propulsion engine(s) and the
“taxiing” means the movement of an aircraft on the surface of an aerodrome under its own
“taxiway” means a defined path on a land aerodrome established for the taxiing of aircraft
A defined path on a land aerodrome established for the taxiing of aircraft and intended to provide a link between one
Tropical cyclone advisory centre (TCAC). A meteorological centre designated by regional air navigation agreement to
Time division multiplex (TDM). A channel sharing strategy in which packets of information from the same source but with
Time division multiple access (TDMA). A multiple access scheme based on time-shared use of an RF channel employing:
‘TDP’ with respect to rotorcraft means take-off decision point.
“Technical Instructions” means the Technical Instructions for the Safe Transport of
Technical Instructions Dangerous Goods
Technical Instructions. The Technical Instructions for the Safe Transport of Dangerous Goods by Air (Doc 9284), approved
Temporary admission. The customs procedure under which certain goods can be brought into a customs territory
Terminal control area
“terminal control area” means a control area normally established by the appropriate ATS
Terms associated with probabilities
Terms associated with probabilities (for engines):-
Terrain. The surface of the Earth containing naturally occurring features such as mountains, hills, ridges, valleys, bodies of
Tesla (T). The magnetic flux density given by a magnetic flux of 1 weber per square metre.
Threshold time. The range, expressed in time, established by the State of the Operator, to an en-route alternate aerodrome,
Through-flight. A particular operation of aircraft, identified by the operator by the use throughout of the same symbol, from
Touchdown and lift-off area (TLOF). A load bearing area on which a helicopter may touch down or lift off.
TMZ - Transponder Mandatory Zone
Total cosmic radiation
“total cosmic radiation” means the total of ionising and neutron radiation of galactic
Total vertical error (TVE)
“total vertical error (TVE)” means the vertical geometric difference between the
Touchdown zone. The portion of a runway, beyond the threshold, where it is intended landing aeroplanes first contact the
Traffic avoidance advice
“traffic avoidance advice” means advice provided by an air traffic services unit specifying
“traffic information” means information issued by an air traffic services unit to alert a pilot
Traffic information service – broadcast
Traffic information service – broadcast (TIS-B) IN. A surveillance function that receives and processes surveillance data from
Transfer of control point
Transfer of control point. A defined point located along the flight path of an aircraft, at which the responsibility for
Transit delay. In packet data systems, the elapsed time between a request to transmit an assembled data packet and an
“transition altitude” means the altitude above which the vertical position of an
“transition level” means the altitude below which the vertical position of an
Travel document. A passport or other official document of identity issued by a State or organization, which may be used by
Tributary station. An aeronautical fixed station that may route receive or transmit messages and/or digital data but which does not relay except for the purpose of serving similar
When an AIP Amendment or an AIP Supplement is published in accordance with AIRAC procedures, a “trigger” NOTAM is originated and promulgated. The intent of this NOTAM is to serve as a reminder in the pre-flight information bulletin (PIB) by signalling the coming into effect of operationally significant permanent or temporary changes to the AIP, thus ensuring that users are aware of changes that may affect their flights. It also serves as a reminder to AIS officers responsible for updating AIP to insert a new AIP Amendment or AIP Supplement in the affected AIP on the amendment or supplement effective date.
Tropical cyclone. Generic term for a non-frontal synoptic-scale cyclone originating over tropical or sub-tropical waters with
‘True airspeed’ means the airspeed of an aircraft relative to undisturbed air. True airspeed is equal
‘TSO’ means Technical Standard Order.
Type Certificate. A document issued by a Contracting State to define the design of an aircraft type and to certify that this
Ultimate load. The limit load multiplied by the appropriate factor of safety.
UN number. The four-digit number assigned by the United Nations Committee of Experts on the Transport of Dangerous
Unaccompanied baggage. Baggage that is transported as cargo and may or may not be carried on the same aircraft with the
Unburned hydrocarbons. The total of hydrocarbon compounds of all classes and molecular weights contained in a gas sample,
Unclaimed baggage. Baggage that arrives at an airport and is not picked up or claimed by a passenger.
Unidentified baggage. Baggage at an airport, with or without a baggage tag, which is not picked up by or identified with a
Unit load device
Unit load device (ULD). Any type of freight container, aircraft container, aircraft pallet with a net, or aircraft pallet with a net over an
Upper-air chart. A meteorological chart relating to a specified upper-air surface or layer of the atmosphere.
Usability factor. The percentage of time during which the use of a runway or system of runways is not restricted because of the
‘VF1’ means the design flap speed for procedure flight conditions.
'VFTO’ means final take-off speed.
‘VLO’ means maximum landing gear operating speed.
VS’ means the stall speed or the minimum steady flight speed at which the aeroplane is controllable.
‘VTOSS’ means take-off safety speed for Category A rotorcraft.
'VY' means speed for best rate of climb.
'VA’ means design manoeuvring speed.
Volcanic ash advisory centre (VAAC). A meteorological centre designated by regional air navigation agreement to provide
Variable Pitch Propellers
'Variable Pitch Propellers’ means a propeller, the pitch setting of which changes or can be changed,
b) A propeller, the pitch setting of which is controlled by a governor or other automatic means
VASI TVASI T-VASI
Visual Approach Slope Indicator, and TVASI (T-VASI)
'VB’ means design speed for maximum gust intensity.
'VC’ means design cruising speed.
'VD/MD’ means design diving speed.
VHF digital link (VDL). A constituent mobile subnetwork of the aeronautical telecommunication network (ATN), operating
VDF/MDF’ means demonstrated flight diving speed.
Vectoring. Provision of navigational guidance to aircraft in the form of specific headings, based on the use of an ATS
‘VEF' means the speed at which the critical engine is assumed to fail during take-off.
‘VF' means design flap speed.
“visibility” for aeronautical purposes is the greater of:
Visitor. Any person who disembarks and enters the territory of a Contracting State other than that in which that person
Visual approach procedure
Visual approach procedure. A series of predetermined manoeuvres by visual reference, from the initial approach fix, or where
VOLMET. Meteorological information for aircraft in flight.
Volt (V). The unit of electric potential difference and electromotive force which is the difference of electric potential between
‘VSR’ means reference stall speed.
World area forecast centre (WAFC). A meteorological centre designated to prepare and issue significant weather forecasts
World area forecast system (WAFS). A worldwide system by which world area forecast centres provide aeronautical
Watt (W). The power which gives rise to the production of energy at the rate of 1 joule per second.
“way-point” means a specified geographical location used to define an area navigation
Weber (Wb). The magnetic flux which, linking a circuit of one turn, produces in it an electromotive force of 1 volt as it is
A runway is considered wet when the runway surface is covered with water, or equivalent, less than
Winching area. An area provided for the transfer by helicopter of personnel or stores to or from a ship.
Waypoint. A specified geographical location used to define an area navigation route or the flight path of an aircraft employing
Fly-by waypoint. A waypoint which requires turn anticipation to allow tangential interception of the next segment of a
Z marker beacon
Z marker beacon. A type of radio beacon, the emissions of which radiate in a vertical cone-shaped pattern.