2 DEFINITIONS

2.1 List of Definitions
- 2.1.1 The definitions listed below are used in AIS publications:
  - Accelerate stop distance available (ASDA): Accelerate stop distance available for an abandoned take-off. ASDA is the declared length of the runway available, plus the length of the stopway (if provided).
  - Aerobatic flight: Any intentional manoeuvre in which the aircraft is in sustained inverted flight or is rolled from upright to inverted or from inverted to upright position, or manoeuvres such as rolls, loops, spins, upward vertical flight culminating in a stall turn, hammerhead or whip stall, or a combination of such manoeuvres.
  - Aerodrome: Any defined area of land or water intended or designed to be used either wholly or partially for the landing, departure, surface movement, and servicing of aircraft. This includes any buildings, installations and equipment on or adjacent to the area used in connection with the aerodrome or its administration.
  - Aerodrome elevation: The elevation of the highest point of the landing area.
  - Aerodrome ground services: Services provided at an aerodrome, including Aeronautical Information Service pre-flight briefing, Air Traffic Services (aerodrome control, aerodrome flight information service, alerting service), Rescue Fire Service, Aviation Security Service, and MET service.
  - Aerodrome reference point: The designated geographical location of an aerodrome.
  - Aerodrome traffic circuit: The specified path to be flown by aircraft operating in the vicinity of an aerodrome.
  - Aeronautical fixed telecommunication network (AFTN): A worldwide system of aeronautical fixed circuits provided, as part of the aeronautical fixed service, for the exchange of messages and/or digital data between aeronautical fixed stations.
  - Aircraft operating agency: The person, organisation or enterprise engaged in, or offering to engage in, an aircraft operation.
  - Air taxiing: Movement of a helicopter/VTOL above the surface of an aerodrome, normally in ground effect and at a ground speed normally less than 37 km/h (20 kt). Note: The actual height may vary, and some helicopters may require air-taxiing above 8 m (25 ft) AGL to reduce ground effect turbulence or provide clearance for cargo sling loads.
  - Air traffic control (ATC): A service provided for the purpose of preventing collisions between aircraft, preventing collisions on the manoeuvring area between aircraft and obstructions, and expediting and maintaining a safe and efficient flow of air traffic.
  - Air traffic services (ATS): A set of services including air traffic control, flight information service, aerodrome flight information service (AFIS), alerting service, and any other service considered by the Director to be necessary or desirable for the safe and efficient operation of the civil aviation system.
  - Alerting service: A service provided to notify appropriate organisations regarding aircraft in need of search and rescue aid, and assistance for such organisations as required.
  - An alerting service is provided to aircraft that:
    - (a) are provided with an air traffic control service; or
    - (b) file a flight plan; or
    - (c) submit a SARWATCH; or
    - (d) are known by any air traffic service to be in need of assistance (includes unlawful interference).
  - Altitude: The vertical distance of a level, a point or an object considered as a point, measured from mean sea level (MSL).
  - Apron: A defined area on a land aerodrome intended to accommodate aircraft for purposes of loading or unloading passengers or cargo, refuelling, parking, or maintenance.
  - Area minimum altitude (AMA): The minimum altitude to be used under instrument meteorological conditions (IMC), that provides a minimum obstacle clearance within a specified area, normally formed by parallels and meridians. Note: The minimum vertical clearance is 300 m (1000 ft) or in designated mountainous terrain 600 m (2000 ft) above all obstacles located in the area specified, rounded up to the nearest (next higher) 30 m (100 ft).
  - Area navigation (RNAV): A method of navigation which permits aircraft operation on any desired flight path within the coverage of ground- or space-based 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 operations that do not meet the definition of performance-based navigation.
  - 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 MLAT.
  - Automatic dependent surveillance -- broadcast (ADS-B): A means by which aircraft, aerodrome vehicles and other objects can automatically transmit and/or receive data such as identification, position and additional data, as appropriate, in a broadcast mode via a data link.
  - Automatic dependent surveillance -- contract (ADS-C): A means by which the terms of an ADS-C agreement will be exchanged between the ground system and the aircraft, via a data link, specifying under what conditions ADS-C reports would be initiated, and what data would be contained in the reports. Note: The abbreviated term "ADS contract" is commonly used to refer to ADS event contract, ADS demand contract, ADS periodic contract or an emergency mode.
  - Automatic terminal information service (ATIS): The automatic provision of current, routine information to arriving and departing aircraft throughout 24 hours or a specified portion thereof:
    - (a) Data link-automatic terminal information service (D-ATIS). The provision of ATIS via data link.
    - (b) Voice -- automatic terminal information service (Voice-ATIS). The provision of ATIS by means of continuous and repetitive voice broadcasts.
  - Barometric vertical navigation (baro-VNAV): A navigation system that presents to the pilot computed vertical guidance referenced to a specified vertical path angle (VPA), nominally 3°. The computer-resolved vertical guidance is based on barometric altitude and is specified as a vertical path angle from RDH.
  - Baro-VNAV approach procedures utilise a DA/H and not an MDA/H, and neither a FAF nor a missed approach point (MAPt) is identified, instead they utilise a final approach point (FAP) only. They use obstacle assessment surfaces similar to those for ILS, but based on the specific RNAV lateral guidance system.
  - Ceiling: The height above the ground or water of the base of the lowest layer of cloud below 20,000 ft covering more than half the sky.
  - Change-over point (COP): The point at which an aircraft navigating on an ATS route segment defined by reference to very high frequency omnidirectional radio ranges is expected to transfer its primary navigational reference from the facility behind the aircraft to the next facility ahead of the aircraft. Note: Change-over points are established to provide the optimum balance in respect of signal strength and quality between facilities at all levels to be used and to ensure a common source of azimuth guidance for all aircraft operating along the same portion of a route segment.
  - Controlled aerodrome: An aerodrome at which air traffic control service is provided to aerodrome traffic. Note: The term controlled aerodrome indicates that air traffic control service is provided to aerodrome traffic but does not necessarily imply that a control zone exists.
  - Controlled airspace: An airspace of defined dimensions within which an air traffic control service is provided to IFR flights, and to VFR flights, in accordance with the airspace classification.
  - Controlled flight: Any flight that is provided with an air traffic control service.
  - Controllerpilot data link communications (CPDLC): A means of communication between controller and pilot, using data link for ATC communications.
  - Day means the hours between:
    - (a) the beginning of morning civil twilight, which is when the centre of the rising sun's disc is 6 degrees below the horizon; and
    - (b) the end of evening civil twilight, which is when the centre of the setting sun's disc is 6 degrees below the horizon.
  - Decision Altitude (DA) or Decision Height (DH): A specified altitude or height in the precision approach, or approach with vertical guidance, at which a missed approach must be initiated if the required visual reference to continue the approach has not been established. DA is referenced to mean sea level, and DH is referenced to the threshold elevation.
  - Domestic: A term pertaining to either an aerodrome which is not a designated international aerodrome, airspace, Air Traffic Services, or flight operations contained wholly within the New Zealand Flight Information Region and between New Zealand and the Chatham Islands.
  - Elevation: The vertical distance of a point or a level, on or affixed to the surface of the earth, measured from mean sea level.
  - Estimated off-block time (EOBT): The estimated time at which the aircraft will commence movement associated with departure. Note: The EOBT is the estimated time at which the aircraft will commence movement associated with departure and is specified in field 13 of the ICAO flight plan. Airlines consider this time to be doors closed, or parking brake off, or disconnection from the air-bridge.
  - Estimated time of arrival (ETA):
    - For IFR flights, the time at which it is estimated that the aircraft will arrive over that designated point, defined by reference to navigation aids, from which it is intended that an instrument approach procedure will be commenced, or if no navigation aid is associated with the aerodrome, the time at which the aircraft will arrive over the aerodrome.
    - For VFR flights, the time at which it is estimated that the aircraft will arrive over the aerodrome.
  - Estimated time of departure (ETD): The estimated time at which the aircraft will commence take-off.
  - Estimated time over (ETO): The estimated time over a significant point. Flight information service: A service provided for the purpose of giving advice and information useful for the safe and efficient conduct of flights.
  - Flight level: A surface of constant atmospheric pressure which is related to a specific pressure datum 1013.2 hectopascals (hPa) and is separated from other such surfaces by specific pressure intervals.
    - Note 1: A pressure type altimeter calibrated in accordance with the Standard Atmosphere:
      - (a) when set to a QNH altimeter setting, will indicate altitude; and
      - (b) when set to a pressure of 1013.2 hPa may be used to indicate flight levels.
    - Note 2: The terms "height" and "altitude" used above indicate altimetric rather than geometric heights and altitudes.
  - Height: The vertical distance of a level, a point or an object considered as a point, measured from a specified datum.
  - Heliport: Any defined area of land or water, and any defined area on a structure, intended or designed to be used either wholly or partly for the landing, departure, and surface movement of helicopters.
  - International Civil Aviation Organization (ICAO): The United Nations specialised agency established under the Convention on International Civil Aviation (Chicago Convention). New Zealand is a signatory to the Convention. Standards and Recommended Practices (SARPs) contained in the Annexes to the Convention form the basis for the New Zealand aviation regulatory regime.
  - Landing area: That part of a movement area intended for the landing or take-off of aircraft.
  - Level: A generic term relating to the vertical position of an aircraft in flight and meaning variously height, altitude or flight level.
  - Manoeuvring area: That part of an aerodrome to be used for the take-off and landing of aircraft, and for the surface movement of aircraft associated with take-off and landing, but does not include areas set aside for loading, unloading, or maintenance of aircraft.
  - Minimum descent altitude (MDA) or Minimum descent height (MDH): A specified altitude or height in a non-precision approach or circling approach below which descent must not be made without the required visual reference. MDA is referenced to mean sea level and MDH is referenced to the aerodrome elevation or to the threshold elevation if that is more than 7 ft below the aerodrome elevation. MDH for a circling approach is referenced to the aerodrome elevation.
  - Minimum enroute altitude (MEA): MEA is the lowest altitude at which adequate NDB signal can be received on an NDB route. Minimum flight altitude (MFA): The lowest level at or above the route sector minimum safe altitude/MRA/MEA or upper limit of Volcanic Hazard Zone or Danger/Restricted Area, as appropriate, in accordance with the direction of flight as prescribed in CAR 91.425.
  - Minimum fuel: The term used to describe a situation in which an aircraft's fuel supply has reached a state where the flight is committed to land at a specific aerodrome and no additional delay can be accepted.
  - Minimum reception altitude (MRA): MRA is the lowest altitude at which adequate VOR signal can be received on a VOR route.
  - Minimum safe altitude: The lowest altitude, rounded up to the nearest 100 ft, which provides the terrain clearance required by CAR 91.423. Note that this is not the ICAO MSA (minimum SECTOR altitude) which in New Zealand is referred to as MSA 25 NM -- see below.
  - Minimum sector altitude (MSA 25 NM): The lowest altitude that may be used that will provide a minimum clearance of 1000 ft (2000 ft in designated mountainous zones) above all objects located in an area contained within a sector of a circle of 25 NM radius centred on a radio navigation aid or, where associated with GNSS procedures, the Aerodrome Reference Point.
  - Movement area: That part of an aerodrome area to be used for the take-off, landing and taxiing of aircraft, consisting of the manoeuvring area and apron(s).
  - Multilateration (MLAT) system: A group of equipment configured to provide position derived from the secondary surveillance radar (SSR) transponder signals (replies or squitters) primarily using time difference of arrival (TDOA) techniques. Additional information, including identification, can be extracted from the received signals.
  - Navigation specification: A set of aircraft and flight crew requirements needed to support performance-based navigation operations within a defined airspace. There are two kinds of navigation specifications:
    - (a) Required navigation performance (RNP) specification. A navigation specification based on area navigation that includes the requirement for performance monitoring and alerting, designated by the prefix RNP, e.g. RNP 4, RNP APCH.
    - (b) Area navigation (RNAV) specification. A navigation specification based on area navigation that does not include the requirement for performance monitoring and alerting, designated by the prefix RNAV, e.g. RNAV 5, RNAV 1.
  - Night means the hours between:
    - (a) the end of evening civil twilight, which is when the centre of the setting sun's disc is 6 degrees below the horizon; and
    - (b) the beginning of morning civil twilight, which is when the centre of the rising sun's disc is 6 degrees below the horizon.
  - NOTAM: A notice containing information concerning the establishment, condition or change in any aeronautical facility, service, procedure or hazard, the timely knowledge of which is essential to personnel concerned with flight operations. NOTAM are distributed by means of telecommunications.
  - Performance-based navigation (PBN): 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 expressed in navigation specifications (RNAV specification, RNP specification) in terms of accuracy, integrity, continuity, availability and functionality needed for the proposed operation in the context of a particular airspace concept.
  - Procedure Altitude: A recommended altitude established to accommodate a stabilised descent profile on a prescribed descent angle in the final approach segment. Procedure altitudes may also be applied in the intermediate segment. A procedure altitude will never be less than the segment obstacle clearance altitude.
  - Radar: A radio detection device which provides information on range, azimuth and/or elevation of objects. Note -- The term "radar service" may be interpreted as an "ATS surveillance service" provided by PSR, SSR, MLAT or ADS-B systems if such service is provided.
  - Rated coverage: The rated coverage of an NDB is the area surrounding the NDB within which bearings can be obtained with an accuracy sufficient for the nature of the operation concerned. The area is defined by a radial distance from the NDB. This is similar to the ICAO term "effective coverage".
  - Remote pilot: The person who manipulates the flight controls of a remotely-piloted aircraft during flight time.
  - Remote pilot station: The station at which the remote pilot manages the flight of an unmanned aircraft.
  - Remotely-piloted aircraft: An aircraft where the flying pilot is not on board the aircraft. Note -- this is a subcategory of unmanned aircraft. Remotely-piloted aircraft system: A set of configurable elements consisting of a remotely-piloted aircraft, its associated remote pilot station(s), the required command and control links and any other system elements as may be required, at any point during flight operation.
  - RPA observer: A remote crew member who, by visual observation of the remotely-piloted aircraft, assists the remote pilot in the safe conduct of the flight.
  - Runway end identifier lights (REIL): Comprise very high intensity uni-directional light projectors located on either side of the runway centreline, on or outside of the line of the runway edge lights, and at or downwind of the landing threshold. The lights are aligned to be visible from the approach direction and are syncronised to flash simultaneously brilliant white at a minimum rate of 60 flashes per minute.
  - Runway end safety area: A cleared and graded area off the end of the runway strip intended to minimise damage to aircraft in the event of the aircraft undershooting or overrunning the runway.
  - SARTIME: The time nominated by a pilot for the initiation of alerting action.
  - Segment OCA: An altitude that provides required obstacle clearance for a given segment of the approach. It is a minimum altitude established by the procedure designer and is meant to be a "do not descend below" altitude.
  - Simultaneous operations -- instrument conditions: RESERVED (not currently applicable at New Zealand aerodromes).
  - Simultaneous operations -- visual conditions: Operations using parallel runways where both may be in use at the time, in accordance with the following criteria (excluding provision for wake turbulence separation requirements):
    - (a) Uncontrolled aerodrome -- simultaneous-independent operations, with displacement between parallel runway centrelines not less than 210 m.
    - (b) Controlled aerodrome -- aerodrome control service on watch:
      - (i) simultaneous-independent operations: where ATC controls aircraft with displacement between parallel runway centrelines not less than 210 m (not less than 165 m edge-to-edge if grass runways); or
      - (ii) simultaneous-dependent operations: where ATC controls aircraft including sequencing or staggering operations (to avoid side-by-side parallel flight or side-by-side manoeuvring on a parallel runway); or
      - (iii) simultaneous-segregated operations: where ATC controls aircraft departures on one runway and aircraft arrivals on the parallel runway.
  - Taxi: Movement of an aircraft on the surface of an aerodrome or on water, excluding take-off and landing, but including, in the case of helicopters, operation over the surface of an aerodrome within a height band associated with ground effect and at speeds associated with air-taxiing.
  - Terminal control area (TMA): A control area normally established at the confluence of ATS routes in the vicinity of one or more major aerodromes.
  - Transition altitude: The altitude at or below which the vertical position of an aircraft is controlled by reference to altitudes.
  - Transition level: The lowest flight level available for use above the transition altitude. May also be known as the Lowest Usable Flight Level. The transition level is FL150, except that:
    - (a) when the zone area QNH is 980 hPa or less, FL160 is to be used; or
    - (b) within the area of a circle of 20 NM radius centred on Mt Cook, FL160 is to be used if the aircraft is in IMC.
  - Transition layer: The airspace between the transition altitude and the transition level.
  - Vicinity of an aerodrome: An area around an aerodrome where aircraft carry out manoeuvres associated with entering, leaving, or operating within an aerodrome traffic circuit.
  - Visual departure: A departure by an IFR flight when either part or all of an instrument departure procedure is not completed and the departure is executed in visual reference to terrain.
  - Visual meteorological conditions (VMC): Meteorological conditions expressed in terms of visibility, distance from cloud, and ceiling equal to or better than specified minima.
  - VMC varies according to the type of airspace, and is equivalent to the MET requirements for VFR flight in that class of airspace (Refer ENR 1.2 Visual Flight Rules).
  - Visual reference: Continuous reference to terrain (land or water).
  - Visual segment surface: Applicable to straight-in instrument approach procedures only -- a surface 1.12° below the promulgated approach angle protecting the visual component of the approach from the point where OCH is reached to the threshold.