PCAA Navigation key terms

ICAO Annex containing standards and recommended practices for aerodrome design and operations, including runway dimensions, obstacle limitation surfaces, and rescue and firefighting requirements that protect aircraft during approach and landing.

Two-element ICAO coding of an aerodrome, a code number based on reference field length and a code letter based on wingspan and outer main gear wheel span, used to relate aerodrome facilities to aircraft characteristics.

Imaginary surface extending outward and upward from a runway or aerodrome that defines the limits to which objects may project into airspace, protecting aircraft on approach and departure from collision hazards.

Airspace designation between flight levels 290 and 410 where approved aircraft may be separated vertically by 1,000 feet instead of 2,000 feet, increasing capacity and requiring specific altimetry and monitoring approval.

Ground-based or satellite system that measures the actual altitude-keeping performance of aircraft flying in RVSM airspace, used to verify that operators and aircraft types meet the required altimetry standards.

The difference between the altitude indicated by an aircraft's altimetry system and the true altitude, a key performance measure monitored for aircraft approved to operate in RVSM airspace.

A surface of constant atmospheric pressure related to a datum of 1013.25 hectopascals and expressed in hundreds of feet, used above the transition altitude so all aircraft share a common pressure reference.

The altitude above which an aircraft's altimeter is set to standard pressure and the aircraft flies by flight levels, ensuring vertical separation from aircraft below using local pressure settings.

The lowest flight level available for use above the transition altitude, often chosen to provide adequate vertical clearance between aircraft at that flight level and aircraft flying at the transition altitude.

A specified geographical location, defined by coordinates or by a navigation aid, used to define a route, a flight path, or an area navigation procedure for aircraft navigation.

A method of navigation that permits aircraft operation on any desired flight path within the coverage of ground or space-based navigation aids, or within the limits of self-contained onboard equipment.

A navigation specification stating the onboard performance monitoring and alerting required for operations along a defined path, with a specified accuracy, integrity, continuity, and availability standard.

ICAO framework that replaces sensor-specific navigation requirements with performance specifications, allowing aircraft to fly defined paths using RNAV and RNP specifications based on demonstrated navigation capability.

The distance from the nominal flight path within which an aircraft is expected to remain for 95 percent of the flight time, used in RNAV and RNP specifications to define obstacle clearance and route spacing.

Precision approach system using a localizer for lateral guidance and a glide path for vertical guidance, with marker beacons or distance measuring equipment providing range information to the runway.

The component of an instrument landing system that transmits a VHF signal along the extended runway centerline, giving pilots lateral guidance to align with the runway during an approach and landing.

The vertical guidance component of an instrument landing system, normally set at about three degrees above the horizontal, informing pilots of their position relative to the ideal descent path to the runway.

A specified altitude in a precision approach at which a missed approach must be initiated if the required visual reference to continue the approach has not been established.

A predefined sequence of maneuvers to be followed when an approach cannot be completed to a landing, designed to keep the aircraft clear of obstacles and return it to a safe altitude or holding fix.

The lowest altitude that provides a specified obstacle clearance, normally 1,000 feet, within a sector of 25 nautical miles around a navigation aid or waypoint, used during emergency or approach planning.

A published departure procedure that connects the runway environment to the en route structure, specifying track, altitude, and speed constraints to keep departing aircraft clear of obstacles and other traffic.

A published arrival procedure linking the en route structure to an instrument approach, providing track, altitude, and speed constraints that allow orderly descent and sequencing into busy terminal airspace.

Air traffic control separation applied between identified aircraft using surveillance-derived position information, with minimum distances set by the responsible authority and dependent on radar performance and display accuracy.

Air traffic control separation achieved without continuous surveillance, using position reports, time, altitude, and route geometry, and typically requiring larger minima than radar-based methods.

An authorization for an aircraft to proceed under specified conditions within controlled airspace, issued by air traffic control and required before flight in controlled airspace or under instrument flight rules.

A surveillance system that interrogates aircraft transponders, receiving coded replies that provide identification, pressure altitude, and, in modern systems, additional data used for air traffic control.

A surveillance technology in which aircraft automatically broadcast position, velocity, and identification derived from onboard systems, enabling ground and airborne users to receive traffic and surveillance information.

A data link application allowing text-based communication between air traffic controllers and pilots, supplementing or replacing voice radio for routine clearances and reducing readback errors.

A family of VHF digital communication protocols, notably VDL Mode 2, used to carry air-ground data such as CPDLC and ADS-C messages between aircraft and ground systems.

A ground-based navigation aid transmitting VHF signals that allow an aircraft to determine its magnetic bearing to or from the station, forming the basis of many conventional airway structures.

A radio navigation system that measures the slant range between an aircraft and a ground transponder by timing signal round trips, usually paired with VOR or ILS to provide a position fix.

A constellation of satellites providing worldwide position and time signals, used by aircraft for en route navigation, approaches, and performance-based navigation when augmented for integrity and accuracy.

A notice distributed by aeronautical information services containing information about temporary or permanent changes to facilities, services, or hazards that is essential to flight operations personnel.

A document published by a state containing aeronautical information of a lasting nature that is essential to air navigation, structured in general, en route, and aerodrome sections.

A notice containing explanatory or advisory information that does not qualify for a NOTAM or AIP amendment, covering subjects such as safety, navigation, or regulatory matters of interest to aviation.

The combined set of aeronautical documents maintained by a state, including the AIP, AIP supplements, NOTAMs, and circulars, providing a single reference framework for flight planning.

A systematic approach to managing safety in an organization, including policy, risk management, assurance, and promotion components, required of service providers to identify and control hazards.

An organizational environment in which individuals are encouraged to report errors and hazards without fear of punishment, while reckless or intentionally unsafe behavior remains subject to appropriate accountability.

A framework in which flight crews identify external threats, manage errors that arise, and avoid undesired aircraft states, integrating human performance considerations into everyday operational decision-making.

An accident in which an airworthy aircraft, under pilot control, is flown unintentionally into terrain, water, or obstacles, often prevented by terrain awareness systems and disciplined approach procedures.

A concise statement of the expected meteorological conditions at an aerodrome during a specified period, used for flight planning and approach decision-making alongside current observations.

A routine coded observation of surface weather at an aerodrome, reporting wind, visibility, runway visual range, weather phenomena, cloud, temperature, and pressure for operational use.

The range over which a pilot on the runway centerline can see runway markings or lights, reported in meters and used to determine minima for low-visibility takeoff and landing operations.

A forecast chart depicting hazardous en route weather such as thunderstorms, turbulence, icing, and jet streams, used by flight crews to plan routes and fuel and to anticipate in-flight conditions.

The boundary between the troposphere and stratosphere where temperature normally stops decreasing with height, marking the top of most weather and influencing cruise altitude selection and turbulence.