NAS-

(See NATIONAL AIRSPACE SYSTEM.)

NAT HLA–

(See NORTH ATLANTIC HIGH LEVEL AIRSPACE.)

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 BEACON CODE ALLOCATION PLAN AIRSPACE (NBCAP)- Airspace over United States ­territory located within the North American continent between Canada and Mexico, including adjacent territorial ­waters outward to about boundaries of oceanic control areas (CTA)/Flight Information Regions (FIR).

(See FLIGHT INFORMATION REGION.)

NATIONAL FLIGHT DATA DIGEST (NFDD)- 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.

NATIONAL SEARCH AND RESCUE PLAN- An interagency agreement which provides for the effective ­utilization of all available facilities in all types of search and rescue missions.

NATIONAL SECURITY AREA (NSA)–

(See SPECIAL USE AIRSPACE.)

NAVAID-

(See NAVIGATIONAL AID.)

NAVAID CLASSES- VOR, VORTAC, and TACAN aids are classed according to their operational use. The ­three classes of NAVAIDs are:

1. T- Terminal.
2. L- Low altitude.
3. H- High altitude.

   NAVIGABLE AIRSPACE- Airspace at and above the minimum flight altitudes prescribed in the CFRs ­including airspace needed for safe takeoff and landing.

   (Refer to 14CFR part91.)

   NAVIGATION REFERENCE SYSTEM (NRS)- The NRS is a system of waypoints for use within the United ­States for flight planning and navigation without reference to ground based navigational aids. These waypoints ­are located in a grid pattern along defined latitude and longitude lines and are available for use at or above FL180 ­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:

4. 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.
5. 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.

   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.

   (See AIR NAVIGATION FACILITY.)

   NAVSPEC-

   (See NAVIGATION SPECIFICATION [ICAO].)

   NBCAP AIRSPACE-

   (See NATIONAL BEACON CODE ALLOCATION PLAN AIRSPACE.)

   NDB-

   (See NONDIRECTIONAL BEACON.)

   NEGATIVE- “No,” or “permission not granted,” or “that is not correct.”

   NEGATIVE CONTACT- Used by pilots to inform ATC that:

6. 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.
7. They were unable to contact ATC on a particular frequency.

   NFDD-

   (See NATIONAL FLIGHT DATA DIGEST.)

   NIGHT- The time between the end of evening civil twilight and the beginning of morning civil twilight, as ­published in the Air Almanac, converted to local time.

   (See ICAO term NIGHT.)

   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.

   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.

   (Refer to AIM.)

   NO GYRO VECTOR-

   (See NO GYRO APPROACH.)

   NO TRANSGRESSION ZONE (NTZ)- The NTZ is a 2,000 foot wide zone, located equidistant between ­parallel runway or SOIA final approach courses, in which flight is normally not allowed.

   NONAPPROACH CONTROL TOWER- Author‐izes 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.

   NONCOMMON ROUTE/PORTION- That segment of a North American Route between the inland navigation ­facility and a designated North American terminal.

   NON-COOPERATIVE SURVEILLANCE- Any surveillance system, such as primary radar, that is not ­dependent upon the presence of any equipment on the aircraft or vehicle to be tracked.

   (See COOPERATIVE SURVEILLANCE.)

   (See RADAR.)

   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.

   (See AUTOMATIC DIRECTION FINDER.)

   (See COMPASS LOCATOR.)

   NONMOVEMENT AREAS- Taxiways and apron (ramp) areas not under the control of air traffic.

   NONPRECISION APPROACH-

   (See 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.

   NONRADAR- Precedes other terms and generally means without the use of radar, such as:

8. 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, ILS, RNAV, and ­GLS approaches.

   (See FINAL APPROACH COURSE.)

   (See FINAL APPROACH‐IFR.)

   (See INSTRUMENT APPROACH PROCEDURE.)

   (See RADAR APPROACH.)

9. Nonradar Approach Control. An ATC facility providing approach control service without the use of radar.

   (See APPROACH CONTROL FACILITY.)

   (See APPROACH CONTROL SERVICE.)

10. 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.

    (See RADAR ARRIVAL.)

    (See RADAR SERVICE.)

11. 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.

    (See RADAR ROUTE.)

12. Nonradar Separation. The spacing of aircraft in accordance with established minima without the use of ­radar; e.g., vertical, lateral, or longitudinal separation.

    (See RADAR SEPARATION.)

    NON-RESTRICTIVE ROUTING (NRR)- Portions of a proposed route of flight where a user can flight plan ­the most advantageous flight path with no requirement to make reference to ground-based NAVAIDs.

    NOPAC-

    (See NORTH PACIFIC.)

    NORDO (No Radio)- Aircraft that cannot or do not communicate by radio when radio communication is ­required are referred to as “NORDO.”

    (See LOST COMMUNICATIONS.)

    NORMAL OPERATING ZONE (NOZ)- The NOZ is the operating zone within which aircraft flight remains ­during normal independent simultaneous parallel ILS approaches.

    NORTH AMERICAN ROUTE- A numerically coded route preplanned over existing airway and route systems ­to and from specific coastal fixes serving the North Atlantic. North American Routes consist of the following:

13. Common Route/Portion. That segment of a North American Route between the inland navigation facility ­and the coastal fix.
14. Noncommon Route/Portion. That segment of a North American Route between the inland navigation ­facility and a designated North American terminal.
15. Inland Navigation Facility. A navigation aid on a North American Route at which the common route and/or ­the noncommon route begins or ends.
16. Coastal Fix. A navigation aid or intersection where an aircraft transitions between the domestic route ­structure and the oceanic route structure.

    NORTH AMERICAN ROUTE PROGRAM (NRP)- The NRP is a set of rules and procedures which are ­designed to increase the flexibility of user flight planning within published guidelines.

    NORTH ATLANTIC HIGH LEVEL AIRSPACE (NAT HLA)- That volume of airspace (as defined in ICAO ­Document 7030) between FL 285 and FL 420 within the Oceanic Control Areas of Bodo Oceanic, Gander ­Oceanic, New York Oceanic East, Reykjavik, Santa Maria, and Shanwick, excluding the Shannon and Brest ­Ocean Transition Areas. ICAO Doc 007 North Atlantic Operations and Airspace Manual provides detailed ­information on related aircraft and operational requirements.

    NORTH PACIFIC- An organized route system between the Alaskan west coast and Japan.

    NOT STANDARD- Varying from what is expected or published. For use in NOTAMs only.

    NOT STD-

    (See NOT STANDARD.)

    NOTAM-

    (See NOTICE TO AIRMEN.)

    NOTAM [ICAO]- 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.

17. I Distribution- Distribution by means of telecommunication.
18. II Distribution- Distribution by means other than telecommunications.

    NOTICE TO AIRMEN (NOTAM)- 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.

19. NOTAM (D)- A NOTAM given (in addition to local dissemination) distant dissemination beyond the area ­of responsibility of the Flight Service Station. These NOTAMs will be stored and available until canceled.
20. FDC NOTAM- A NOTAM regulatory in nature, transmitted by USNOF and given system wide ­dissemination.

    (See ICAO term NOTAM.)

    NRR-

    (See NON-RESTRICTIVE ROUTING.)

    NRS-

    (See NAVIGATION REFERENCE SYSTEM.)

    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.

    (See TRAFFIC ADVISORIES.)