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Abbreviation for: North American Datum 1983

Fr: NAD83


Abbreviation for: North American Route


NAR System

Abbreviation for: North American Routes System

Fr: réseau NAR


U.S.: Abbreviation for: National Airspace System


Abbreviation for: North Atlantic



Abbreviation for: North Atlantic organized track system


National Airspace System

U.S.: The common network of U.S. airspace; air navigation facilities, equipment and services, airports or landing areas; aeronautical charts, information and services; rules, regulations and procedures, technical information, and manpower and material. Included are system components shared jointly with the military.

  • abbreviation: NAS
NAT Region

The region encompassing the northern portion of the Atlantic Ocean, as defined by ICAO.

Fr: Région NAT


Abbreviation for: navigation aid



The corporation providing air navigation services in Canadian airspace and ATS in international airspace for which Canada has assumed responsibility.


navigation aid

Any visual or electronic device, airborne or on the surface of the earth, that provides point-to-point guidance information or position data to aircraft in flight.

  • abbreviation: NAVAID
  • also called: navigational aid

Fr: aide à la navigation

navigational aid

Other expression for: navigation aid (NAVAID)

navigation change-over point

Other expression for: change-over point

A set of aircraft and flight crew requirements needed to support performance-based navigation operations within a defined airspace. There are two types of navigation specification: RNAV specification and RNP specification.

Fr: spécification de navigation


Abbreviation for: Northern Control Area



Abbreviation for: Northern Domestic Airspace



Abbreviation for: non-directional beacon



An expression used in radiocommunication meaning “No,” “Permission not granted,” or “That is not correct.”

Fr: « Négatif »


The period of time during any day that starts at the end of evening civil twilight and ends at the start of morning civil twilight.

Fr: nuit

no-compass approach

A radar approach or vector provided to a pilot when the compass or directional indicator is malfunctioning. Instead of providing the pilot with headings to be flown, the controller observes the radar track and issues the control instructions “Turn right,” “Turn left,” or “Stop turn,” as appropriate.

Fr: approche radar sans compas

no gyro approach

U.S.: Expression for: no-compass approach

noise abatement procedure

A procedure developed to ensure that the necessary safety of flight operations is maintained while exposure to noise on the ground is minimized.

Fr: procédure d’atténuation du bruit

non-ATS OI

Abbreviation for: non-ATS operating irregularity

Fr: IE non ATS

non-ATS operating irregularity

A situation that occurs when ATS are being provided and when a preliminary investigation indicates that a hazardous situation or loss of separation may have occurred and that ATS have not contributed to the situation.

  • abbreviation: non-ATS OI

Fr: irrégularité d’exploitation non ATS

non-directional beacon

An LF/MF or UHF radio beacon transmitting non-directional signals whereby the pilot of an aircraft equipped with direction-finding equipment can determine his or her bearing to or from the radio beacon and “home” on or track to or from the station. When the radio beacon is installed in conjunction with the instrument landing system (ILS) marker, it is normally called a marker beacon.

Fr: radiophare non directionnel

non-instrument runway

A runway intended for the operation of aircraft using visual approach procedures, or an instrument approach down to a height above aerodrome (HAA) or a height above touchdown zone elevation (HAT) not lower than 500 ft.

Fr: piste à vue

non-precision approach procedure

An instrument approach procedure (IAP) in which only electronic azimuth information is provided. No electronic glide path (GP) information is provided and obstacle assessment in the final segment is based on minimum descent altitude (MDA).

Fr: procédure d’approche de non-précision

non-precision runway

A runway served by visual aids and non-visual NAVAIDs that provide at least lateral guidance adequate for approach down to a height above aerodrome (HAA)/height above touchdown (HAT) of 500 ft but not lower than 250 ft.

Fr: piste de non-précision

non-radar route

A route on which an aircraft is able to determine its position, track and, consequently, the minimum IFR altitude without the benefit of radar information.

Fr: route non radar

non-radar separation

The separation used when aircraft position information is derived from sources other than radar.

Fr: espacement non radar

non-RVSM aircraft

An aircraft that does not meet reduced vertical separation minimum (RVSM) requirements for certification and/or for operator approval.

Fr: aéronef non RVSM

non-standard formation

A formation flight for which, through prior arrangement with ATC, the flight leader has received approval for formation dimensions other than standard ones.

Fr: formation non standard

no radio

An expression describing an inability to communicate by radio owing to the absence or failure of radio equipment.

  • abbreviation: NORDO

Fr: sans radio


Abbreviation for: no radio


normal operating zone

An airspace of defined dimensions, extending to either side of an instrument landing system (ILS) localizer centreline. Only the inner half of the normal operating zone is taken into account in independent approaches.

  • abbreviation: NOZ

Fr: zone d’évolution normale

North American Datum 1983

The geodetic coordinate reference system used in Canada and the U.S. that allows the user to mathematically describe (in degrees of latitude and longitude) any position on the earth’s surface. NAD83 uses North American ground stations as references.

Note: In Canada, NAD83 has been deemed to be equivalent to World Geodetic System 1984 for aviation purposes.

Fr: Système de référence nord-américain de 1983

North American Route

Other expression for: North American Routes System (NAR System)

  • abbreviation: NAR
North American Routes System

A special routing system consisting of routes located within the high level airspace established to facilitate control of the flow of international air traffic between the North Atlantic (NAT) and domestic airspace, as described in the “Planning” section of the Canada Flight Supplement (CFS).

  • abbreviation: NAR System
  • also called: North American Route (NAR)

Fr: réseau de routes aériennes nord-américaines

North Atlantic organized track system

A variable track structure developed daily by appropriate Oceanic Area Control Centres (Gander [West] or Shanwick [East]) to create a series of minimum time tracks across the North Atlantic (NAT) taking into consideration weather, opposite direction traffic, danger areas, airspace reservations, usable NAVAIDs, aircraft volume and domestic routes.

  • abbreviation: NAT OTS

Fr: système de routes organisées de l’Atlantique Nord

Northern Control Area

A controlled airspace within the Northern Domestic Airspace (NDA) at FL 230 and above.

  • abbreviation: NCA

Fr: région de contrôle du Nord

Northern Domestic Airspace

As geographically delineated in the Designated Airspace Handbook (DAH), a subdivision of Canadian Domestic Airspace (CDA) commencing at the North Pole and extending southward to the northern limit of the Southern Domestic Airspace (SDA).

  • abbreviation: NDA

Fr: espace aérien intérieur du Nord

North Warning System

A system that provides airspace surveillance and command and control capability for air defence identification over the northern approaches to the continent. It consists of 15 long-range radars (LRR) and 39 short-range radars (SRR) across the Canadian Arctic and Alaska. Systems deployed on Canadian territory are operated and maintained by Canada for the North American Aerospace Defence Command (NORAD) on behalf of Canada and the United States.

  • abbreviation: NWS

Fr: Système d’alerte du Nord


A notice distributed by means of telecommunication 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.



Other expression for: RSC/CRFI NOTAM

notice to airmen

U.S.: Expression for: NOTAM

no-transgression zone

A corridor of airspace of defined dimensions, located centrally between the two extended runway centrelines, where controller intervention is required to manoeuvre the non-blundering aircraft when the airspace is penetrated by an aircraft conducting a simultaneous approach to the adjacent parallel or near-parallel instrument runway.

  • abbreviation: NTZ

Fr: zone de non-transgression

“. . . now”

An expression used by ATS when prompt compliance with an instruction is required.

Fr: « ... maintenant »


Abbreviation for: normal operating zone



Abbreviation for: no-transgression zone



Abbreviation for: North Warning System

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