Aeronautical Terms beginning with N
National Airspace System
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.
National Flight Data Center
A facility in Washington D.C., established by FAA to operate a central aeronautical information service for the collection, validation, and dissemination of aeronautical data in support of the activities of government, industry, and the aviation community. The information is published in the National Flight Data Digest.
National Flight Data Digest
A daily (except weekends and Federal holidays) publication of flight information appropriate to aeronautical charts, aeronautical publications, Notices to Airmen, or other media serving the purpose of providing operational flight data essential to safe and efficient aircraft operations.
Navaid Classes
VOR, VORTAC, and TACAN aids are classed according to their operational use. The three classes of NAVAIDs are: a. T-Terminal. b. L-Low altitude. c. H-High altitude. Note: The normal service range for T, L, and H class aids is found in the AIM. Certain operational requirements make it necessary to use some of these aids at greater service ranges than specified. Extended range is made possible through flight inspection determinations. Some aids also have lesser service range due to location, terrain, frequency protection, etc. Restrictions to service range are listed in Airport/Facility Directory.
Navigable Airspace
Airspace at and above the minimum flight altitudes prescribed in the CFRs including airspace needed for safe takeoff and landing.
Navigation Reference System (NRS)
The NRS is a system of waypoints developed for use within the United States for flight planning and navigation without reference to ground based navigational aids. The NRS waypoints are located in a grid pattern along defined latitude and longitude lines. The initial use of the NRS will be in the high altitude environment in conjunction with the High Altitude Redesign initiative. The NRS waypoints are intended for use by aircraft capable of point-to-point navigation.
Navigation Specification [ICAO]
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: RNP and RNAV. Note: The Performance-based Navigation Manual (Doc 9613), Volume II contains detailed guidance on navigation specifications.
Navigational Aid
Any visual or electronic device airborne or on the surface which provides point-to-point guidance information or position data to aircraft in flight.
Negative
“No,” or “permission not granted,” or “that is not correct.”
Negative Contact
Used by pilots to inform ATC that: a. Previously issued traffic is not in sight. It may be followed by the pilot’s request for the controller to provide assistance in avoiding the traffic. b. They were unable to contact ATC on a particular frequency.
Night
The time between the end of evening civil twilight and the beginning of morning civil twilight, as published in the American Air Almanac, converted to local time.
Night [ICAO]
The hours between the end of evening civil twilight and the beginning of morning civil twilight or such other period between sunset and sunrise as may be specified by the appropriate authority. Note: Civil twilight ends in the evening when the center of the sun’s disk is 6 degrees below the horizon and begins in the morning when the center of the sun’s disk is 6 degrees below the horizon.
No Gyro Approach
A radar approach/vector provided in case of a malfunctioning gyro-compass or directional gyro. Instead of providing the pilot with headings to be flown, the controller observes the radar track and issues control instructions “turn right/left” or “stop turn” as appropriate.
No Gyro Vector
No Gyro Approach. A radar approach/vector provided in case of a malfunctioning gyro-compass or directional gyro. Instead of providing the pilot with headings to be flown, the controller observes the radar track and issues control instructions “turn right/left” or “stop turn” as appropriate.
No Transgression Zone (NTZ)
The NTZ is a 2,000 foot wide zone, located equidistant between parallel runway final approach courses in which flight is not allowed.
Nonapproach Control Tower
Authorizes aircraft to land or takeoff at the airport controlled by the tower or to transit the Class D airspace. The primary function of a nonapproach control tower is the sequencing of aircraft in the traffic pattern and on the landing area. Nonapproach control towers also separate aircraft operating under instrument flight rules clearances from approach controls and centers. They provide ground control services to aircraft, vehicles, personnel, and equipment on the airport movement area.
Nondirectional Beacon
An L/MF or UHF radio beacon transmitting nondirectional 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. When the radio beacon is installed in conjunction with the Instrument Landing System marker, it is normally called a Compass Locator.
Nonmovement Areas
Taxiways and apron (ramp) areas not under the control of air traffic.
Nonprecision Approach
Nonprecision Approach Procedure.
Nonprecision Approach Procedure
A standard instrument approach procedure in which no electronic glideslope is provided; e.g., VOR, TACAN, NDB, LOC, ASR, LDA, or SDF approaches.
Nonprecision Approach Runway
An instrument runway served by visual aids and a nonvisual aid providing at least directional guidance adequate for a straight-in approach.
Nonradar
Precedes other terms and generally means without the use of radar, such as: Nonradar Approach, Nonradar Approach Control, Nonradar Arrival, Nonradar Route, and Nonradar Separation.
Nonradar Approach
Used to describe instrument approaches for which course guidance on final approach is not provided by ground-based precision or surveillance radar. Radar vectors to the final approach course may or may not be provided by ATC. Examples of nonradar approaches are VOR, NDB, TACAN, and ILS/MLS approaches.
Nonradar Approach Control
An ATC facility providing approach control service without the use of radar.
Nonradar Arrival
An aircraft arriving at an airport without radar service or at an airport served by a radar facility and radar contact has not been established or has been terminated due to a lack of radar service to the airport.
Nonradar Route
A flight path or route over which the pilot is performing his/her own navigation. The pilot may be receiving radar separation, radar monitoring, or other ATC services while on a nonradar route.
Nonradar Separation
The spacing of aircraft in accordance with established minima without the use of radar; e.g., vertical, lateral, or longitudinal separation.
Nonradar Separation [ICAO]
The separation used when aircraft position information is derived from sources other than radar.
Normal Operating Zone (NOZ)
The NOZ is the operating zone within which aircraft flight remains during normal independent simultaneous parallel ILS approaches.
Notice To Airmen
A notice containing information (not known sufficiently in advance to publicize by other means) concerning the establishment, condition, or change in any component (facility, service, or procedure of, or hazard in the National Airspace System) the timely knowledge of which is essential to personnel concerned with flight operations. There are two types: NOTAM(D) and FDC NOTAM.
Notices To Airmen Publication
A publication issued every 28 days, designed primarily for the pilot, which contains current NOTAM information considered essential to the safety of flight as well as supplemental data to other aeronautical publications. The contraction NTAP is used in NOTAM text.
Numerous Targets Vicinity (Location)
A traffic advisory issued by ATC to advise pilots that targets on the radar scope are too numerous to issue individually.
Copyright © 2002-2026 Touring Machine Company. All Rights Reserved.