AAIM: Aircraft Autonomous Integrity Monitoring. Provides integrity monitoring of the GPS solution by using information from additional on-board systems (e.g. barometric altimeter and/or inertial navigation system).
ABAS: Aircraft Based Augmentation System. An augmentation system that augments and/or integrates the information obtained from the other GNSS elements with information available on board the aircraft.
Note: ABAS is most commonly used to support integrity monitoring. There are two general classes of integrity monitoring: receiver autonomous integrity monitoring (RAIM), which uses GNSS information exclusively, and aircraft autonomous integrity monitoring (AAIM), which uses information from additional on-board systems (e.g. barometric altimeter and inertial navigation system (INS)).
ACC: Air Traffic Control Centre. A centre providing an ATC service for the purpose of preventing collisions: a) between aircraft; and b) expediting and maintaining an orderly flow of air traffic.
ADS: Automatic Dependent Surveillance. A surveillance technique in which aircraft automatically provide, via a data link, data derived from on-board navigation and position-fixing system, including aircraft identification, four-dimensional position, and additional data as appropriate.
ADS-B: Automatic Dependent Surveillance-Broadcast. A function on an aircraft that periodically broadcasts its state vector (horizontal and vertical position, horizontal and vertical velocity) and other information.
ADS-C: Automatic Dependent Surveillance-Contract. Similar to ADS-B, but with the data transmission based on a contract between a ground system and the aircraft.
AIP: Aeronautical Information Publication. Static information, updated every 28 days, containing information essential to air navigation.
AIRAC: Aeronautical Information Regulation and Control. An acronym signifying a system aimed at advance notification based on common effective date.
Airspace Concept: An Airspace Concept provides the outline and intended framework of operations within an airspace. An Airspace Concept is essentially a high-level statement of an airspace plan. Airspace Concepts redeveloped to satisfy explicit t strategic objectives such as improved safety, increased air traffic capacity and mitigation of environmental impact etc. Airspace Concepts include details of the practical organisation of the airspace and its users based on particular CNS/ATM assumptions. e.g. ATS route structure, separation minima, route spacing and obstacle clearance.
ANSP: Air Navigation Service Provider. A body that manages aviation related traffic in a block of airspace on behalf of a company, region or country. A region may be multinational.
AO: Aircraft Operator. One who operates an aircraft.
AOB: Angle Of Bank.
AP: Autopilot. An autopilot is a mechanical, electrical, or hydraulic system used to guide an aircraft without human assistance. When AP is selected, steering information, calculated by the navigation computer, is transmitted to a flight control system to guide the aircraft. This information is also displayed on the pilot's Primary Flight Display (PFD).
APP: Approach Control Unit. An unit established to provide an ATC service to controlled flights arriving at, or departing from, one or more aerodromes.
APV: Approach Procedure with Vertical Guidance. An instrument procedure which utilizes lateral and vertical guidance but does not meet the requirements established for precision approach and landing operations.
Area Navigation: A method of navigation which permits aircraft operation on any desired flight path within the coverage of station-referenced navigation aids or within the limits of the capability of self-contained aids, or a combination of these.
Note.- Area navigation includes performance based navigation as well as other RNAV operations that do not meet the definition of performance based navigation.
ARINC: Aeronautical Radio Inc. (USA).
ATC: Air Traffic Control. A service operated by an appropriate authority to promote the safe, orderly and expeditious flow of air traffic.
ATM: Air Traffic Management. The interactions between multiple human operators, procedures and technical systems whilst providing an air traffic service.
ATS: Air Traffic Services. A generic term meaning: Flight Information Service; Alerting Service; Air Traffic Advisory Service; and Air Traffic Control Service (Area, Approach, and Airport).
ATS surveillance service: 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 enables the identification of aircraft.
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.
Area navigation route. An ATS route established for the use of aircraft capable of employing area navigation.
Baro-VNAV. Barometric Vertical Navigation.
B-RNAV: Basic Area Navigation. Mandated in European airspace in April 1998, this navigational application is exactly the same as RNAV5. B-RNAV operations require the aircraft to fly +/-5NM either side of the ATS route centreline 95% of the flight time.
CDFA: Continuous Descent Final Approach. A technique, consistent with stabilised approach procedures, for flying the Final Approach segment of a non precision approach as a continuous descent without level off to a point approximately 15m (50’) above the point where the flare manoeuvre should begin for the aircraft flown.
CDI: Course Deviation Indicator. An avionics display used in aircraft navigation to show the aircraft position relative to a defined track or radial.
CDU: Control and Display Unit. The primary interface and input device for Flight Management System operations.
CFIT: Controlled Flight Into Terrain. An accident in which an airworthy and serviceable aircraft, under complete control of the pilot(s), inadvertently flies into terrain, an obstacle, or water.
CNS: Communications, Navigation and Surveillance. This includes all communication facilities, navigation services and surveillance systems.
COM: Communications. A process by which information is exchanged between or among individuals and/or machines.
CPDLC: Controller–Pilot Data Link Communications. A means of communication between controller and pilot, using data link for ATC communications.
CRC: Cyclic Redundancy Checking. A mathematical algorithm applied to the digital expression of data that provides a level of assurance against loss or alteration of data.
CRM: Collision Risk Modelling. The use of mathematical models to determine the risk of collision in air traffic taking account of all relevant elements including the traffic density, the route structure, the percentage of aircraft climbing, descending and in level flight, the ATM environment, the available tools and the interactions between the different elements.
CVSM: Conventional Vertical Separation Minima. The vertical separation required between aircraft is 2000ft above FL290 and 1000ft below FL 290.
DA: Decision Altitude. A specific altitude in the precision approach (PA) or Approach with Vertical guidance (APV) at which a missed approach must be initiated if the required visual references to continue the approach have not been established. DA is referenced to Mean Sea Level (MSL).
DH: Decision Height. A specific altitude in the precision approach (PA) or Approach with Vertical guidance (APV) at which a missed approach must be initiated if the required visual references to continue the approach have not been established. DH is referenced to the threshold elevation.
DME: Distance Measuring Equipment. A transponder-based radio navigation technology that measures distance by timing the propagation delay of VHF or UHF radio signals.
DOP: Dilution of Precision. Is the measure of ‘quality’ of the geometry of multiple navigational signals, as seen by the observer, used to estimate the position. A 90° angle subtended at the user will give the most accurate position estimation and is indicated with a low DOP value. A high DOP value indicates a poor level of positional accuracy.
EASA: European Aviation Safety Authority. A European Agency responsible for drafting aviation safety legislation; ensuring uniform implementation of that legislation; providing type certification of aircraft, engines and parts; providing world-wide approval and safety oversight of aircraft design, production and maintenance organisations outside the EU; licensing of crews in member states (2008); certification of non-member state airlines (2008) and maintaining rules and procedures for civil aviation operations.
ECAC: European Civil Aviation Conference. Established to promote the continued development of a safe, efficient and sustainable European air transport system.
EUROCAE: European Organization for Civil Aviation Equipment. Established for the design and production of standards, technical specifications and other documents, which are used as the basis for European National Airworthiness Authorities regulations to the benefit of the aviation community as a whole.
EUROCONTROL: European Organisation for the Safety of Air Navigation. A civil and military Organisation which develops, coordinates and plans for implementation of short-, medium- and long-term pan-European air traffic management strategies.
FAA: Federal Aviation Administration. The United States of America’s Aviation Authority.
FAF: Final Approach Fix. A point in space used to indicate the position at which an aircraft should be stabilised with the appropriate guidance for the Final Approach.
FAS: Final Approach Segment. That segment of an instrument approach procedure in which alignment and descent for landing are accomplished.
Fault-free: The fault-free system is assumed to be a system with nominal accuracy and time-to-alert performance. Such a system is assumed to have no failures that affect the integrity, availability and continuity performance.
FD: Flight Director. When FD is selected, steering information (calculated by the AP using data derived from the Navigation Computer) is displayed on the pilot's Primary Flight Display (PFD), but manual control of the aircraft is required to follow the path.
FD: Fault Detection. A point in space used to indicate the position at which an aircraft should be stabilised with the appropriate guidance for the Final Approach.
FDE: Fault Detection and Exclusion. A GPS receiver processing technique which provides, with sufficient visible satellites and adequate geometry, for the identification of a satellite in error and the exclusion of it from position determination.
FDPS: Flight Data Processing System. A system which processes flight plan requests.
FLY-BY waypoints: Where the navigation system anticipates the turn onto the next route leg.
FLY-OVER waypoints: Where the aircraft overflies the waypoint before starting to turn onto the next route leg.
FMS: Flight Management System
An integrated system, consisting of airborne sensor, receiver and computer with both navigation and aircraft performance databases, which provides performance and RNAV guidance to a display and automatic flight control system.
FRT: Fixed Radius Transition. A turn at a waypoint in the en-route phase of flight using a fixed turn radius of either 22.5 NM for high altitudes (FL200 and above), or 15 NM, for low altitudes (FL190 and below).
FTE: Flight Technical Error. The accuracy with which the aircraft is controlled as measured by the indicated aircraft position with respect to the indicated command or desired position. It does not include blunder errors.
FUA: Flexible Use of Airspace. Usage of the airspace by different airspace users for different activities (for example: military airspace which can be released for civil use when not active).
GBAS: Ground Based Augmentation System. A safety-critical system that augments the GPS Standard Positioning Service (SPS) and provides enhanced levels of service.
GLONASS: Global Navigation Satellite System. (Russian System). A satellite navigation system operated by Russian government.
GNSS: Global Navigation Satellite System. A generic name for satellite navigation systems and their augmentations.
GPS: Global Positioning System. (American System). A satellite navigation system operated by the US government.
Hotword: An underlined word on a computer screen, which, when selected (by clicking the mouse on it) will display that word, and an explanation for it, in the glossary.
ICAO: International Civil Aviation Organization. The United Nations agency for civil aviation.
IFP: Instrument Flight Procedure. A description of a series of predetermined flight manoeuvres by reference to flight instruments, published by electronic and/or printed means.
IFR: Instrument Flight Rules. A set of regulations and procedures for flying aircraft without the assumption that pilots that can see and avoid obstacles, terrain and other air traffic.
ILS: Instrument Landing System
INCDU: Inertial Navigation Control Display Unit. Inertial Navigation Control and Display Unit. Enables the aircrew to input current position and control the inertial platform. It displays a continuous readout of current position if operating correctly.
INS: Inertial Navigation System. An aircraft on-board self-contained navigation system. (Requires no external position information.)
IRS: Inertial Reference System. Provides position information for use by an RNAV or FMS system providing either stand alone position input or to mix with radio position data.
IRU: Inertial Reference Unit. A type of inertial sensor which uses only gyroscopes to determine a moving aircrafts change in angular direction over a period of time.
ITRF: International Terrestrial Reference Frame. Represents the realisation of the International Terrestrial Reference System.
JAA: Joint Aviation Authorities. NOW DISBANDED. Was an associated body of the European Civil Aviation Conference (ECAC) representing the civil aviation regulatory authorities of a number of European States who have agreed to co-operate in developing and implementing common safety regulatory standards and procedures. JAA responsibilities have been transferred to EASA.
LNAV: Lateral Navigation. The provision of area navigation guidance in the horizontal plane.
LPV: Localiser Performance with Vertical guidance.
MCDU: Multi-Function Control and Display Unit. Part of the Flight Management System.
MDA: Minimum Decision Altitude.
MDH: Minimum Decision Height.
MEL: Minimum Equipment List. An MEL is a document approved by the regulator that contains the conditions under which a specified aircraft may operate, with particular items of equipment inoperative, at the time of dispatch. It provides a time interval for the rectification of the faulty item, relevant to the operational significance of the item. This document is carried on board the aircraft and provides the Pilot In Command with clear guidance to make an informed decision as to whether the particular flight should or should not proceed.
MFA: Minimum Flight Altitude: An altitude determined to provide a minimum clearance above the controlling obstacle located within the areas concerned.
Mixed Navigation Environment: An environment where different navigation specifications may be applied within the same airspace (e.g. RNAV 5 routes and RNAV 1 routes in the same airspace) or where operations using conventional navigation are allowed together with RNAV or RNP applications.
MNPS: Minimum Navigation Performance Specification. A set of standards which require aircraft to have a minimum navigation performance capability in order to operate in MNPS designated airspace. In addition, aircraft must be certified by their State of Registry for MNPS operation.
MOC: Minimum Obstacle Clearance. The minimum altitude for a defined segment that provides the required obstacle clearance.
MRVA:Minimum Radar Vectoring Altitude.
MSA:Minimum Sector Altitude.
NAVAID: Navigation Aid(s). Any visual or electronic device airborne or on the surface which provides point-to-point guidance information or position data to aircraft in flight.
Navigation Aid (NAVAID) Infrastructure: Navaid Infrastructure refers to space-based and or ground-based navigation aids available to meet the requirements in the navigation specification.
Navigation Application: The application of a navigation specification and the supporting navaid infrastructure, to routes, procedures, and/or defined airspace volume, in accordance with the intended airspace concept.
Note: The navigation application is one element, along with, communication, surveillance and ATM procedures meeting the strategic objectives in a defined airspace concept.
Navigation Function: The detailed capability of the navigation system (such as the execution of leg transitions, parallel offset capabilities, holding patterns, navigation databases) required to meet the Airspace Concept.
Note: Navigational functional requirements are one of the drivers for selection of a particular Navigation Specification. Navigation functionalities (functional requirements) for each Navigation Specification can be found in Volume II, Parts B and C.
Navigation Specification: A Navigation Specification is a set of aircraft and air crew requirements needed to support Performance Based Navigation operations within a defined airspace. Note: There are two kinds of navigation specification: RNAV and RNP. A RNAV specification does not include requirements for on-board performance monitoring and alerting. A RNP specification includes requirements for on-board performance monitoring and alerting.
See the Performance Based Navigation Manual (Doc 9613) Volume II for Navigation Specifications.
ND: Navigation Display. The display found in the cockpit of an aircraft on which all information pertinent to the flight of the aircraft is recorded and displayed.
NDB: Non Directional Beacon. An L/MF or UHF radio beacon transmitting non directional signals whereby the pilot of an aircraft equipped with direction finding equipment can determine his/her bearing to or from the radio beacon and "home" on or track to or from the station.
NPA: Non-Precision Approach. An instrument approach procedure which utilises lateral guidance but does not utilise vertical guidance.
NSE: Navigation System Error. The difference between true position and estimated position. This is sometimes also referred to as Position Estimation Error (PEE). A combination of path definition error, position estimation error and display error
On-board Performance monitoring and alerting: The airborne capability that ensures the integrity of the position estimation is sufficient for the required operation.
PA: Precision Approach.
PANS-OPS: Procedures for Air Navigation Services Aircraft Operations. An ICAO manual Doc 8168.
PARALLEL OFFSET: A desired track parallel to and left or right of the 'parent' track specified in nautical miles of off-set distance.
PBN: Performance Based Navigation. Area Navigation based on performance requirements for aircraft operating along an ATS route, on an instrument approach procedure or in a designated airspace.
Note: Performance requirements are defined in Navigation Specifications in terms of accuracy, integrity, continuity, availability and functionality needed for the proposed operation in the context of a particular airspace concept.Doc 9613), Volume II for Navigation Specifications.
PDE: Path Definition Error. The difference between the defined path and the desired path at a specific point.
PEE: Positioning Estimation Error. The difference between true position and estimated position. This is also referred to as Navigation Sensor Error (NSE).
PRNAV: Precision Area Navigation.
Procedural control: Air traffic control service provided by using information derived from sources other than an ATS surveillance system.
PSE: Path Steering Error. The difference between estimated position and defined path for the aircraft to fly (not including blunder errors). This is also referred to as Flight Technical Error (FTE).
RAIM: Receiver Autonomous Integrity Monitoring. A technique whereby a civil GNSS receiver/processor determines the integrity of the GNSS navigation signals without reference to sensors or integrity systems other than the receiver itself. This determination is achieved by a consistency check among redundant pseudo-range measurements.
RF: Radius to Fix. An ARINC 424 path terminator which defines a turn between two waypoints in the terminal/approach phase of flight using a constant turn radius commensurate with the maximum ground speed and the maximum allowable bank angle. The inbound and outbound legs are tangential to the arc.
RNAV Application: The use of an RNAV specification to meet the requirements of an Airspace Concept.
RNAV Operations: Aircraft operations using an area navigation system for RNAV applications. RNAV operations include the use of area navigation for operations which are not developed in accordance with the PBN Manual.
RNAV Route: An ATS Route established for the use of aircraft adhering to a prescribed RNAV Specification.
RNAV Specification: A navigation specification designation that does not include requirements for on-board performance monitoring and alerting.
RNAV System: A navigation system which permits aircraft operation on any desired flight path within the coverage of station-referenced navigation aids or within the limits of the capability of self-contained aids, or a combination of these. A RNAV system may be included as part of a Flight Management System (FMS).
RNP: Required Navigation Performance. Historically, a statement of the navigational performance necessary for operation within a defined airspace. In the context of PBN, RNP is deemed to denote the requirement for on-board monitoring and alerting of navigation performance.
RNP Application: The use of an RNP specification to meet the requirements of an Airspace Concept.
RNP Route: An ATS Route established for the use of aircraft adhering to a prescribed RNP Specification.
RNP Specification: A navigation specification designation that includes requirements for on-board performance monitoring and alerting
RNP System: An area navigation system which supports on-board performance monitoring and alerting.
ROC: Required Obstacle Clearance. The necessary minimum altitude for a defined segment to ensure safe clearance from terrain and obstacles.
RTCA: Radio Technical Commission on Aeronautics. A not-for-profit corporation that develops consensus-based recommendations for CNS/ATM system issues.
RTF: Radio Telephony. A form of radiocommunications primarily intended for the exchange of information in the form of speech.
SARPS:ICAO Standard And Recommended Practices.
SBAS: Space Based Augmentation System. A wide coverage augmentation system in which the user receives augmentation from a satellite-based transmitter.
SID: Standard Instrument Departure. A designated instrument flight rule (IFR) departure route linking the aerodrome or a specified runway of the aerodrome with a specified significant point, normally on a designated ATS route, at PANS-OPS, Vol II, which the en-route phase of a flight commences.
SIS: Signals In Space
STAR: Standard Terminal Arrival Route. A designated instrument flight rule (IFR) arrival route linking a significant point, normally on an ATS route, with a point from which a published instrument approach procedure can be commenced.
SUR: Surveillance - refers to the ATS Surveillance system.
TACAN: TACtical Air Navigation. The military NAVAID providing bearing and range information. Similar to VOR/DME but TACAN operates in the UHF range.
TAS: True Air Speed.
TLS: Target Level of Safety. The level of safety which a total system is designed to meet.
TOAC: Time Of Arrival Conrol. Arrival time achieved using the aircraft’s on-board systems to meet a Required Time of Arrival (RTA).
TOGA: Take Off/Go Around.
TWR: Tower (Air Traffic Control).
TSE: Total System Error. The difference between the true position and desired position of the aircraft. This error is the sum of the navigation system error, flight technical error and path definition error.
VFR: Visual Flight Rules.
VNAV: Vertical Navigation. The provision of guidance for Vertical Navigation.
VOR: Very High Frequency Omni-Range. A ground-based electronic navigation aid transmitting very high frequency navigation signals, 360 degrees in azimuth, oriented from magnetic north.
VPA: Vertical Path Angle. Angle of the published final approach descent in baro-VNAV procedures.
WGS84: World Geodetic System 84. The coordinate system which is adopted by ICAO for aviation use. It is the reference system used by GPS.