Glossary
Pilot/Controller Glossary

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:
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.
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.
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.

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.
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-

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.

(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:
a. 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