Pilot/Controller Glossary

a. 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. 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.
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.
(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:
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.

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.