(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:
a. Nonradar Approach. Used to describe instru‐
ment 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.
(See FINAL APPROACH COURSE.)
(See FINAL APPROACH‐IFR.)
(See INSTRUMENT APPROACH
PROCEDURE.)
(See RADAR APPROACH.)
b. Nonradar Approach Control. An ATC facility
providing approach control service without the use of
radar.
(See APPROACH CONTROL FACILITY.)
(See APPROACH CONTROL SERVICE.)
c. 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
Pilot/Controller Glossary 2/14/08
PCG N-3
established or has been terminated due to a lack of
radar service to the airport.
(See RADAR ARRIVAL.)
(See RADAR SERVICE.)
d. 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.)
e. 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.)
(See ICAO term NONRADAR SEPARATION.)
NONRADAR SEPARATION - The separa‐
tion used when aircraft position information is
derived from sources other than radar.
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(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:
a. Common Route/Portion. That segment of a
North American Route between the inland navigation
facility and the coastal fix.
b. Noncommon Route/Portion. That segment of a
North American Route between the inland navigation
facility and a designated North American terminal.
c. Inland Navigation Facility. A navigation aid on
a North American Route at which the common route
and/or the noncommon route begins or ends.
d. 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 MARK- A beacon data block sent by the
host computer to be displayed by the ARTS on a 360
degree bearing at a locally selected radar azimuth and
distance. The North Mark is used to ensure correct
range/azimuth orientation during periods of
CENRAP.
NORTH PACIFIC- An organized route system
between the Alaskan west coast and Japan.
NOTAM(See NOTICE TO AIRMEN.)
NOTAM - 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.
a. I Distribution- Distribution by means of
telecommunication.
b. II Distribution- Distribution by means other
than telecommunications.
NOTIC E TO AIR MEN- A notice containing
information (not known sufficiently in advance to
publicize by other means) concerning the establish‐
ment, 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.
a. 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.
b. NOTAM(L)- A NOTAM given local disse‐
mination by voice and other means, such as
telautograph and telephone, to satisfy local user
requirements.
c. FDC NOTAM- A NOTAM regulatory in
nature, transmitted by USNOF and given system
wide dissemination.
(See ICAO term NOTAM.)
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PCG N-4
NOTIC ES TO AIR MEN PUBLIC ATION- 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 supplem ental data to other
aeronautical publications. The contraction NTAP is
used in NOTAM text.
(See NOTICE TO AIRMEN.)
NRR(See NON-RESTRICTIVE ROUTING.)
NRS(See NAVIGATION REFERENCE SYSTEM.)
NTAP(See NOTICES TO AIRMEN PUBLICATION.)
NUMEROUS TARGETS VICINITY (LOCA‐
TION)- A traffic advisory issued by ATC to advise
pilots that targets on the radar scope are too numerous
to issue individually.
(See TRAFFIC ADVISORIES.)
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O
OBSTACLE- An existing object, object of natural
growth, or terrain at a fixed geographical location or
which may be expected at a fixed location within a
prescribed area with reference to which vertical
clearance is or must be provided during flight
operation.
OBSTACLE DEPARTURE PROCEDURE (ODP)-
A preplanned instrument flight rule (IFR) departure
procedure printed for pilot use in textual or graphic
form to provide obstruction clearance via the least
onerous route from the term inal area to the
appropriate en route structure. ODPs are recom‐
mended for obstruction clearance and may be flown
without ATC clearance unless an alternate departure
procedure (SID or radar vector) has been specifically
assigned by ATC.
(See IFR TAKEOFF MINIMUMS AND
DEPARTURE PROCEDURES.)
(See STANDARD INSTRUMENT
DEPARTURES.)
(Refer to AIM.)
OBSTACLE FREE ZONE- The OFZ is a three
dimensional volume of airspace which protects for
the transition of aircraft to and from the runway. The
OFZ clearing standard precludes taxiing and parked
airplanes and object penetrations, except for
frangible NAVAID locations that are fixed by
function. Additionally, vehicles, equipment, and
personnel may be authorized by air traffic control to
enter the area using the provisions of FAAO JO
7110.65, Para 3-1-5, VEHICLES/EQUIPMENT/
PERSONNEL ON RUNWAYS. The runway OFZ
and when applicable, the inner‐approach OFZ, and
the inner‐transitional OFZ, comprise the OFZ.
a. Runway OFZ. The runway OFZ is a defined
volume of airspace centered above the runway. The
runway OFZ is the airspace above a surface whose
elevation at any point is the same as the elevation of
the nearest point on the runway centerline. The
runway OFZ extends 200 feet beyond each end of the
runway. The width is as follows: 1. For runways serving large airplanes, the
greater of:
(a) 400 feet, or
(b) 180 feet, plus the wingspan of the most
demanding airplane, plus 20 feet per 1,000 feet of
airport elevation.
2. For runways serving only small airplanes:
(a) 300 feet for precision instrument run‐
ways.
(b) 250 feet for other runways serving small
airplanes with approach speeds of 50 knots, or more.
(c) 120 feet for other runways serving small
airplanes with approach speeds of less than 50 knots.
b. Inner‐approach OFZ. The inner‐approach OFZ
is a defined volume of airspace centered on the
approach area. The inner‐approach OFZ applies only
to runways with an approach lighting system. The
inner‐approach OFZ begins 200 feet from the runway
threshold at the same elevation as the runway
threshold and extends 200 feet beyond the last light
unit in the approach lighting system. The width of the
inner‐approach OFZ is the same as the runway OFZ
and rises at a slope of 50 (horizontal) to 1 (vertical)
from the beginning.
c. Inner‐transitional OFZ. The inner transitional
surface OFZ is a defined volume of airspace along the
sides of the runway and inner‐approach OFZ and
applies only to precision instrument runways. The
inner‐transitional surface OFZ slopes 3 (horizontal)
to 1 (vertical) out from the edges of the runway OFZ
and inner‐approach OFZ to a height of 150 feet above
the established airport elevation.
(Refer to AC 150/5300‐13, Chapter 3.)
(Refer to FAAO JO 7110.65, Para 3-1-5,
VEHICLES/EQUIPMENT/PERSONNEL ON
RUNWAYS.)
OBSTRUCTION- Any object/obstacle exceeding
the obstruction standards specified by 14 CFR
Part 77, Subpart C.
OBSTRUCTION LIGHT- A light or one of a group
of lights, usually red or white, frequently mounted on
a surface structure or natural terrain to warn pilots of
the presence of an obstruction.
OCEANIC AIRSPACE- Airspace over the oceans of
the world, considered international airspace, where
oceanic separation and procedures per the Interna‐
tional Civil Aviation Organization are applied.
Responsibility for the provisions of air traffic control
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PCG O-2
service in this airspace is delegated to various
countries, based generally upon geographic proximi‐
ty and the availability of the required resources.
OCEANIC DISPLAY AND PLANNING SYS‐
TEM- An automated digital display system which
provides flight data processing, conflict probe, and
situation display for oceanic air traffic control.
OCEANIC NAVIGATIONAL ERROR REPORT- A
report filed when an aircraft exiting oceanic airspace
has been observed by radar to be off course. ONER
reporting parameters and procedures are contained in
FAAO 7110.82, Monitoring of Navigational Perfor‐
mance In Oceanic Areas.
OCEANIC PUBLISHED ROUTE- A route estab‐
lished in international airspace and charted or
described in flight information publications, such as
Route Charts, DOD Enroute Charts, Chart Supple‐
ments, NOTAMs, and Track Messages.
OCEANIC TRANSITION ROUTE- An ATS route
established for the purpose of transitioning aircraft
to/from an organized track system.
ODAPS(See OCEANIC DISPLAY AND PLANNING
SYSTEM.)
ODP(See OBSTACLE DEPARTURE PROCEDURE.)
OFF COURSE- A term used to describe a situation
where an aircraft has reported a position fix or is
observed on radar at a point not on the ATC‐approved
route of flight.
OFF‐ROUTE VECTOR- A vector by ATC which
takes an aircraft off a previously assigned route.
Altitudes assigned by ATC during such vectors
provide required obstacle clearance.
OFFSET PARALLEL RUNWAYS- Staggered
runways having centerlines which are parallel.
OFFSHORE/CONTROL AIRSPACE AREA- That
portion of airspace between the U.S. 12 NM limit and
the oceanic CTA/FIR boundary within which air
traffic control is exercised. These areas are
established to provide air traffic control services.
Offshore/Control Airspace Areas may be classified
as either Class A airspace or Class E airspace.
OFT(See OUTER FIX TIME.)
OM(See OUTER MARKER.)
OMEGA- An RNAV system designed for long‐range
navigation based upon ground‐based electronic
navigational aid signals.
ON COURSEa. Used to indicate that an aircraft is established on
the route centerline.
b. Used by ATC to advise a pilot making a radar
approach that his/her aircraft is lined up on the final
approach course.
(See ON‐COURSE INDICATION.)
ON‐COURSE INDICATION- An indication on an
instrument, which provides the pilot a visual means
of determining that the aircraft is located on the
centerline of a given navigational track, or an
indication on a radar scope that an aircraft is on a
given track.
ONE‐MINUTE WEATHER- The most recent one
minute updated weather broadcast received by a pilot
from an uncontrolled airport ASOS/AWOS.
ONER(See OCEANIC NAVIGATIONAL ERROR
REPORT.)
OPERATIONAL(See DUE REGARD.)
OPPOSITE DIRECTION AIRCRAFT- Aircraft are
operating in opposite directions when:
a. They are following the same track in reciprocal
directions; or
b. Their tracks are parallel and the aircraft are
flying in reciprocal directions; or
c. Their tracks intersect at an angle of more than
135.
OPTION APPROACH- An approach requested and
conducted by a pilot which will result in either a
touch‐and‐go, missed approach, low approach,
stop‐and‐go, or full stop landing.
(See CLEARED FOR THE OPTION.)
(Refer to AIM.)
ORGANIZED TRACK SYSTEM- A series of ATS
routes which are fixed and charted; i.e., CEP,
NOPAC, or flexible and described by NOTAM; i.e.,
NAT TRACK MESSAGE.
OROCA- An off‐route altitude which provides
obstruction clearance with a 1,000 foot buffer in
Pilot/Controller Glossary 2/14/08
PCG O-3
nonmountainous terrain areas and a 2,000 foot buffer
in designated mountainous areas within the United
States. This altitude may not provide signal coverage
from ground‐based navigational aids, air traffic
control radar, or communications coverage.
OTR(See OCEANIC TRANSITION ROUTE.)
OTS(See ORGANIZED TRACK SYSTEM.)
OUT- The conversation is ended and no response is
expected.
OUTER AREA (associated with Class C airspace)-
Nonregulatory airspace surrounding designated
Class C airspace airports wherein ATC provides radar
vectoring and sequencing on a full‐time basis for all
IFR and participating VFR aircraft. The service
provided in the outer area is called Class C service
which includes: IFR/IFR-standard IFR separation;
IFR/VFR-traffic advisories and conflict resolution;
and VFR/VFR-traffic advisories and, as appropriate,
safety alerts. The normal radius will be 20 nautical
miles with some variations based on site‐specific
requirements. The outer area extends outward from
the primary Class C airspace airport and extends from
the lower limits of radar/radio coverage up to the
ceiling of the approach control's delegated airspace
excluding the Class C charted area and other airspace
as appropriate.
(See CONFLICT RESOLUTION.)
(See CONTROLLED AIRSPACE.)
OUTER COMPASS LOCATOR(See COMPASS LOCATOR.)
OUTER FIX- A general term used within ATC to
describe fixes in the terminal area, other than the final
approach fix. Aircraft are normally cleared to these
fixes by an Air Route Traffic Control Center or an
Approach Control Facility. Aircraft are normally
cleared from these fixes to the final approach fix or
final approach course.
OR
OUTER FIX- An adapted fix along the converted
route of flight, prior to the meter fix, for which
crossing times are calculated and displayed in the
metering position list.
OUTER FIX ARC- A semicircle, usually about a
50-70 mile radius from a meter fix, usually in high
altitude, which is used by CTAS/HOST to calculate
outer fix times and determine appropriate sector
meter list assignments for aircraft on an established
arrival route that will traverse the arc.
OUTER FIX TIME- A calculated time to depart the
outer fix in order to cross the vertex at the ACLT. The
time reflects descent speed adjustments and any
applicable delay time that must be absorbed prior to
crossing the meter fix.
OUTER MARKER- A marker beacon at or near the
glideslope intercept altitude of an ILS approach. It is
keyed to transmit two dashes per second on a 400 Hz
tone, which is received aurally and visually by
compatible airborne equipment. The OM is normally
located four to seven miles from the runway threshold
on the extended centerline of the runway.
(See INSTRUMENT LANDING SYSTEM.)
(See MARKER BEACON.)
(Refer to AIM.)
OVER- My transmission is ended; I expect a
response.
OVERHEAD MANEUVER- A series of predeter‐
mined maneuvers prescribed for aircraft (often in
formation) for entry into the visual flight rules (VFR)
traffic pattern and to proceed to a landing. An
overhead maneuver is not an instrument flight rules
(IFR) approach procedure. An aircraft executing an
overhead maneuver is considered VFR and the IFR
flight plan is cancelled when the aircraft reaches the
“initial point” on the initial approach portion of the
maneuver. The pattern usually specifies the
following:
a. The radio contact required of the pilot.
b. The speed to be maintained.
c. An initial approach 3 to 5 miles in length.
d. An elliptical pattern consisting of two 180
degree turns.
e. A break point at which the first 180 degree turn
is started.
f. The direction of turns.
g. Altitude (at least 500 feet above the convention‐
al pattern).
h. A “Roll‐out” on final approach not less than 1/4
mile from the landing threshold and not less than 300
feet above the ground.
Pilot/Controller Glossary 2/14/08
PCG O-4
OVERLYING CENTER- The ARTCC facility that
is responsible for arrival/departure operations at a
specific terminal.
Pilot/Controller Glossary 2/14/08
PCG P-1
P
P TIME(See PROPOSED DEPARTURE TIME.)
P‐ACP(See PREARRANGED COORDINATION
PROCEDURES.)
PAN‐PAN- The international radio‐telephony urgen‐
cy signal. When repeated three times, indicates
uncertainty or alert followed by the nature of the
urgency.
(See MAYDAY.)
(Refer to AIM.)
PAR(See PRECISION APPROACH RADAR.)
PAR -
(See ICAO Term PRECISION APPROACH
RADAR.)
PARALLEL ILS APPROACHES- Approaches to
parallel runways by IFR aircraft which, when
established inbound toward the airport on the
adjacent final approach courses, are radar‐separated
by at least 2 miles.
(See FINAL APPROACH COURSE.)
(See SIMULTANEOUS ILS APPROACHES.)
PARALLEL MLS APPROACHES(See PARALLEL ILS APPROACHES.)
PARALLEL OFFSET ROUTE- A parallel track to
the left or right of the designated or established
airway/route. Normally associated with Area Navi‐
gation (RNAV) operations.
(See AREA NAVIGATION.)
PARALLEL RUNWAYS- Two or more runways at
the same airport whose centerlines are parallel. In
addition to runway number, parallel runways are
designated as L (left) and R (right) or, if three parallel
runways exist, L (left), C (center), and R (right).
PBCT(See PROPOSED BOUNDARY CROSSING
TIME.)
PDC(See PRE-DEPARTURE CLEARANCE.)
PERMANENT ECHO- Radar signals reflected from
fixed objects on the earth's surface; e.g., buildings,
towers, terrain. Permanent echoes are distinguished
from “ground clutter” by being definable locations
rather than large areas. Under certain conditions they
may be used to check radar alignment.
PHOTO RECONNAISSANCE- Military activity
that requires locating individual photo targets and
navigating to the targets at a preplanned angle and
altitude. The activity normally requires a lateral route
width of 16 NM and altitude range of 1,500 feet to
10,000 feet AGL.
PILOT BRIEFING- A service provided by the FSS
to assist pilots in flight planning. Briefing items may
include weather information, NOTAMS, military
activities, flow control information, and other items
as requested.
(Refer to AIM.)
PILOT IN COMMAND- The pilot responsible for
the operation and safety of an aircraft during flight
time.
(Refer to 14 CFR Part 91.)
PILOT WEATHER REPORT- A report of meteoro‐
logical phenomena encountered by aircraft in flight.
(Refer to AIM.)
PILOT'S DISCRETION- When used in conjunc‐
tion with altitude assignments, means that ATC has
offered the pilot the option of starting climb or
descent whenever he/she wishes and conducting the
climb or descent at any rate he/she wishes. He/she
may temporarily level off at any intermediate
altitude. However, once he/she has vacated an
altitude, he/she may not return to that altitude.
PIREP(See PILOT WEATHER REPORT.)
PITCH POINT- A fix/waypoint that serves as a
transition point from a departure procedure or the low
altitude ground-based navigation structure into the
high altitude waypoint system.
PLANS DISPLAY- A display available in URET
that provides detailed flight plan and predicted
conflict information in textual format for requested
Current Plans and all Trial Plans.
(See USER REQUEST EVALUATION TOOL.)
Pilot/Controller Glossary 2/14/08
PCG P-2
POFZ(See PRECISION OBSTACLE FREE ZONE.)
POINT OUT(See RADAR POINT OUT.)
POINT-TO-POINT (PTP)- A level of NRR service
for aircraft that is based on traditional waypoints in
their FMSs or RNAV equipage.
POLAR TRACK STRUCTURE- A system of
organized routes between Iceland and Alaska which
overlie Canadian MNPS Airspace.
POSITION AND HOLD- Used by ATC to inform a
pilot to taxi onto the departure runway in takeoff
position and hold. It is not authorization for takeoff.
It is used when takeoff clearance cannot immediately
be issued because of traffic or other reasons.
(See CLEARED FOR TAKEOFF.)
POSITION REPORT- A report over a known
location as transmitted by an aircraft to ATC.
(Refer to AIM.)
POSITION SYMBOL- A computer‐generated
indication shown on a radar display to indicate the
mode of tracking.
POSITIVE CONTROL- The separation of all air
traffic within designated airspace by air traffic
control.
PRACTICE INSTRUMENT APPROACH- An
instrument approach procedure conducted by a VFR
or an IFR aircraft for the purpose of pilot training or
proficiency demonstrations.
PRE-DEPARTURE CLEARANCE- An application
with the Terminal Data Link System (TDLS) that
provides clearance information to subscribers,
through a service provider, in text to the cockpit or
gate printer.
PREARRANGED COORDINATION- A standard‐
ized procedure which permits an air traffic controller
to enter the airspace assigned to another air traffic
controller without verbal coordination. The proce‐
dures are defined in a facility directive which ensures
standard separation between aircraft.
PREARRANGED COORDINATION PROCE‐
DURES- A facility's standardized procedure that
describes the process by which one controller shall
allow an aircraft to penetrate or transit another
controller's airspace in a manner that assures standard
separation without individual coordination for each
aircraft.
PRECIP ITATION- Any or all form s of water
particles (rain, sleet, hail, or snow) that fall from the
atmosphere and reach the surface.
PRECIPITATION RADAR WEATHER DE‐
SCRIPTIONS - Existing radar systems cannot detect
turbulence. However, there is a direct correlation
between the degree of turbulence and other weather
features associated with thunderstorms and the
weather radar precipitation intensity. Controllers will
issue (where capable) precipitation intensity as
observed by radar when using weather and radar
processor (WARP) or NAS ground based digital
radars with weather capabilities. When precipitation
intensity information is not available, the intensity
will be described as UNKNOWN. When intensity
levels can be determined, they shall be described as:
a. LIGHT (< 30 dBZ)
b. MODERATE (30 to 40 dBZ)
c. HEAVY (> 40 to 50 dBZ)
d. EXTREME (> 50 dBZ)
(Refer to AC 00-45, Aviation Weather Services.)
PRECISION APPROACH(See PRECISION APPROACH PROCEDURE.)
PRECISION APPROACH PROCEDURE- A stan‐
dard instrument approach procedure in which an
electronic glideslope/glidepath is provided; e.g., ILS,
MLS, and PAR.
(See INSTRUMENT LANDING SYSTEM.)
(See MICROWAVE LANDING SYSTEM.)
(See PRECISION APPROACH RADAR.)
PRECISION APPROACH RADAR- Radar equip‐
ment in some ATC facilities operated by the FAA
and/or the military services at joint‐use civil/military
locations and separate military installations to detect
and display azimuth, elevation, and range of aircraft
on the final approach course to a runway. This
equipment may be used to monitor certain nonradar
approaches, but is primarily used to conduct a
precision instrument approach (PAR) wherein the
controller issues guidance instructions to the pilot
based on the aircraft's position in relation to the final
approach course (azimuth), the glidepath (elevation),
Pilot/Controller Glossary 2/14/08
PCG P-3
and the distance (range) from the touchdown point on
the runway as displayed on the radar scope.
Note:The abbreviation “PAR” is also used to
denote preferential arrival routes in ARTCC
computers.
(See GLIDEPATH.)
(See PAR.)
(See PREFERENTIAL ROUTES.)
(See ICAO term PRECISION APPROACH
RADAR.)
(Refer to AIM.)
PRECISION APPROACH RADAR - Pri‐
mary radar equipment used to determine the position
of an aircraft during final approach, in terms of lateral
and vertical deviations relative to a nominal approach
path, and in range relative to touchdown.
Note:Precision approach radars are designed to
enable pilots of aircraft to be given guidance by
radio communication during the final stages of the
approach to land.
PRECISION OBSTACLE FREE ZONE (POFZ)-
An 800 foot wide by 200 foot long area centered on
the runway centerline adjacent to the threshold
designed to protect aircraft flying precision
approaches from ground vehicles and other aircraft
when ceiling is less than 250 feet or visibility is less
than 3/4 statute mile (or runway visual range below
4,000 feet.)
PRECISION RUNWAY MONITOR (PRM)- Pro‐
vides air traffic controllers with high precision
secondary surveillance data for aircraft on final
approach to parallel runways that have extended
centerlines separated by less than 4,300 feet. High
resolution color monitoring displays (FMA) are
required to present surveillance track data to
controllers along with detailed maps depicting
approaches and no transgression zone.
PREFERENTIAL ROUTES- Preferential routes
(PDRs, PARs, and PDARs) are adapted in ARTCC
computers to accomplish inter/intrafacility controller
coordination and to assure that flight data is posted at
the proper control positions. Locations having a need
for these specific inbound and outbound routes
normally publish such routes in local facility
bulletins, and their use by pilots minimizes flight
plan route amendments. When the workload or traffic
situation permits, controllers normally provide radar
vectors or assign requested routes to minimize
circuitous routing. Preferential routes are usually
confined to one ARTCC's area and are referred to by
the following names or acronyms:
a. Preferential Departure Route (PDR). A specific
departure route from an airport or terminal area to an
en route point where there is no further need for flow
control. It may be included in an Instrument
Departure Procedure (DP) or a Preferred IFR Route.
b. Preferential Arrival Route (PAR). A specific
arrival route from an appropriate en route point to an
airport or terminal area. It may be included in a
Standard Terminal Arrival (STAR) or a Preferred IFR
Route. The abbreviation “PAR” is used primarily
within the ARTCC and should not be confused with
the abbreviation for Precision Approach Radar.
c. Preferential Departure and Arrival Route
(PDAR). A route between two terminals which are
within or immediately adjacent to one ARTCC's area.
PDARs are not synonymous with Preferred IFR
Routes but may be listed as such as they do
accomplish essentially the same purpose.
(See PREFERRED IFR ROUTES.)
PREFERRED IFR ROUTES- Routes established
between busier airports to increase system efficiency
and capacity. They normally extend through one or
more ARTCC areas and are designed to achieve
balanced traffic flows among high density terminals.
IFR clearances are issued on the basis of these routes
except when severe weather avoidance procedures or
other factors dictate otherwise. Preferred IFR Routes
are listed in the Airport/Facility Directory. If a flight
is planned to or from an area having such routes but
the departure or arrival point is not listed in the
Airport/Facility Directory, pilots may use that part of
a Preferred IFR Route which is appropriate for the
departure or arrival point that is listed. Preferred IFR
Routes are correlated with DPs and STARs and may
be defined by airways, jet routes, direct routes
between NAVAIDs, Waypoints, NAVAID radials/
DME, or any combinations thereof.
(See CENTER'S AREA.)
(See INSTRUMENT DEPARTURE
PROCEDURE.)
(See PREFERENTIAL ROUTES.)
(See STANDARD TERMINAL ARRIVAL.)
(Refer to AIRPORT/FACILITY DIRECTORY.)
(Refer to NOTICES TO AIRMEN PUBLICATION.)
PRE‐FLIGHT PILOT BRIEFING(See PILOT BRIEFING.)
PREVAILING VISIBILITY(See VISIBILITY.)
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PCG P-4
PRIMARY RADAR TARGET- An analog or digital
target, exclusive of a secondary radar target,
presented on a radar display.
PRM(See ILS PRM APPROACH and PRECISION
RUNWAY MONITOR.)
PROCEDURE TURN- The maneuver prescribed
when it is necessary to reverse direction to establish
an aircraft on the intermediate approach segment or
final approach course. The outbound course,
direction of turn, distance within which the turn must
be completed, and minimum altitude are specified in
the procedure. However, unless otherwise restricted,
the point at which the turn may be commenced and
the type and rate of turn are left to the discretion of the
pilot.
(See ICAO term PROCEDURE TURN.)
PROCEDURE TURN - A maneuver in
which a turn is made away from a designated track
followed by a turn in the opposite direction to permit
the aircraft to intercept and proceed along the
reciprocal of the designated track.
Note 1:Procedure turns are designated “left” or
“right” according to the direction of the initial turn.
Note 2:Procedure turns may be designated as
being made either in level flight or while
descending, according to the circumstances of
each individual approach procedure.
PROCEDURE TURN INBOUND- That point of a
procedure turn maneuver where course reversal has
been completed and an aircraft is established inbound
on the intermediate approach segment or final
approach course. A report of “procedure turn
inbound” is normally used by ATC as a position
report for separation purposes.
(See FINAL APPROACH COURSE.)
(See PROCEDURE TURN.)
(See SEGMENTS OF AN INSTRUMENT
APPROACH PROCEDURE.)
PROFILE DESCENT- An uninterrupted descent
(except where level flight is required for speed
adjustment; e.g., 250 knots at 10,000 feet MSL) from
cruising altitude/level to interception of a glideslope
or to a minimum altitude specified for the initial or
intermediate approach segment of a nonprecision
instrument approach. The profile descent normally
term inates at the approach gate or where the
glideslope or other appropriate minimum altitude is
intercepted.
PROGRESS REPORT(See POSITION REPORT.)
PROGRESSIVE TAXI- Precise taxi instructions
given to a pilot unfamiliar with the airport or issued
in stages as the aircraft proceeds along the taxi route.
PROHIBITED AREA(See SPECIAL USE AIRSPACE.)
(See ICAO term PROHIBITED AREA.)
PROHIBITED AREA - An airspace of
defined dimensions, above the land areas or territorial
waters of a State, within which the flight of aircraft
is prohibited.
PROPOSED BOUNDARY CROSSING TIME-
Each center has a PBCT parameter for each internal
airport. Proposed internal flight plans are transmitted
to the adjacent center if the flight time along the
proposed route from the departure airport to the
center boundary is less than or equal to the value of
PBCT or if airport adaptation specifies transmission
regardless of PBCT.
PROPOSED DEPARTURE TIME- The time that the
aircraft expects to become airborne.
PROTECTED AIRSPACE- The airspace on either
side of an oceanic route/track that is equal to one‐half
the lateral separation minimum except where
reduction of protected airspace has been authorized.
PT(See PROCEDURE TURN.)
PTP(See POINT-TO-POINT.)
PTS(See POLAR TRACK STRUCTURE.)
PUBLISHED ROUTE- A route for which an IFR
altitude has been established and published; e.g.,
Federal Airways, Jet Routes, Area Navigation
Routes, Specified Direct Routes.
Pilot/Controller Glossary 2/14/08
PCG Q-1
Q
Q ROUTE- `Q' is the designator assigned to
published RNAV routes used by the United States.
QNE- The barometric pressure used for the standard
altimeter setting (29.92 inches Hg.).
QNH- The barometric pressure as reported by a
particular station.
QUADRANT- A quarter part of a circle, centered on
a NAVAID, oriented clockwise from magnetic north
as follows: NE quadrant 000‐089, SE quadrant
090‐179, SW quadrant 180‐269, NW quadrant
270‐359.
QUEUING(See STAGING/QUEUING.)
QUICK LOOK- A feature of the EAS and ARTS
which provides the controller the capability to
display full data blocks of tracked aircraft from other
control positions.
Pilot/Controller Glossary 2/14/08
PCG R-1
R
RAA(See REMOTE AIRPORT ADVISORY.)
RADAR- A device which, by measuring the time
interval between transmission and reception of radio
pulses and correlating the angular orientation of the
radiated antenna beam or beams in azimuth and/or
elevation, provides information on range, azimuth,
and/or elevation of objects in the path of the
transmitted pulses.
a. Primary Radar- A radar system in which a
minute portion of a radio pulse transmitted from a site
is reflected by an object and then received back at that
site for processing and display at an air traffic control
facility.
b. Secondary Radar/Radar Beacon (ATCRBS)- A
radar system in which the object to be detected is
fitted with cooperative equipment in the form of a
radio receiver/transmitter (transponder). Radar
pulses transmitted from the searching transmitter/re‐
ceiver (interrogator) site are received in the
cooperative equipment and used to trigger a
distinctive transmission from the transponder. This
reply transmission, rather than a reflected signal, is
then received back at the transmitter/receiver site for
processing and display at an air traffic control facility.
(See INTERROGATOR.)
(See TRANSPONDER.)
(See ICAO term RADAR.)
(Refer to AIM.)
RADAR - A radio detection device which
provides information on range, azimuth and/or
elevation of objects.
a. Primary Radar- Radar system which uses
reflected radio signals.
b. Secondary Radar- Radar system wherein a
radio signal transmitted from a radar station initiates
the transmission of a radio signal from another
station.
RADAR ADVISORY- The provision of advice and
information based on radar observations.
(See ADVISORY SERVICE.)
RADAR ALTIMETER(See RADIO ALTIMETER.)
RADAR APPROACH- An instrument approach
procedure which utilizes Precision Approach Radar
(PAR) or Airport Surveillance Radar (ASR).
(See AIRPORT SURVEILLANCE RADAR.)
(See INSTRUMENT APPROACH
PROCEDURE.)
(See PRECISION APPROACH RADAR.)
(See SURVEILLANCE APPROACH.)
(See ICAO term RADAR APPROACH.)
(Refer to AIM.)
RADAR APPROACH - An approach,
executed by an aircraft, under the direction of a radar
controller.
RADAR APPROACH CONTROL FACILITY- A
terminal ATC facility that uses radar and nonradar
capabilities to provide approach control services to
aircraft arriving, departing, or transiting airspace
controlled by the facility.
(See APPROACH CONTROL SERVICE.)
a. Provides radar ATC services to aircraft
operating in the vicinity of one or more civil and/or
military airports in a terminal area. The facility may
provide services of a ground controlled approach
(GCA); i.e., ASR and PAR approaches. A radar
approach control facility may be operated by FAA,
USAF, US Army, USN, USMC, or jointly by FAA
and a military service. Specific facility nomencla‐
tures are used for administrative purposes only and
are related to the physical location of the facility and
the operating service generally as follows:
1. Army Radar Approach Control (ARAC)
(Army).
2. Radar Air Traffic Control Facility (RATCF)
(Navy/FAA).
3. Radar Approach Control (RAPCON) (Air
Force/FAA).
4. Term inal Radar Approach Control
(TRACON) (FAA).
5. Air Traffic Control Tower (ATCT) (FAA).
(Only those towers delegated approach control
authority.)
RADAR ARRIVAL- An aircraft arriving at an
airport served by a radar facility and in radar contact
with the facility.
(See NONRADAR.)
Pilot/Controller Glossary 2/14/08
PCG R-2
RADAR BEACON(See RADAR.)
RADAR CLUTTER - The visual indication
on a radar display of unwanted signals.
RADAR CONTACTa. Used by ATC to inform an aircraft that it is
identified on the radar display and radar flight
following will be provided until radar identification
is terminated. Radar service may also be provided
within the limits of necessity and capability. When a
pilot is inform ed of “radar contact,” he/she
automatically discontinues reporting over compulso‐
ry reporting points.
(See RADAR CONTACT LOST.)
(See RADAR FLIGHT FOLLOWING.)
(See RADAR SERVICE.)
(See RADAR SERVICE TERMINATED.)
(Refer to AIM.)
b. The term used to inform the controller that the
aircraft is identified and approval is granted for the
aircraft to enter the receiving controllers airspace.
(See ICAO term RADAR CONTACT.)
RADAR CONTACT - The situation which
exists when the radar blip or radar position symbol of
a particular aircraft is seen and identified on a radar
display.
RADAR CONTACT LOST- Used by ATC to inform
a pilot that radar data used to determine the aircraft's
position is no longer being received, or is no longer
reliable and radar service is no longer being provided.
The loss may be attributed to several factors
including the aircraft merging with weather or ground
clutter, the aircraft operating below radar line of sight
coverage, the aircraft entering an area of poor radar
return, failure of the aircraft transponder, or failure of
the ground radar equipment.
(See CLUTTER.)
(See RADAR CONTACT.)
RADAR ENVIRONMENT- An area in which radar
service may be provided.
(See ADDITIONAL SERVICES.)
(See RADAR CONTACT.)
(See RADAR SERVICE.)
(See TRAFFIC ADVISORIES.)
RADAR FLIGHT FOLLOWING- The observation
of the progress of radar identified aircraft, whose
primary navigation is being provided by the pilot,
wherein the controller retains and correlates the
aircraft identity with the appropriate target or target
symbol displayed on the radar scope.
(See RADAR CONTACT.)
(See RADAR SERVICE.)
(Refer to AIM.)
RADAR IDENTIFIC ATION- The process of
ascertaining that an observed radar target is the radar
return from a particular aircraft.
(See RADAR CONTACT.)
(See RADAR SERVICE.)
(See ICAO term RADAR IDENTIFICATION.)
RADAR IDENTIFICATION - The process
of correlating a particular radar blip or radar position
symbol with a specific aircraft.
RADAR IDENTIFIED AIRCRAFT- An aircraft, the
position of which has been correlated with an
observed target or symbol on the radar display.
(See RADAR CONTACT.)
(See RADAR CONTACT LOST.)
RADAR MONITORING(See RADAR SERVICE.)
RADAR NAVIGATIONAL GUIDANCE(See RADAR SERVICE.)
RADAR POINT OUT- An action taken by a
controller to transfer the radar identification of an
aircraft to another controller if the aircraft will or may
enter the airspace or protected airspace of another
controller and radio communications will not be
transferred.
RADAR REQUIRED- A term displayed on charts
and approach plates and included in FDC NOTAMs
to alert pilots that segments of either an instrument
approach procedure or a route are not navigable
because of either the absence or unusability of a
NAVAID. The pilot can expect to be provided radar
navigational guidance while transiting segments
labeled with this term.
(See RADAR ROUTE.)
(See RADAR SERVICE.)
RADAR ROUTE- A flight path or route over which
an aircraft is vectored. Navigational guidance and
altitude assignments are provided by ATC.
(See FLIGHT PATH.)
(See ROUTE.)
RADAR SEPARATION(See RADAR SERVICE.)
Pilot/Controller Glossary 2/14/08
PCG R-3
RADAR SERVICE- A term which encompasses one
or more of the following services based on the use of
radar which can be provided by a controller to a pilot
of a radar identified aircraft.
a. Radar Monitoring- The radar flight‐following
of aircraft, whose primary navigation is being
performed by the pilot, to observe and note deviations
from its authorized flight path, airway, or route.
When being applied specifically to radar monitoring
of instrument approaches; i.e., with precision
approach radar (PAR) or radar monitoring of
simultaneous ILS/MLS approaches, it includes
advice and instructions whenever an aircraft nears or
exceeds the prescribed PAR safety limit or
simultaneous ILS/MLS no transgression zone.
(See ADDITIONAL SERVICES.)
(See TRAFFIC ADVISORIES.)
b. Radar Navigational Guidance- Vectoring
aircraft to provide course guidance.
c. Radar Separation- Radar spacing of aircraft in
accordance with established minima.
(See ICAO term RADAR SERVICE.)
RADAR SERVICE - Term used to indicate
a service provided directly by means of radar.
a. Monitoring- The use of radar for the purpose of
providing aircraft with information and advice
relative to significant deviations from nominal flight
path.
b. Separation- The separation used when aircraft
position information is derived from radar sources.
RADAR SERVICE TERMINATED- Used by ATC
to inform a pilot that he/she will no longer be
provided any of the services that could be received
while in radar contact. Radar service is automatically
terminated, and the pilot is not advised in the
following cases:
a. An aircraft cancels its IFR flight plan, except
within Class B airspace, Class C airspace, a TRSA,
or where Basic Radar service is provided.
b. An aircraft conducting an instrument, visual, or
contact approach has landed or has been instructed to
change to advisory frequency.
c. An arriving VFR aircraft, receiving radar
service to a tower‐controlled airport within Class B
airspace, Class C airspace, a TRSA, or where
sequencing service is provided, has landed; or to all
other airports, is instructed to change to tower or
advisory frequency.
d. An aircraft completes a radar approach.
RADAR SURVEILLANCE- The radar observation
of a given geographical area for the purpose of
performing some radar function.
RADAR TRAFFIC ADVISORIES- Advisories
issued to alert pilots to known or observed radar
traffic which may affect the intended route of flight
of their aircraft.
(See TRAFFIC ADVISORIES.)
RADAR TRAFFIC INFORMATION SERVICE(See TRAFFIC ADVISORIES.)
RADAR VECTORING - Provision of
navigational guidance to aircraft in the form of
specific headings, based on the use of radar.
RADIAL- A magnetic bearing extending from a
VOR/VORTAC/TACAN navigation facility.
RADIOa. A device used for communication.
b. Used to refer to a flight service station; e.g.,
“Seattle Radio” is used to call Seattle FSS.
RADIO ALTIMETER- Aircraft equipment which
makes use of the reflection of radio waves from the
ground to determine the height of the aircraft above
the surface.
RADIO BEACON(See NONDIRECTIONAL BEACON.)
RADIO DETECTION AND RANGING(See RADAR.)
RADIO MAGNETIC INDICATOR- An aircraft
navigational instrument coupled with a gyro compass
or similar compass that indicates the direction of a
selected NAVAID and indicates bearing with respect
to the heading of the aircraft.
RAIS(See REMOTE AIRPORT INFORMATION
SERVICE.)
RAMP(See APRON.)
RANDOM ALTITUDE- An altitude inappropriate
for direction of flight and/or not in accordance with
FAAO JO 7110.65, Para 4-5-1, VERTIC AL
SEPARATION MINIMA.
Pilot/Controller Glossary 2/14/08
PCG R-4
RANDOM ROUTE- Any route not established or
charted/published or not otherwise available to all
users.
RC(See ROAD RECONNAISSANCE.)
RCAG(See REMOTE COMMUNICATIONS
AIR/GROUND FACILITY.)
RCC(See RESCUE COORDINATION CENTER.)
RCO(See REMOTE COMMUNICATIONS OUTLET.)
RCR(See RUNWAY CONDITION READING.)
READ BACK- Repeat my message back to me.
RECEIVER AUTONOMOUS INTEGRITY MON‐
ITORING (RAIM)- A technique whereby a civil
GNSS receiver/processor determines the integrity of
the GNSS navigation signals without reference to
sensors or non‐DoD integrity systems other than the
receiver itself. This determination is achieved by a
consistency check among redundant pseudorange
measurements.
RECEIVING CONTROLLER- A controller/facility
receiving control of an aircraft from another
controller/facility.
RECEIVING FACILITY(See RECEIVING CONTROLLER.)
RECONFORMANCE- The automated process of
bringing an aircraft's Current Plan Trajectory into
conformance with its track.
REDUCE SPEED TO (SPEED)-
(See SPEED ADJUSTMENT.)
REIL(See RUNWAY END IDENTIFIER LIGHTS.)
RELEASE TIME- A departure time restriction
issued to a pilot by ATC (either directly or through an
authorized relay) when necessary to separate a
departing aircraft from other traffic.
(See ICAO term RELEASE TIME.)
RELEASE TIME - Time prior to which an
aircraft should be given further clearance or prior to
which it should not proceed in case of radio failure.
REMOTE AIR PORT ADVIS ORY (RAA)- A
remote service which may be provided by facilities,
which are not located on the landing airport, but have
a discrete ground-to-air communication frequency
or tower frequency when the tower is closed,
automated weather reporting with voice available to
the pilot at the landing airport, and a continuous
ASOS/AWOS data display, other direct reading
instruments, or manual observation is available to the
AFSS specialist.
REMOTE AIRPORT INFORMATION SERVICE
(RAIS)- A temporary service provided by facilities,
which are not located on the landing airport, but have
communication capability and automated weather
reporting available to the pilot at the landing airport.
REMOTE COMMUNICATIONS AIR/GROUND
FACILITY- An unmanned VHF/UHF transmitter/
receiver facility which is used to expand ARTCC
air/ground communications coverage and to facilitate
direct contact between pilots and controllers. RCAG
facilities are sometimes not equipped with emergen‐
cy frequencies 121.5 MHz and 243.0 MHz.
(Refer to AIM.)
REMOTE COMMUNICATIONS OUTLET- An
unmanned communications facility remotely con‐
trolled by air traffic personnel. RCOs serve FSSs.
RTRs serve terminal ATC facilities. An RCO or RTR
may be UHF or VHF and will extend the
communication range of the air traffic facility. There
are several classes of RCOs and RTRs. The class is
determ ined by the number of transmitters or
receivers. Classes A through G are used primarily for
air/ground purposes. RCO and RTR class O
facilities are nonprotected outlets subject to
undetected and prolonged outages. RCO (O's) and
RTR (O's) were established for the express purpose
of providing ground‐to‐ground communications
between air traffic control specialists and pilots
located at a satellite airport for delivering en route
clearances, issuing departure authorizations, and
acknowledging instrument flight rules cancellations
or departure/landing times. As a secondary function,
they may be used for advisory purposes whenever the
aircraft is below the coverage of the primary
air/ground frequency.
REMOTE TRANSMITTER/RECEIVER(See REMOTE COMMUNICATIONS OUTLET.)
Pilot/Controller Glossary 2/14/08
PCG R-5
REPORT- Used to instruct pilots to advise ATC of
specified information; e.g., “Report passing Hamil‐
ton VOR.”
REPORTING POINT- A geographical location in
relation to which the position of an aircraft is
reported.
(See COMPULSORY REPORTING POINTS.)
(See ICAO term REPORTING POINT.)
(Refer to AIM.)
REPORTING POINT - A specified geo‐
graphical location in relation to which the position of
an aircraft can be reported.
REQUEST FULL ROUTE CLEARANCE- Used
by pilots to request that the entire route of flight be
read verbatim in an ATC clearance. Such request
should be made to preclude receiving an ATC
clearance based on the original filed flight plan when
a filed IFR flight plan has been revised by the pilot,
company, or operations prior to departure.
REQUIRED NAVIGATION PERFORMANCE
(RNP)– A statement of the navigational performance
necessary for operation within a defined airspace.
The following terms are commonly associated with
RNP:
a. Required Navigation Performance Level or
Type (RNP‐X). A value, in nautical miles (NM), from
the intended horizontal position within which an
aircraft would be at least 95‐percent of the total flying
time.
b. Required Navigation Performance (RNP)
Airspace. A generic term designating airspace, route
(s), leg (s), operation (s), or procedure (s) where
minimum required navigational performance (RNP)
have been established.
c. Actual Navigation Performance (ANP). A
measure of the current estimated navigational
performance. Also referred to as Estimated Position
Error (EPE).
d. Estimated Position Error (EPE). A measure of
the current estimated navigational performance. Also
referred to as Actual Navigation Performance (ANP).
e. Lateral Navigation (LNAV). A function of area
navigation (RNAV) equipment which calculates,
displays, and provides lateral guidance to a profile or
path.
f. Vertical Navigation (VNAV). A function of area
navigation (RNAV) equipment which calculates,
displays, and provides vertical guidance to a profile
or path.
RESCUE COORDINATION CENTER- A search
and rescue (SAR) facility equipped and manned to
coordinate and control SAR operations in an area
designated by the SAR plan. The U.S. Coast Guard
and the U.S. Air Force have responsibility for the
operation of RCCs.
(See ICAO term RESCUE CO‐ORDINATION
CENTRE.)
RESCUE CO‐ORDINATION CENTRE - A
unit responsible for promoting efficient organization
of search and rescue service and for coordinating the
conduct of search and rescue operations within a
search and rescue region.
RESOLUTION ADVISORY-A display indication
given to the pilot by the traffic alert and collision
avoidance systems (TCAS II) recommending a
maneuver to increase vertical separation relative to an
intruding aircraft. Positive, negative, and vertical
speed limit (VSL) advisories constitute the resolution
advisories. A resolution advisory is also classified as
corrective or preventive
RESTRICTED AREA(See SPECIAL USE AIRSPACE.)
(See ICAO term RESTRICTED AREA.)
RESTRICTED AREA - An airspace of
defined dimensions, above the land areas or territorial
waters of a State, within which the flight of aircraft
is restricted in accordance with certain specified
conditions.
RESUME NORMAL SPEED- Used by ATC to
advise a pilot that previously issued speed control
restrictions are deleted. An instruction to “resume
normal speed” does not delete speed restrictions that
are applicable to published procedures of upcoming
segments of flight, unless specifically stated by ATC.
This does not relieve the pilot of those speed
restrictions which are applicable to 14 CFR
Section 91.117.
RESUME OWN NAVIGATION- Used by ATC to
advise a pilot to resume his/her own navigational
responsibility. It is issued after completion of a radar
Pilot/Controller Glossary 2/14/08
PCG R-6
vector or when radar contact is lost while the aircraft
is being radar vectored.
(See RADAR CONTACT LOST.)
(See RADAR SERVICE TERMINATED.)
RMI(See RADIO MAGNETIC INDICATOR.)
RNAV(See AREA NAVIGATION.)
(See ICAO Term AREA NAVIGATION.)
RNAV APPROACH- An instrument approach
procedure which relies on aircraft area navigation
equipment for navigational guidance.
(See AREA NAVIGATION.)
(See INSTRUMENT APPROACH
PROCEDURE.)
ROAD RECONNAISSANCE- Military activity
requiring navigation along roads, railroads, and
rivers. Reconnaissance route/route segments are
seldom along a straight line and normally require a
lateral route width of 10 NM to 30 NM and an altitude
range of 500 feet to 10,000 feet AGL.
ROGER- I have received all of your last
transmission. It should not be used to answer a
question requiring a yes or a no answer.
(See AFFIRMATIVE.)
(See NEGATIVE.)
ROLLOUT RVR(See VISIBILITY.)
ROUTE- A defined path, consisting of one or more
courses in a horizontal plane, which aircraft traverse
over the surface of the earth.
(See AIRWAY.)
(See JET ROUTE.)
(See PUBLISHED ROUTE.)
(See UNPUBLISHED ROUTE.)
ROUTE ACTION NOTIFICATION- URET notifi‐
cation that a PAR/PDR/PDAR has been applied to the
flight plan.
(See ATC PREFERRED ROUTE
NOTIFICATION.)
(See USER REQUEST EVALUATION TOOL.)
ROUTE SEGMENT- As used in Air Traffic Control,
a part of a route that can be defined by two
navigational fixes, two NAVAIDs, or a fix and a
NAVAID.
(See FIX.)
(See ROUTE.)
(See ICAO term ROUTE SEGMENT.)
ROUTE SEGMENT - A portion of a route to
be flown, as defined by two consecutive significant
points specified in a flight plan.
RSA(See RUNWAY SAFETY AREA.)
RTR(See REMOTE TRANSMITTER/RECEIVER.)
RUNWAY- A defined rectangular area on a land
airport prepared for the landing and takeoff run of
aircraft along its length. Runways are normally
numbered in relation to their magnetic direction
rounded off to the nearest 10 degrees; e.g., Runway
1, Runway 25.
(See PARALLEL RUNWAYS.)
(See ICAO term RUNWAY.)
RUNWAY - A defined rectangular area on a
land aerodrome prepared for the landing and take‐off
of aircraft.
RUNWAY CENTERLINE LIGHTING(See AIRPORT LIGHTING.)
RUNWAY CONDITION READING- Numerical
decelerometer readings relayed by air traffic
controllers at USAF and certain civil bases for use by
the pilot in determining runway braking action.
These readings are routinely relayed only to USAF
and Air National Guard Aircraft.
(See BRAKING ACTION.)
RUNWAY END IDENTIFIER LIGHTS(See AIRPORT LIGHTING.)
RUNWAY GRADIENT- The average slope, mea‐
sured in percent, between two ends or points on a
runway. Runway gradient is depicted on Government
aerodrome sketches when total runway gradient
exceeds 0.3%.
RUNWAY HEADING- The magnetic direction that
corresponds with the runway centerline extended, not
the painted runway number. When cleared to “fly or
maintain runway heading,” pilots are expected to fly
or maintain the heading that corresponds with the
extended centerline of the departure runway. Drift
correction shall not be applied; e.g., Runway 4, actual
Pilot/Controller Glossary 2/14/08
PCG R-7
magnetic heading of the runway centerline 044, fly
044.
RUNWAY IN USE/ACTIVE RUNWAY/DUTY
RUNWAY- Any runway or runways currently being
used for takeoff or landing. When multiple runways
are used, they are all considered active runways. In
the metering sense, a selectable adapted item which
specifies the landing runway configuration or
direction of traffic flow. The adapted optimum flight
plan from each transition fix to the vertex is
determined by the runway configuration for arrival
metering processing purposes.
RUNWAY LIGHTS(See AIRPORT LIGHTING.)
RUNWAY MARKINGS(See AIRPORT MARKING AIDS.)
RUNWAY OVERRUN- In military aviation exclu‐
sively, a stabilized or paved area beyond the end of a
runway, of the same width as the runway plus
shoulders, centered on the extended runway
centerline.
RUNWAY PROFILE DESCENT- An instrument
flight rules (IFR) air traffic control arrival procedure
to a runway published for pilot use in graphic and/or
textual form and may be associated with a STAR.
Runway Profile Descents provide routing and may
depict crossing altitudes, speed restrictions, and
headings to be flown from the en route structure to the
point where the pilot will receive clearance for and
execute an instrument approach procedure. A
Runway Profile Descent may apply to more than one
runway if so stated on the chart.
(Refer to AIM.)
RUNWAY SAFETY AREA- A defined surface
surrounding the runway prepared, or suitable, for
reducing the risk of damage to airplanes in the event
of an undershoot, overshoot, or excursion from the
runway. The dimensions of the RSA vary and can be
determined by using the criteria contained within
AC 150/5300‐13, Airport Design, Chapter 3.
Figure3-1 in AC 150/5300‐13 depicts the RSA. The
design standards dictate that the RSA shall be:
a. Cleared, graded, and have no potentially
hazardous ruts, humps, depressions, or other surface
variations;
b. Drained by grading or storm sewers to prevent
water accumulation;
c. Capable, under dry conditions, of supporting
snow rem oval equipment, aircraft rescue and
firefighting equipment, and the occasional passage of
aircraft without causing structural damage to the
aircraft; and,
d. Free of objects, except for objects that need to
be located in the runway safety area because of their
function. These objects shall be constructed on low
impact resistant supports (frangible mounted struc‐
tures) to the lowest practical height with the frangible
point no higher than 3 inches above grade.
(Refer to AC 150/5300‐13, Airport Design,
Chapter 3.)
RUNWAY TRANSITIONa. Conventional STARs/SIDs. The portion of a
STAR/SID that serves a particular runway or
runways at an airport.
b. RNAV STARs/SIDs. Defines a path(s) from
the common route to the final point(s) on a STAR. For
a SID, the common route that serves a particular
runway or runways at an airport.
RUNWAY USE PROGRAM- A noise abatement
runway selection plan designed to enhance noise
abatement efforts with regard to airport communities
for arriving and departing aircraft. These plans are
developed into runway use programs and apply to all
turbojet aircraft 12,500 pounds or heavier; turbojet
aircraft less than 12,500 pounds are included only if
the airport proprietor determines that the aircraft
creates a noise problem. Runway use programs are
coordinated with FAA offices, and safety criteria
used in these programs are developed by the Office of
Flight Operations. Runway use program s are
administered by the Air Traffic Service as “Formal”
or “Informal” programs.
a. Formal Runway Use Program- An approved
noise abatement program which is defined and
acknowledged in a Letter of Understanding between
Flight Operations, Air Traffic Service, the airport
proprietor, and the users. Once established, participa‐
tion in the program is mandatory for aircraft operators
and pilots as provided for in 14 CFR Section 91.129.
b. Informal Runway Use Program- An approved
noise abatement program which does not require a
Letter of Understanding, and participation in the
program is voluntary for aircraft operators/pilots.
Pilot/Controller Glossary 2/14/08
PCG R-8
RUNWAY VISIBILITY VALUE(See VISIBILITY.)
RUNWAY VISUAL RANGE(See VISIBILITY.)
Pilot/Controller Glossary 2/14/08
PCG S-1
S
SAA(See SPECIAL ACTIVITY AIRSPACE.)
SAFETY ALERT- A safety alert issued by ATC to
aircraft under their control if ATC is aware the aircraft
is at an altitude which, in the controller's judgment,
places the aircraft in unsafe proximity to terrain,
obstructions, or other aircraft. The controller may
discontinue the issuance of further alerts if the pilot
advises he/she is taking action to correct the situation
or has the other aircraft in sight.
a. Terrain/Obstruction Alert- A safety alert issued
by ATC to aircraft under their control if ATC is aware
the aircraft is at an altitude which, in the controller's
judgment, places the aircraft in unsafe proximity to
terrain/obstructions; e.g., “Low Altitude Alert, check
your altitude immediately.”
b. Aircraft Conflict Alert- A safety alert issued by
ATC to aircraft under their control if ATC is aware of
an aircraft that is not under their control at an altitude
which, in the controller's judgment, places both
aircraft in unsafe proximity to each other. With the
alert, ATC will offer the pilot an alternate course of
action when feasible; e.g., “Traffic Alert, advise you
turn right heading zero niner zero or climb to eight
thousand immediately.”
Note:The issuance of a safety alert is contingent
upon the capability of the controller to have an
awareness of an unsafe condition. The course of
action provided will be predicated on other traffic
under ATC control. Once the alert is issued, it is
solely the pilot's prerogative to determine what
course of action, if any, he/she will take.
SAFETY LOGIC SYSTEM- A software enhance‐
ment to ASDE-3, ASDE-X, and ASDE-3X, that
predicts the path of aircraft landing and/or departing,
and/or vehicular movements on runways. Visual and
aural alarms are activated when the safety logic
projects a potential collision. The Airport Movement
Area Safety System (AMASS) is a safety logic
system enhancement to the ASDE-3. The Safety
Logic System for ASDE-X and ASDE-3X is an
integral part of the software program.
SAFETY LOGIC SYSTEM ALERTSa. ALERT- An actual situation involving two real
safety logic tracks (aircraft/aircraft, aircraft/vehicle,
or aircraft/other tangible object) that safety logic has
predicted will result in an imminent collision, based
upon the current set of Safety Logic parameters.
b. FALSE ALERT1. Alerts generated by one or more false
surface-radar targets that the system has interpreted
as real tracks and placed into safety logic.
2. Alerts in which the safety logic software did
not perform correctly, based upon the design
specifications and the current set of Safety Logic
parameters.
c. NUISANCE ALERT- An alert in which one or
more of the following is true:
1. The alert is generated by a known situation
that is not considered an unsafe operation, such as
LAHSO or other approved operations.
2. The alert is generated by inaccurate secon‐
dary radar data received by the Safety Logic System.
3. The alert is generated by surface radar targets
caused by moderate or greater precipitation.
4. One or more of the aircraft involved in the
alert is not intending to use a runway (i.e., helicopter,
pipeline patrol, non-Mode C overflight, etc.).
d. VALID NON-ALERT- A situation in which
the safety logic software correctly determines that an
alert is not required, based upon the design
specifications and the current set of Safety Logic
parameters.
e. INVALID NON-ALERT- A situation in which
the safety logic software did not issue an alert when
an alert was required, based upon the design
specifications.
SAIL BACK- A maneuver during high wind
conditions (usually with power off) where float plane
movement is controlled by water rudders/opening
and closing cabin doors.
SAME DIRECTION AIRCRAFT- Aircraft are
operating in the same direction when:
a. They are following the same track in the same
direction; or
b. Their tracks are parallel and the aircraft are
flying in the same direction; or
c. Their tracks intersect at an angle of less than 45
degrees.
Pilot/Controller Glossary 2/14/08
PCG S-2
SAR(See SEARCH AND RESCUE.)
SAY AGAIN- Used to request a repeat of the last
transmission. Usually specifies transmission or
portion thereof not understood or received; e.g., “Say
again all after ABRAM VOR.”
SAY ALTITUDE- Used by ATC to ascertain an
aircraft's specific altitude/flight level. When the
aircraft is climbing or descending, the pilot should
state the indicated altitude rounded to the nearest 100
feet.
SAY HEADING- Used by ATC to request an aircraft
heading. The pilot should state the actual heading of
the aircraft.
SCHEDULED TIME OF ARRIVAL (STA)- A STA
is the desired time that an aircraft should cross a
certain point (landing or metering fix). It takes other
traffic and airspace configuration into account. A
STA time shows the results of the TMA scheduler
that has calculated an arrival time according to
parameters such as optimized spacing, aircraft
performance, and weather.
SDF(See SIMPLIFIED DIRECTIONAL FACILITY.)
SEA LANE- A designated portion of water outlined
by visual surface markers for and intended to be used
by aircraft designed to operate on water.
SEARCH AND RESCUE- A service which seeks
missing aircraft and assists those found to be in need
of assistance. It is a cooperative effort using the
facilities and services of available Federal, state and
local agencies. The U.S. Coast Guard is responsible
for coordination of search and rescue for the Maritime
Region, and the U.S. Air Force is responsible for
search and rescue for the Inland Region. Information
pertinent to search and rescue should be passed
through any air traffic facility or be transmitted
directly to the Rescue Coordination Center by
telephone.
(See FLIGHT SERVICE STATION.)
(See RESCUE COORDINATION CENTER.)
(Refer to AIM.)
SEARCH AND RESCUE FACILITY- A facility
responsible for maintaining and operating a search
and rescue (SAR) service to render aid to persons and
property in distress. It is any SAR unit, station, NET,
or other operational activity which can be usefully
employed during an SAR Mission; e.g., a Civil Air
Patrol Wing, or a Coast Guard Station.
(See SEARCH AND RESCUE.)
SECONDARY RADAR TARGET- A target derived
from a transponder return presented on a radar
display.
SECTIONAL AERONAUTICAL CHARTS(See AERONAUTICAL CHART.)
SECTOR LIST DROP INTERVAL- A parameter
number of minutes after the meter fix time when
arrival aircraft will be deleted from the arrival sector
list.
SEE AND AVOID- When weather conditions
permit, pilots operating IFR or VFR are required to
observe and maneuver to avoid other aircraft.
Right‐of‐way rules are contained in 14 CFR Part 91.
SEGMENTED CIR CLE- A system of visual
indicators designed to provide traffic pattern
information at airports without operating control
towers.
(Refer to AIM.)
SEGMENTS OF AN INSTRUMENT APPROACH
PROCEDURE- An instrument approach procedure
may have as many as four separate segm ents
depending on how the approach procedure is
structured.
a. Initial Approach- The segment between the
initial approach fix and the intermediate fix or the
point where the aircraft is established on the
intermediate course or final approach course.
(See ICAO term INITIAL APPROACH
SEGMENT.)
b. Intermediate Approach- The segment between
the intermediate fix or point and the final approach
fix.
(See ICAO term INTERMEDIATE APPROACH
SEGMENT.)
c. Final Approach- The segment between the final
approach fix or point and the runway, airport, or
missed approach point.
(See ICAO term FINAL APPROACH SEGMENT.)
d. Missed Approach- The segment between the
missed approach point or the point of arrival at
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PCG S-3
decision height and the missed approach fix at the
prescribed altitude.
(Refer to 14 CFR Part 97.)
(See ICAO term MISSED APPROACH
PROCEDURE.)
SEPARATION- In air traffic control, the spacing of
aircraft to achieve their safe and orderly movement in
flight and while landing and taking off.
(See SEPARATION MINIMA.)
(See ICAO term SEPARATION.)
SEPARATION - Spacing between aircraft,
levels or tracks.
SEPARATION MINIMA- The minimum longitudi‐
nal, lateral, or vertical distances by which aircraft are
spaced through the application of air traffic control
procedures.
(See SEPARATION.)
SERVICE- A generic term that designates functions
or assistance available from or rendered by air traffic
control. For example, Class C service would denote
the ATC services provided within a Class C airspace
area.
SEVERE WEATHER AVOIDANCE PLAN- An
approved plan to minimize the affect of severe
weather on traffic flows in impacted terminal and/or
ARTCC areas. SWAP is normally implemented to
provide the least disruption to the ATC system when
flight through portions of airspace is difficult or
impossible due to severe weather.
SEVERE WEATHER FORECAST ALERTS-
Preliminary messages issued in order to alert users
that a Severe Weather Watch Bulletin (WW) is being
issued. These messages define areas of possible
severe thunderstorms or tornado activity. The
messages are unscheduled and issued as required by
the Storm Prediction Center (SPC) at Norman,
Oklahoma.
(See AIRMET.)
(See CONVECTIVE SIGMET.)
(See CWA.)
(See SIGMET.)
SFA(See SINGLE FREQUENCY APPROACH.)
SFO(See SIMULATED FLAMEOUT.)
SHF(See SUPER HIGH FREQUENCY.)
SHORT RANGE CLEARANCE- A clearance
issued to a departing IFR flight which authorizes IFR
flight to a specific fix short of the destination while
air traffic control facilities are coordinating and
obtaining the complete clearance.
SHORT TAKEOFF AND LANDING AIRCRAFT-
An aircraft which, at some weight within its approved
operating weight, is capable of operating from a
STOL runway in compliance with the applicable
STOL characteristics, airworthiness, operations,
noise, and pollution standards.
(See VERTICAL TAKEOFF AND LANDING
AIRCRAFT.)
SIAP(See STANDARD INSTRUMENT APPROACH
PROCEDURE.)
SID(See STANDARD INSTRUMENT DEPARTURE.)
SIDESTEP MANEUVER- A visual maneuver
accomplished by a pilot at the completion of an
instrument approach to permit a straight‐in landing
on a parallel runway not more than 1,200 feet to either
side of the runway to which the instrument approach
was conducted.
(Refer to AIM.)
SIGMET- A weather advisory issued concerning
weather significant to the safety of all aircraft.
SIGMET advisories cover severe and extreme
turbulence, severe icing, and widespread dust or
sandstorms that reduce visibility to less than 3 miles.
(See AIRMET.)
(See AWW.)
(See CONVECTIVE SIGMET.)
(See CWA.)
(See ICAO term SIGMET INFORMATION.)
(Refer to AIM.)
SIGMET INFORMATION - Information
issued by a meteorological watch office concerning
the occurrence or expected occurrence of specified
en‐route weather phenomena which may affect the
safety of aircraft operations.
SIGNIFICANT METEOROLOGICAL INFOR‐
MATION(See SIGMET.)
SIGNIFICANT POINT- A point, whether a named
intersection, a NAVAID, a fix derived from a
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NAVAID(s), or geographical coordinate expressed in
degrees of latitude and longitude, which is
established for the purpose of providing separation,
as a reporting point, or to delineate a route of flight.
SIMPLIFIED DIRECTIONAL FACILITY- A
NAVAID used for nonprecision instrument ap‐
proaches. The final approach course is similar to that
of an ILS localizer except that the SDF course may be
offset from the runway, generally not more than 3
degrees, and the course may be wider than the
localizer, resulting in a lower degree of accuracy.
(Refer to AIM.)
SIMULATED FLAMEOUT- A practice approach
by a jet aircraft (normally military) at idle thrust to a
runway. The approach may start at a runway (high
key) and may continue on a relatively high and wide
downwind leg with a continuous turn to final. It
terminates in landing or low approach. The purpose
of this approach is to simulate a flameout.
(See FLAMEOUT.)
SIMULTANEOUS ILS APPROACHES- An ap‐
proach system permitting simultaneous ILS/MLS
approaches to airports having parallel runways
separated by at least 4,300 feet between centerlines.
Integral parts of a total system are ILS/MLS, radar,
communications, ATC procedures, and appropriate
airborne equipment.
(See PARALLEL RUNWAYS.)
(Refer to AIM.)
SIMULTANEOUS MLS APPROACHES(See SIMULTANEOUS ILS APPROACHES.)
SINGLE DIRECTION ROUTES- Preferred IFR
Routes which are sometimes depicted on high
altitude en route charts and which are normally flown
in one direction only.
(See PREFERRED IFR ROUTES.)
(Refer to AIRPORT/FACILITY DIRECTORY.)
SINGLE FREQUENCY APPROACH- A service
provided under a letter of agreement to military
single‐piloted turbojet aircraft which permits use of
a single UHF frequency during approach for landing.
Pilots will not normally be required to change
frequency from the beginning of the approach to
touchdown except that pilots conducting an en route
descent are required to change frequency when
control is transferred from the air route traffic control
center to the terminal facility. The abbreviation
“SFA” in the DOD FLIP IFR Supplement under
“Communications” indicates this service is available
at an aerodrome.
SINGLE‐PILOTED AIRCRAFT- A military turbo‐
jet aircraft possessing one set of flight controls,
tandem cockpits, or two sets of flight controls but
operated by one pilot is considered single‐piloted by
ATC when determining the appropriate air traffic
service to be applied.
(See SINGLE FREQUENCY APPROACH.)
SKYSPOTTER- A pilot who has received special‐
ized training in observing and reporting inflight
weather phenomena.
SLASH- A radar beacon reply displayed as an
elongated target.
SLDI(See SECTOR LIST DROP INTERVAL.)
SLOT TIME(See METER FIX TIME/SLOT TIME.)
SLOW TAXI- To taxi a float plane at low power or
low RPM.
SN(See SYSTEM STRATEGIC NAVIGATION.)
SPEAK SLOWER- Used in verbal communications
as a request to reduce speech rate.
SPECIAL ACTIVITY AIRSPACE (SAA)- Any
airspace with defined dimensions within the National
Airspace System wherein limitations may be
imposed upon aircraft operations. This airspace may
be restricted areas, prohibited areas, military
operations areas, air ATC assigned airspace, and any
other designated airspace areas. The dimensions of
this airspace are programmed into URET and can be
designated as either active or inactive by screen entry.
Aircraft trajectories are constantly tested against the
dimensions of active areas and alerts issued to the
applicable sectors when violations are predicted.
(See USER REQUEST EVALUATION TOOL.)
SPECIAL EMERGENCY- A condition of air piracy
or other hostile act by a person(s) aboard an aircraft
which threatens the safety of the aircraft or its
passengers.
SPECIAL INSTRUMENT APPROACH PROCE‐
DURE(See INSTRUMENT APPROACH PROCEDURE.)
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SPECIAL USE AIRSPACE- Airspace of defined
dimensions identified by an area on the surface of the
earth wherein activities must be confined because of
their nature and/or wherein limitations may be
imposed upon aircraft operations that are not a part of
those activities. Types of special use airspace are:
a. Alert Area- Airspace which may contain a high
volume of pilot training activities or an unusual type
of aerial activity, neither of which is hazardous to
aircraft. Alert Areas are depicted on aeronautical
charts for the information of nonparticipating pilots.
All activities within an Alert Area are conducted in
accordance with Federal Aviation Regulations, and
pilots of participating aircraft as well as pilots
transiting the area are equally responsible for
collision avoidance.
b. Controlled Firing Area- Airspace wherein
activities are conducted under conditions so
controlled as to eliminate hazards to nonparticipating
aircraft and to ensure the safety of persons and
property on the ground.
c. Military Operations Area (MOA)- A MOA is
airspace established outside of Class A airspace area
to separate or segregate certain nonhazardous
military activities from IFR traffic and to identify for
VFR traffic where these activities are conducted.
(Refer to AIM.)
d. Prohibited Area- Airspace designated under
14 CFR Part 73 within which no person may operate
an aircraft without the permission of the using
agency.
(Refer to AIM.)
(Refer to En Route Charts.)
e. Restricted Area- Airspace designated under
14 CFR Part 73, within which the flight of aircraft,
while not wholly prohibited, is subject to restriction.
Most restricted areas are designated joint use and
IFR/VFR operations in the area may be authorized by
the controlling ATC facility when it is not being
utilized by the using agency. Restricted areas are
depicted on en route charts. Where joint use is
authorized, the name of the ATC controlling facility
is also shown.
(Refer to 14 CFR Part 73.)
(Refer to AIM.)
f. Warning Area- A warning area is airspace of
defined dimensions extending from 3 nautical miles
outward from the coast of the United States, that
contains activity that may be hazardous to
nonparticipating aircraft. The purpose of such
warning area is to warn nonparticipating pilots of the
potential danger. A warning area may be located over
domestic or international waters or both.
SPECIAL VFR CONDITIONS- Meteorological
conditions that are less than those required for basic
VFR flight in Class B, C, D, or E surface areas and
in which some aircraft are permitted flight under
visual flight rules.
(See SPECIAL VFR OPERATIONS.)
(Refer to 14 CFR Part 91.)
SPECIAL VFR FLIGHT - A VFR flight
cleared by air traffic control to operate within Class
B, C, D, and E surface areas in metrological
conditions below VMC.
SPECIAL VFR OPERATIONS- Aircraft operating
in accordance with clearances within Class B, C, D,
and E surface areas in weather conditions less than the
basic VFR weather minima. Such operations must be
requested by the pilot and approved by ATC.
(See SPECIAL VFR CONDITIONS.)
(See ICAO term SPECIAL VFR FLIGHT.)
SPEED(See AIRSPEED.)
(See GROUND SPEED.)
SPEED ADJUSTMENT- An ATC procedure used to
request pilots to adjust aircraft speed to a specific
value for the purpose of providing desired spacing.
Pilots are expected to maintain a speed of plus or
minus 10 knots or 0.02 Mach number of the specified
speed. Examples of speed adjustments are:
a. “Increase/reduce speed to Mach point (num‐
ber.)”
b. “Increase/reduce speed to (speed in knots)” or
“Increase/reduce speed (number of knots) knots.”
SPEED BRAKES- Moveable aerodynamic devices
on aircraft that reduce airspeed during descent and
landing.
SPEED SEGMENTS- Portions of the arrival route
between the transition point and the vertex along the
optimum flight path for which speeds and altitudes
are specified. There is one set of arrival speed
segments adapted from each transition point to each
vertex. Each set may contain up to six segments.
SQUAWK (Mode, Code, Function)- Activate
specific modes/codes/functions on the aircraft
transponder; e.g., “Squawk three/alpha, two one zero
five, low.”
(See TRANSPONDER.)
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PCG S-6
STA(See SCHEDULED TIME OF ARRIVAL.)
STAGING/QUEUING- The placement, integration,
and segregation of departure aircraft in designated
movement areas of an airport by departure fix, EDCT,
and/or restriction.
STAND BY- Means the controller or pilot must
pause for a few seconds, usually to attend to other
duties of a higher priority. Also means to wait as in
“stand by for clearance. ” The caller should
reestablish contact if a delay is lengthy. “Stand by” is
not an approval or denial.
STANDARD INSTRUMENT APPROACH PRO‐
CEDURE (SIAP)-
(See INSTRUMENT APPROACH PROCEDURE.)
STANDARD INSTRUMENT DEPARTURE (SID)-
A preplanned instrument flight rule (IFR) air traffic
control (ATC) departure procedure printed for
pilot/controller use in graphic form to provide
obstacle clearance and a transition from the terminal
area to the appropriate en route structure. SIDs are
primarily designed for system enhancement to
expedite traffic flow and to reduce pilot/controller
workload. ATC clearance must always be received
prior to flying a SID.
(See IFR TAKEOFF MINIMUMS AND
DEPARTURE PROCEDURES.)
(See OBSTACLE DEPARTURE PROCEDURE.)
(Refer to AIM.)
STANDARD RATE TURN- A turn of three degrees
per second.
STANDARD TERMINAL ARRIVAL- A pre‐
planned instrument flight rule (IFR) air traffic control
arrival procedure published for pilot use in graphic
and/or textual form. STARs provide transition from
the en route structure to an outer fix or an instrument
approach fix/arrival waypoint in the terminal area.
STANDARD TERMINAL ARRIVAL CHARTS(See AERONAUTICAL CHART.)
STANDARD TERMINAL AUTOMATION RE‐
PLACEMENT SYSTEM (STARS)-
(See DTAS.)
STAR(See STANDARD TERMINAL ARRIVAL.)
STATE AIRCRAFT- Aircraft used in military,
customs and police service, in the exclusive service
of any government, or of any political subdivision,
thereof including the government of any state,
territory, or possession of the United States or the
District of Columbia, but not including any
government‐owned aircraft engaged in carrying
persons or property for commercial purposes.
STATIC RESTRICTIONS- Those restrictions that
are usually not subject to change, fixed, in place,
and/or published.
STATIONARY RESERVATIONS- Altitude reserva‐
tions which encompass activities in a fixed area.
Stationary reservations may include activities, such
as special tests of weapons systems or equipment,
certain U.S. Navy carrier, fleet, and anti‐submarine
operations, rocket, missile and drone operations, and
certain aerial refueling or similar operations.
STEP TAXI- To taxi a float plane at full power or
high RPM.
STEP TURN- A maneuver used to put a float plane
in a planing configuration prior to entering an active
sea lane for takeoff. The STEP TURN maneuver
should only be used upon pilot request.
STEPDOWN FIX- A fix permitting additional
descent within a segment of an instrument approach
procedure by identifying a point at which a
controlling obstacle has been safely overflown.
STEREO ROUTE- A routinely used route of flight
established by users and ARTCCs identified by a
coded name; e.g., ALPHA 2. These routes minimize
flight plan handling and communications.
STOL AIRCRAFT(See SHORT TAKEOFF AND LANDING
AIRCRAFT.)
STOP ALTITUDE SQUAWK- Used by ATC to
inform an aircraft to turn‐off the automatic altitude
reporting feature of its transponder. It is issued when
the verbally reported altitude varies 300 feet or more
from the automatic altitude report.
(See ALTITUDE READOUT.)
(See TRANSPONDER.)
STOP AND GO- A procedure wherein an aircraft
will land, make a complete stop on the runway, and
then commence a takeoff from that point.
(See LOW APPROACH.)
(See OPTION APPROACH.)
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STOP BURST(See STOP STREAM.)
STOP BUZZER(See STOP STREAM.)
STOP SQUAWK (Mode or Code)- Used by ATC to
tell the pilot to turn specified functions of the aircraft
transponder off.
(See STOP ALTITUDE SQUAWK.)
(See TRANSPONDER.)
STOP STREAM- Used by ATC to request a pilot to
suspend electronic attack activity.
(See JAMMING.)
STOPOVER FLIGHT PLAN- A flight plan format
which permits in a single submission the filing of a
sequence of flight plans through interim full‐stop
destinations to a final destination.
STOPWAY- An area beyond the takeoff runway no
less wide than the runway and centered upon the
extended centerline of the runway, able to support the
airplane during an aborted takeoff, without causing
structural damage to the airplane, and designated by
the airport authorities for use in decelerating the
airplane during an aborted takeoff.
STRAIGHT‐IN APPROACH IFR- An instrument
approach wherein final approach is begun without
first having executed a procedure turn, not
necessarily completed with a straight‐in landing or
made to straight‐in landing minimums.
(See LANDING MINIMUMS.)
(See STRAIGHT‐IN APPROACH VFR.)
(See STRAIGHT‐IN LANDING.)
STRAIGHT‐IN APPROACH VFR- Entry into the
traffic pattern by interception of the extended runway
centerline (final approach course) without executing
any other portion of the traffic pattern.
(See TRAFFIC PATTERN.)
STRAIGHT‐IN LANDING- A landing made on a
runway aligned within 30 of the final approach
course following completion of an instrument
approach.
(See STRAIGHT‐IN APPROACH IFR.)
STRAIGHT‐IN LANDING MINIMUMS(See LANDING MINIMUMS.)
STRAIGHT‐IN MINIMUMS(See STRAIGHT‐IN LANDING MINIMUMS.)
STRATEGIC PLANNING- Planning whereby
solutions are sought to resolve potential conflicts.
SUBSTITUTE ROUTE- A route assigned to pilots
when any part of an airway or route is unusable
because of NAVAID status. These routes consist of:
a. Substitute routes which are shown on U.S.
Government charts.
b. Routes defined by ATC as specific NAVAID
radials or courses.
c. Routes defined by ATC as direct to or between
NAVAIDs.
SUNSET AND SUNRISE- The mean solar times of
sunset and sunrise as published in the Nautical
Almanac, converted to local standard time for the
locality concerned. Within Alaska, the end of evening
civil twilight and the beginning of morning civil
twilight, as defined for each locality.
SUPER HIGH FREQUENCY- The frequency band
between 3 and 30 gigahertz (GHz). The elevation and
azimuth stations of the microwave landing system
operate from 5031 MHz to 5091 MHz in this
spectrum.
SUPPLEMENTAL WEATHER SERVICE LOCA‐
TION- Airport facilities staffed with contract
personnel who take weather observations and
provide current local weather to pilots via telephone
or radio. (All other services are provided by the parent
FSS.)
SUPPS- Refers to ICAO Document 7030 Regional
Supplementary Procedures. SUPPS contain proce‐
dures for each ICAO Region which are unique to that
Region and are not covered in the worldwide
provisions identified in the ICAO Air Navigation
Plan. Procedures contained in Chapter 8 are based in
part on those published in SUPPS.
SURFACE AREA- The airspace contained by the
lateral boundary of the Class B, C, D, or E airspace
designated for an airport that begins at the surface and
extends upward.
SURPIC- A description of surface vessels in the area
of a Search and Rescue incident including their
predicted positions and their characteristics.
(Refer to FAAO JO 7110.65, Para 10-6-4,
INFLIGHT CONTINGENCIES.)
SURVEILLANCE APPROACH- An instrument
approach wherein the air traffic controller issues
instructions, for pilot compliance, based on aircraft
Pilot/Controller Glossary 2/14/08
PCG S-8
position in relation to the final approach course
(azimuth), and the distance (range) from the end of
the runway as displayed on the controller's radar
scope. The controller will provide recommended
altitudes on final approach if requested by the pilot.
(Refer to AIM.)
SWAP(See SEVERE WEATHER AVOIDANCE PLAN.)
SWSL(See SUPPLEMENTAL WEATHER SERVICE
LOCATION.)
SYSTEM STRATEGIC NAVIGATION- Military
activity accomplished by navigating along a
preplanned route using internal aircraft systems to
maintain a desired track. This activity normally
requires a lateral route width of 10 NM and altitude
range of 1,000 feet to 6,000 feet AGL with some route
segments that permit terrain following.
Pilot/Controller Glossary 2/14/08
PCG T-1
T
TACAN(See TACTICAL AIR NAVIGATION.)
TACAN‐ONLY AIRCRAFT- An aircraft, normally
military, possessing TACAN with DME but no VOR
navigational system capability. Clearances must
specify TACAN or VORTAC fixes and approaches.
TACTICAL AIR NAVIGATION- An ultra‐high
frequency electronic rho‐theta air navigation aid
which provides suitably equipped aircraft a
continuous indication of bearing and distance to the
TACAN station.
(See VORTAC.)
(Refer to AIM.)
TAILWIND- Any wind more than 90 degrees to the
longitudinal axis of the runway. The magnetic
direction of the runway shall be used as the basis for
determining the longitudinal axis.
TAKEOFF AREA(See LANDING AREA.)
TAKE‐OFF DISTANCE AVAILABLE - The
length of the take‐off run available plus the length of
the clearway, if provided.
TAKE‐OFF RUN AVAILABLE - The length
of runway declared available and suitable for the
ground run of an aeroplane take‐off.
TARGET- The indication shown on an analog
display resulting from a primary radar return or a
radar beacon reply.
(See ASSOCIATED.)
(See DIGITAL TARGET.)
(See DIGITIZED RADAR TARGET.)
(See PRIMARY RADAR TARGET.)
(See RADAR.)
(See SECONDARY RADAR TARGET.)
(See TARGET SYMBOL.)
(See ICAO term TARGET.)
(See UNASSOCIATED.)
TARGET - In radar:
a. Generally, any discrete object which reflects or
retransmits energy back to the radar equipment.
b. Specifically, an object of radar search or
surveillance.
TARGET RESOLUTION- A process to ensure that
correlated radar targets do not touch. Target
resolution shall be applied as follows:
a. Between the edges of two primary targets or the
edges of the ASR‐9 primary target symbol.
b. Between the end of the beacon control slash and
the edge of a primary target.
c. Between the ends of two beacon control slashes.
Note 1:MANDATORY TRAFFIC ADVISORIES
AND SAFETY ALERTS SHALL BE ISSUED
WHEN THIS PROCEDURE IS USED.
Note 2:This procedure shall not be provided
utilizing mosaic radar systems.
TARGET SYMBOL- A computer‐generated indica‐
tion shown on a radar display resulting from a
primary radar return or a radar beacon reply.
TAS(See TERMINAL AUTOMATION SYSTEMS.)
TAWS(See TERRAIN AWARENESS WARNING
SYSTEM.)
TAXI- The movement of an airplane under its own
power on the surface of an airport (14 CFR
Section 135.100 ). Also, it describes the
surface movement of helicopters equipped with
wheels.
(See AIR TAXI.)
(See HOVER TAXI.)
(Refer to 14 CFR Section 135.100.)
(Refer to AIM.)
TAXI PATTERNS- Patterns established to illustrate
the desired flow of ground traffic for the different
runways or airport areas available for use.
TCAS(See TRAFFIC ALERT AND COLLISION
AVOIDANCE SYSTEM.)
TCH(See THRESHOLD CROSSING HEIGHT.)
TCLT(See TENTATIVE CALCULATED LANDING
TIME.)
TDLS(See TERMINAL DATA LINK SYSTEM.)
Pilot/Controller Glossary 2/14/08
PCG T-2
TDZE(See TOUCHDOWN ZONE ELEVATION.)
TELEPHONE INFORMATION BRIEFING SER‐
VIC E- A continuous telephone recording of
meteorological and/or aeronautical information.
(Refer to AIM.)
TENTATIVE CALCULATED LANDING TIME- A
projected time calculated for adapted vertex for each
arrival aircraft based upon runway configuration,
airport acceptance rate, airport arrival delay period,
and other metered arrival aircraft. This time is either
the VTA of the aircraft or the TCLT/ACLT of the
previous aircraft plus the AAI, whichever is later.
This time will be updated in response to an aircraft's
progress and its current relationship to other arrivals.
TERMINAL AREA- A general term used to describe
airspace in which approach control service or airport
traffic control service is provided.
TERMINAL AREA FACILITY- A facility provid‐
ing air traffic control service for arriving and
departing IFR, VFR, Special VFR, and on occasion
en route aircraft.
(See APPROACH CONTROL FACILITY.)
(See TOWER.)
TERMINAL AUTOMATION SYSTEMS (TAS)-
TAS is used to identify the numerous automated
tracking systems including ARTS IIE, ARTS IIIA,
ARTS IIIE, STARS, and MEARTS.
TERMINAL DATA LINK SYSTEM (TDLS)- A
system that provides Digital Automatic Terminal
Information Service (D-ATIS) both on a specified
radio frequency and also, for subscribers, in a text
message via data link to the cockpit or to a gate
printer. TDLS also provides Pre-departure Clear‐
ances (PDC), at selected airports, to subscribers,
through a service provider, in text to the cockpit or to
a gate printer. In addition, TDLS will emulate the
Flight Data Input/Output (FDIO) information within
the control tower.
TERMINAL RADAR SERVICE AREA- Airspace
surrounding designated airports wherein ATC
provides radar vectoring, sequencing, and separation
on a full‐time basis for all IFR and participating VFR
aircraft. The AIM contains an explanation of TRSA.
TRSAs are depicted on VFR aeronautical charts.
Pilot participation is urged but is not mandatory.
TERMINAL VFR RADAR SERVICE- A national
program instituted to extend the terminal radar
services provided instrument flight rules (IFR)
aircraft to visual flight rules (VFR) aircraft. The
program is divided into four types service referred to
as basic radar service, terminal radar service area
(TRSA) service, Class B service and Class C service.
The type of service provided at a particular location
is contained in the Airport/Facility Directory.
a. Basic Radar Service- These services are
provided for VFR aircraft by all commissioned
terminal radar facilities. Basic radar service includes
safety alerts, traffic advisories, limited radar
vectoring when requested by the pilot, and
sequencing at locations where procedures have been
established for this purpose and/or when covered by
a letter of agreement. The purpose of this service is to
adjust the flow of arriving IFR and VFR aircraft into
the traffic pattern in a safe and orderly manner and to
provide traffic advisories to departing VFR aircraft.
b. TRSA Service- This service provides, in
addition to basic radar service, sequencing of all IFR
and participating VFR aircraft to the primary airport
and separation between all participating VFR
aircraft. The purpose of this service is to provide
separation between all participating VFR aircraft and
all IFR aircraft operating within the area defined as a
TRSA.
c. Class C Service- This service provides, in
addition to basic radar service, approved separation
between IFR and VFR aircraft, and sequencing of
VFR aircraft, and sequencing of VFR arrivals to the
primary airport.
d. Class B Service- This service provides, in
addition to basic radar service, approved separation
of aircraft based on IFR, VFR, and/or weight, and
sequencing of VFR arrivals to the primary airport(s).
(See CONTROLLED AIRSPACE.)
(See TERMINAL RADAR SERVICE AREA.)
(Refer to AIM.)
(Refer to AIRPORT/FACILITY DIRECTORY.)
TERMINAL‐VERY HIGH FREQUENCY OMNI‐
DIRECTIONAL RANGE STATION- A very high
frequency terminal omnirange station located on or
near an airport and used as an approach aid.
(See NAVIGATIONAL AID.)
(See VOR.)
TERRAIN AWARENESS WARNING SYSTEM
(TAWS)- An on-board, terrain proximity alerting
Pilot/Controller Glossary 2/14/08
PCG T-3
system providing the aircrew `Low Altitude
warnings' to allow immediate pilot action.
TERRAIN FOLLOWING- The flight of a military
aircraft maintaining a constant AGL altitude above
the terrain or the highest obstruction. The altitude of
the aircraft will constantly change with the varying
terrain and/or obstruction.
TETRAHEDRON- A device normally located on
uncontrolled airports and used as a landing direction
indicator. The small end of a tetrahedron points in the
direction of landing. At controlled airports, the
tetrahedron, if installed, should be disregarded
because tower instructions supersede the indicator.
(See SEGMENTED CIRCLE.)
(Refer to AIM.)
TF(See TERRAIN FOLLOWING.)
THAT IS CORRECT- The understanding you have
is right.
360 OVERHEAD(See OVERHEAD MANEUVER.)
THRESHOLD- The beginning of that portion of the
runway usable for landing.
(See AIRPORT LIGHTING.)
(See DISPLACED THRESHOLD.)
THRESHOLD CROSSING HEIGHT- The theoreti‐
cal height above the runway threshold at which the
aircraft's glideslope antenna would be if the aircraft
maintains the trajectory established by the mean ILS
glideslope or MLS glidepath.
(See GLIDESLOPE.)
(See THRESHOLD.)
THRESHOLD LIGHTS(See AIRPORT LIGHTING.)
TIBS(See TELEPHONE INFORMATION BRIEFING
SERVICE.)
TIME GROUP- Four digits representing the hour
and minutes from the Coordinated Universal Time
(UTC) clock. FAA uses UTC for all operations. The
term “ZULU” may be used to denote UTC. The word
“local” or the time zone equivalent shall be used to
denote local when local time is given during radio and
telephone communications. When written, a time
zone designator is used to indicate local time; e.g.
“0205M” (Mountain). The local time may be based
on the 24‐hour clock system. The day begins at 0000
and ends at 2359.
TMA(See TRAFFIC MANAGEMENT ADVISOR.)
TMPA(See TRAFFIC MANAGEMENT PROGRAM
ALERT.)
TMU(See TRAFFIC MANAGEMENT UNIT.)
TODA -
(See ICAO Term TAKE‐OFF DISTANCE
AVAILABLE.)
TORA -
(See ICAO Term TAKE‐OFF RUN AVAILABLE.)
TORCHING- The burning of fuel at the end of an
exhaust pipe or stack of a reciprocating aircraft
engine, the result of an excessive richness in the fuel
air mixture.
TOTAL ESTIMATED ELAPSED TIME -
For IFR flights, the estimated time required from
take‐off to arrive over that designated point, defined
by reference to navigation aids, from which it is
intended that an instrument approach procedure will
be commenced, or, if no navigation aid is associated
with the destination aerodrome, to arrive over the
destination aerodrom e. For VFR flights, the
estimated time required from take‐off to arrive over
the destination aerodrome.
(See ICAO term ESTIMATED ELAPSED TIME.)
TOUCH‐AND‐GO- An operation by an aircraft that
lands and departs on a runway without stopping or
exiting the runway.
TOUCH‐AND‐GO LANDING(See TOUCH‐AND‐GO.)
TOUCHDOWNa. The point at which an aircraft first makes
contact with the landing surface.
b. Concerning a precision radar approach (PAR),
it is the point where the glide path intercepts the
landing surface.
(See ICAO term TOUCHDOWN.)
Pilot/Controller Glossary 2/14/08
PCG T-4
TOUCHDOWN - The point where the
nominal glide path intercepts the runway.
Note:Touchdown as defined above is only a datum
and is not necessarily the actual point at which the
aircraft will touch the runway.
TOUCHDOWN RVR(See VISIBILITY.)
TOUCHDOWN ZONE- The first 3,000 feet of the
runway beginning at the threshold. The area is used
for determination of Touchdown Zone Elevation in
the development of straight‐in landing minimums for
instrument approaches.
(See ICAO term TOUCHDOWN ZONE.)
TOUCHDOWN ZONE - The portion of a
runway, beyond the threshold, where it is intended
landing aircraft first contact the runway.
TOUCHDOWN ZONE ELEVATION- The highest
elevation in the first 3,000 feet of the landing surface.
TDZE is indicated on the instrument approach
procedure chart when straight‐in landing minimums
are authorized.
(See TOUCHDOWN ZONE.)
TOUCHDOWN ZONE LIGHTING(See AIRPORT LIGHTING.)
TOWER- A terminal facility that uses air/ground
communications, visual signaling, and other devices
to provide ATC services to aircraft operating in the
vicinity of an airport or on the movement area.
Authorizes aircraft to land or takeoff at the airport
controlled by the tower or to transit the Class D
airspace area regardless of flight plan or weather
conditions (IFR or VFR). A tower may also provide
approach control services (radar or nonradar).
(See AIRPORT TRAFFIC CONTROL SERVICE.)
(See APPROACH CONTROL FACILITY.)
(See APPROACH CONTROL SERVICE.)
(See MOVEMENT AREA.)
(See TOWER EN ROUTE CONTROL
SERVICE.)
(See ICAO term AERODROME CONTROL
TOWER.)
(Refer to AIM.)
TOWER EN ROUTE CONTROL SERVICE- The
control of IFR en route traffic within delegated
airspace between two or more adjacent approach
control facilities. This service is designed to expedite
traffic and reduce control and pilot communication
requirements.
TOWER TO TOWER(See TOWER EN ROUTE CONTROL
SERVICE.)
TPX‐42- A numeric beacon decoder equipment/
system. It is designed to be added to terminal radar
systems for beacon decoding. It provides rapid target
identification, reinforcement of the primary radar
target, and altitude information from Mode C.
(See AUTOMATED RADAR TERMINAL
SYSTEMS.)
(See TRANSPONDER.)
TRACEABLE PRESSURE STANDARD- The
facility station pressure instrument, with certifica‐
tion/calibration traceable to the National Institute of
Standards and Technology. Traceable pressure
standards may be mercurial barometers, commis‐
sioned ASOS or dual transducer AWOS, or portable
pressure standards or DASI.
TRACK- The actual flight path of an aircraft over the
surface of the earth.
(See COURSE.)
(See FLIGHT PATH.)
(See ROUTE.)
(See ICAO term TRACK.)
TRACK - The projection on the earth's
surface of the path of an aircraft, the direction of
which path at any point is usually expressed in
degrees from North (True, Magnetic, or Grid).
TRAFFICa. A term used by a controller to transfer radar
identification of an aircraft to another controller for
the purpose of coordinating separation action. Traffic
is normally issued:
1. In response to a handoff or point out,
2. In anticipation of a handoff or point out, or
3. In conjunction with a request for control of an
aircraft.
b. A term used by ATC to refer to one or more
aircraft.
TRAFFIC ADVISORIES- Advisories issued to alert
pilots to other known or observed air traffic which
may be in such proximity to the position or intended
route of flight of their aircraft to warrant their
attention. Such advisories may be based on:
a. Visual observation.
Pilot/Controller Glossary 2/14/08
PCG T-5
b. Observation of radar identified and nonidenti‐
fied aircraft targets on an ATC radar display, or
c. Verbal reports from pilots or other facilities.
Note 1:The word “traffic” followed by additional
information, if known, is used to provide such
advisories; e.g., “Traffic, 2 o'clock, one zero miles,
southbound, eight thousand.”
Note 2:Traffic advisory service will be provided to
the extent possible depending on higher priority
duties of the controller or other limitations; e.g.,
radar limitations, volume of traffic, frequency
congestion, or controller workload. Radar/
nonradar traffic advisories do not relieve the pilot
of his/her responsibility to see and avoid other
aircraft. Pilots are cautioned that there are many
times when the controller is not able to give traffic
advisories concerning all traffic in the aircraft's
proximity; in other words, when a pilot requests or
is receiving traffic advisories, he/she should not
assume that all traffic will be issued.
(Refer to AIM.)
TRAFFIC ALERT (aircraft call sign), TURN
(left/right) IMMEDIATELY, (climb/descend) AND
MAINTAIN (altitude).
(See SAFETY ALERT.)
TRAFFIC ALERT AND COLLISION AVOID‐
ANCE SYSTEM- An airborne collision avoidance
system based on radar beacon signals which operates
independent of ground‐based equipment. TCAS‐I
generates traffic advisories only. TCAS‐II generates
traffic advisories, and resolution (collision avoid‐
ance) advisories in the vertical plane.
TRAFFIC INFORMATION(See TRAFFIC ADVISORIES.)
TRAFFIC IN SIGHT- Used by pilots to inform a
controller that previously issued traffic is in sight.
(See NEGATIVE CONTACT.)
(See TRAFFIC ADVISORIES.)
TRAFFIC MANAGEMENT ADVISOR (TMA)- A
computerized tool which assists Traffic Management
Coordinators to efficiently schedule arrival traffic to
a metered airport, by calculating meter fix times and
delays then sending that information to the sector
controllers.
TRAFFIC MANAGEMENT PROGRAM ALERT-
A term used in a Notice to Airmen (NOTAM) issued
in conjunction with a special traffic management
program to alert pilots to the existence of the program
and to refer them to either the Notices to Airmen
publication or a special traffic management program
advisory message for program details. The contrac‐
tion TMPA is used in NOTAM text.
TRAFFIC MANAGEMENT UNIT- The entity in
ARTCCs and designated terminals directly involved
in the active management of facility traffic. Usually
under the direct supervision of an assistant manager
for traffic management.
TRAFFIC NO FACTOR- Indicates that the traffic
described in a previously issued traffic advisory is no
factor.
TRAFFIC NO LONGER OBSERVED- Indicates
that the traffic described in a previously issued traffic
advisory is no longer depicted on radar, but may still
be a factor.
TRAFFIC PATTERN- The traffic flow that is
prescribed for aircraft landing at, taxiing on, or taking
off from an airport. The components of a typical
traffic pattern are upwind leg, crosswind leg,
downwind leg, base leg, and final approach.
a. Upwind Leg- A flight path parallel to the
landing runway in the direction of landing.
b. Crosswind Leg- A flight path at right angles to
the landing runway off its upwind end.
c. Downwind Leg- A flight path parallel to the
landing runway in the direction opposite to landing.
The downwind leg normally extends between the
crosswind leg and the base leg.
d. Base Leg- A flight path at right angles to the
landing runway off its approach end. The base leg
normally extends from the downwind leg to the
intersection of the extended runway centerline.
e. Final Approach. A flight path in the direction of
landing along the extended runway centerline. The
final approach normally extends from the base leg to
the runway. An aircraft making a straight‐in approach
VFR is also considered to be on final approach.
(See STRAIGHT‐IN APPROACH VFR.)
(See TAXI PATTERNS.)
(See ICAO term AERODROME TRAFFIC
CIRCUIT.)
(Refer to 14 CFR Part 91.)
(Refer to AIM.)
TRAFFIC SITUATION DISPLAY (TSD)- TSD is a
computer system that receives radar track data from
all 20 CONUS ARTCCs, organizes this data into a
mosaic display, and presents it on a computer screen.
Pilot/Controller Glossary 2/14/08
PCG T-6
The display allows the traffic management coordina‐
tor multiple methods of selection and highlighting of
individual aircraft or groups of aircraft. The user has
the option of superimposing these aircraft positions
over any number of background displays. These
background options include ARTCC boundaries, any
stratum of en route sector boundaries, fixes, airways,
military and other special use airspace, airports, and
geopolitical boundaries. By using the TSD, a
coordinator can monitor any number of traffic
situations or the entire systemwide traffic flows.
TRAJECTORY- A URET representation of the path
an aircraft is predicted to fly based upon a Current
Plan or Trial Plan.
(See USER REQUEST EVALUATION TOOL.)
TRAJECTORY MODELING- The automated pro‐
cess of calculating a trajectory.
TRANSCRIBED WEATHER BROADCAST- A
continuous recording of meteorological and aeronau‐
tical information that is broadcast on L/MF and VOR
facilities for pilots. (Provided only in Alaska.)
(Refer to AIM.)
TRANSFER OF CONTROL- That action whereby
the responsibility for the separation of an aircraft is
transferred from one controller to another.
(See ICAO term TRANSFER OF CONTROL.)
TRANSFER OF CONTROL - Transfer of
responsibility for providing air traffic control service.
TRANSFERRING CONTROLLER- A controller/
facility transferring control of an aircraft to another
controller/facility.
(See ICAO term TRANSFERRING
UNIT/CONTROLLER.)
TRANSFERRING FACILITY(See TRANSFERRING CONTROLLER.)
TRANSFERRING UNIT/CONTROLLER -
Air traffic control unit/air traffic controller in the
process of transferring the responsibility for
providing air traffic control service to an aircraft to
the next air traffic control unit/air traffic controller
along the route of flight.
Note:See definition of accepting unit/controller.
TRANSITIONa. The general term that describes the change from
one phase of flight or flight condition to another; e.g.,
transition from en route flight to the approach or
transition from instrument flight to visual flight.
b. A published procedure (DP Transition) used to
connect the basic DP to one of several en route
airways/jet routes, or a published procedure (STAR
Transition) used to connect one of several en route
airways/jet routes to the basic STAR.
(Refer to DP/STAR Charts.)
TRANSITION POINT- A point at an adapted
number of miles from the vertex at which an arrival
aircraft would normally commence descent from its
en route altitude. This is the first fix adapted on the
arrival speed segments.
TRANSITION WAYPOINT- The waypoint that
defines the beginning of a runway or en route
transition on an RNAV SID or STAR.
TRANSITIONAL AIRSPACE- That portion of
controlled airspace wherein aircraft change from one
phase of flight or flight condition to another.
TRANSMISSOMETER- An apparatus used to
determine visibility by measuring the transmission of
light through the atmosphere. It is the measurement
source for determining runway visual range (RVR)
and runway visibility value (RVV).
(See VISIBILITY.)
TRANSMITTING IN THE BLIND- A transmis‐
sion from one station to other stations in
circumstances where two‐way communication
cannot be established, but where it is believed that the
called stations may be able to receive the
transmission.
TRANSPONDER- The airborne radar beacon
receiver/transmitter portion of the Air Traffic Control
Radar Beacon System (ATCRBS) which automati‐
cally receives radio signals from interrogators on the
ground, and selectively replies with a specific reply
pulse or pulse group only to those interrogations
being received on the mode to which it is set to
respond.
(See INTERROGATOR.)
(See ICAO term TRANSPONDER.)
(Refer to AIM.)
TRANSPONDER - A receiver/transmitter
which will generate a reply signal upon proper
interrogation; the interrogation and reply being on
different frequencies.
TRANSPONDER CODES(See CODES.)
Pilot/Controller Glossary 2/14/08
PCG T-7
TRIAL PLAN- A proposed amendment which
utilizes automation to analyze and display potential
conflicts along the predicted trajectory of the selected
aircraft.
TRSA(See TERMINAL RADAR SERVICE AREA.)
TSD(See TRAFFIC SITUATION DISPLAY.)
TURBOJET AIRCRAFT- An aircraft having a jet
engine in which the energy of the jet operates a
turbine which in turn operates the air compressor.
TURBOPROP AIRCRAFT- An aircraft having a jet
engine in which the energy of the jet operates a
turbine which drives the propeller.
TURN ANTICIPATION- (maneuver anticipation).
TVOR(See TERMINAL‐VERY HIGH FREQUENCY
OMNIDIRECTIONAL RANGE STATION.)
TWEB(See TRANSCRIBED WEATHER BROADCAST.)
TWO‐WAY RADIO COMMUNICATIONS FAIL‐
URE(See LOST COMMUNICATIONS.)
Pilot/Controller Glossary 2/14/08
PCG U-1
U
UDF(See DIRECTION FINDER.)
UHF(See ULTRAHIGH FREQUENCY.)
ULTRAHIGH FREQUENCY- The frequency band
between 300 and 3,000 MHz. The bank of radio
frequencies used for military air/ground voice
communications. In some instances this may go as
low as 225 MHz and still be referred to as UHF.
ULTRALIGHT VEHICLE- An aeronautical vehicle
operated for sport or recreational purposes which
does not require FAA registration, an airworthiness
certificate, nor pilot certification. They are primarily
single occupant vehicles, although some two‐place
vehicles are authorized for training purposes.
Operation of an ultralight vehicle in certain airspace
requires authorization from ATC.
(Refer to 14 CFR Part 103.)
UNABLE- Indicates inability to comply with a
specific instruction, request, or clearance.
UNASSOCIATED- A radar target that does not
display a data block with flight identification and
altitude information.
(See ASSOCIATED.)
UNDER THE HOOD- Indicates that the pilot is
using a hood to restrict visibility outside the cockpit
while simulating instrument flight. An appropriately
rated pilot is required in the other control seat while
this operation is being conducted.
(Refer to 14 CFR Part 91.)
UNFROZEN- The Scheduled Time of Arrival (STA)
tags, which are still being rescheduled by traffic
management advisor (TMA) calculations. The
aircraft will remain unfrozen until the time the
corresponding estimated time of arrival (ETA) tag
passes the preset freeze horizon for that aircraft's
stream class. At this point the automatic rescheduling
will stop, and the STA becomes “frozen.”
UNICOM- A nongovernment communication facil‐
ity which may provide airport information at certain
airports. Locations and frequencies of UNICOMs are
shown on aeronautical charts and publications.
(See AIRPORT/FACILITY DIRECTORY.)
(Refer to AIM.)
UNPUBLISHED ROUTE- A route for which no
minimum altitude is published or charted for pilot
use. It may include a direct route between NAVAIDs,
a radial, a radar vector, or a final approach course
beyond the segments of an instrument approach
procedure.
(See PUBLISHED ROUTE.)
(See ROUTE.)
UNRELIABLE (GPS/WAAS)- An advisory to
pilots indicating the expected level of service of the
GPS and/or WAAS may not be available. Pilots must
then determine the adequacy of the signal for desired
use.
UPWIND LEG(See TRAFFIC PATTERN.)
URET(See USER REQUEST EVALUATION TOOL.)
URGENCY- A condition of being concerned about
safety and of requiring timely but not immediate
assistance; a potential distress condition.
(See ICAO term URGENCY.)
URGENCY - A condition concerning the
safety of an aircraft or other vehicle, or of person on
board or in sight, but which does not require
immediate assistance.
USAFIB(See ARMY AVIATION FLIGHT INFORMATION
BULLETIN.)
USER REQUEST EVALUATION TOOL (URET)-
User Request Evaluation Tool is an automated tool
provided at each Radar Associate position in selected
En Route facilities. This tool utilizes flight and radar
data to determine present and future trajectories for
all active and proposal aircraft and provides
enhanced, automated flight data management.
UVDF(See DIRECTION FINDER.)
Pilot/Controller Glossary 2/14/08
PCG V-1
V
VASI(See VISUAL APPROACH SLOPE INDICATOR.)
VCOA(See VISUAL CLIMB OVER AIRPORT.)
VDF(See DIRECTION FINDER.)
VDP(See VISUAL DESCENT POINT.)
VECTOR- A heading issued to an aircraft to provide
navigational guidance by radar.
(See ICAO term RADAR VECTORING.)
VERIFY- Request confirmation of information;
e.g., “verify assigned altitude.”
VERIFY SPECIFIC DIRECTION OF TAKEOFF
(OR TURNS AFTER TAKEOFF)- Used by ATC to
ascertain an aircraft's direction of takeoff and/or
direction of turn after takeoff. It is normally used for
IFR departures from an airport not having a control
tower. When direct communication with the pilot is
not possible, the request and information may be
relayed through an FSS, dispatcher, or by other
means.
(See IFR TAKEOFF MINIMUMS AND
DEPARTURE PROCEDURES.)
VERTEX- The last fix adapted on the arrival speed
segments. Normally, it will be the outer marker of the
runway in use. However, it may be the actual
threshold or other suitable common point on the
approach path for the particular runway configura‐
tion.
VERTEX TIME OF ARRIVAL- A calculated time of
aircraft arrival over the adapted vertex for the runway
configuration in use. The time is calculated via the
optimum flight path using adapted speed segments.
VERTICAL NAVIGATION (VNAV)– A function of
area navigation (RNAV) equipment which calculates,
displays, and provides vertical guidance to a profile
or path.
VERTICAL SEPARATION- Separation established
by assignment of different altitudes or flight levels.
(See SEPARATION.)
(See ICAO term VERTICAL SEPARATION.)
VERTICAL SEPARATION - Separation
between aircraft expressed in units of vertical
distance.
VERTICAL TAKEOFF AND LANDING AIR‐
CRAFT- Aircraft capable of vertical climbs and/or
descents and of using very short runways or small
areas for takeoff and landings. These aircraft include,
but are not limited to, helicopters.
(See SHORT TAKEOFF AND LANDING
AIRCRAFT.)
VERY HIGH FREQUENCY- The frequency band
between 30 and 300 MHz. Portions of this band, 108
to 118 MHz, are used for certain NAVAIDs; 118 to
136 MHz are used for civil air/ground voice
communications. Other frequencies in this band are
used for purposes not related to air traffic control.
VERY HIGH FREQUENCY OMNIDIRECTION‐
AL RANGE STATION(See VOR.)
VERY LOW FREQUENCY- The frequency band
between 3 and 30 kHz.
VFR(See VISUAL FLIGHT RULES.)
VFR AIRCRAFT- An aircraft conducting flight in
accordance with visual flight rules.
(See VISUAL FLIGHT RULES.)
VFR CONDITIONS- Weather conditions equal to
or better than the minimum for flight under visual
flight rules. The term may be used as an ATC
clearance/instruction only when:
a. An IFR aircraft requests a climb/descent in
VFR conditions.
b. The clearance will result in noise abatement
benefits where part of the IFR departure route does
not conform to an FAA approved noise abatement
route or altitude.
c. A pilot has requested a practice instrument
approach and is not on an IFR flight plan.
Note:All pilots receiving this authorization must
comply with the VFR visibility and distance from
cloud criteria in 14 CFR Part 91. Use of the term
does not relieve controllers of their responsibility to
separate aircraft in Class B and Class C airspace
or TRSAs as required by FAAO JO 7110.65. When
Pilot/Controller Glossary 2/14/08
PCG V-2
used as an ATC clearance/instruction, the term
may be abbreviated “VFR;” e.g., “MAINTAIN
VFR,” “CLIMB/DESCEND VFR,” etc.
VFR FLIGHT(See VFR AIRCRAFT.)
VFR MILITARY TRAINING ROUTES- Routes
used by the Department of Defense and associated
Reserve and Air Guard units for the purpose of
conducting low‐altitude navigation and tactical
training under VFR below 10,000 feet MSL at
airspeeds in excess of 250 knots IAS.
VFR NOT RECOMMENDED- An advisory
provided by a flight service station to a pilot during
a preflight or inflight weather briefing that flight
under visual flight rules is not recommended. To be
given when the current and/or forecast weather
conditions are at or below VFR minimums. It does
not abrogate the pilot's authority to make his/her own
decision.
VFR‐ON‐TOP- ATC authorization for an IFR
aircraft to operate in VFR conditions at any
appropriate VFR altitude (as specified in 14 CFR and
as restricted by ATC). A pilot receiving this
authorization must comply with the VFR visibility,
distance from cloud criteria, and the minimum IFR
altitudes specified in 14 CFR Part 91. The use of this
term does not relieve controllers of their responsibil‐
ity to separate aircraft in Class B and Class C airspace
or TRSAs as required by FAAO JO 7110.65.
VFR TERMINAL AREA CHARTS(See AERONAUTICAL CHART.)
VFR WAYPOINT(See WAYPOINT.)
VHF(See VERY HIGH FREQUENCY.)
VHF OMNIDIRECTIONAL RANGE/TACTICAL
AIR NAVIGATION(See VORTAC.)
VIDEO MAP- An electronically displayed map on
the radar display that may depict data such as airports,
heliports, runway centerline extensions, hospital
emergency landing areas, NAVAIDs and fixes,
reporting points, airway/route centerlines, bound‐
aries, handoff points, special use tracks, obstructions,
prominent geographic features, map alignment
indicators, range accuracy marks, minimum vector‐
ing altitudes.
VIS IBILITY- The ability, as determ ined by
atmospheric conditions and expressed in units of
distance, to see and identify prominent unlighted
objects by day and prominent lighted objects by
night. Visibility is reported as statute miles, hundreds
of feet or meters.
(Refer to 14 CFR Part 91.)
(Refer to AIM.)
a. Flight Visibility- The average forward horizon‐
tal distance, from the cockpit of an aircraft in flight,
at which prominent unlighted objects may be seen
and identified by day and prominent lighted objects
may be seen and identified by night.
b. Ground Visibility- Prevailing horizontal visi‐
bility near the earth's surface as reported by the
United States National Weather Service or an
accredited observer.
c. Prevailing Visibility- The greatest horizontal
visibility equaled or exceeded throughout at least half
the horizon circle which need not necessarily be
continuous.
d. Runway Visibility Value (RVV)- The visibility
determined for a particular runway by a transmis‐
someter. A meter provides a continuous indication of
the visibility (reported in miles or fractions of miles)
for the runway. RVV is used in lieu of prevailing
visibility in determining minimums for a particular
runway.
e. Runway Visual Range (RVR)- An instrumen‐
tally derived value, based on standard calibrations,
that represents the horizontal distance a pilot will see
down the runway from the approach end. It is based
on the sighting of either high intensity runway lights
or on the visual contrast of other targets whichever
yields the greater visual range. RVR, in contrast to
prevailing or runway visibility, is based on what a
pilot in a moving aircraft should see looking down the
runway. RVR is horizontal visual range, not slant
visual range. It is based on the measurement of a
transmissometer made near the touchdown point of
the instrument runway and is reported in hundreds of
feet. RVR is used in lieu of RVV and/or prevailing
visibility in determining minimums for a particular
runway.
1. Touchdown RVR- The RVR visibility
readout values obtained from RVR equipment
serving the runway touchdown zone.
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2. Mid‐RVR- The RVR readout values obtained
from RVR equipment located midfield of the runway.
3. Rollout RVR- The RVR readout values
obtained from RVR equipment located nearest the
rollout end of the runway.
(See ICAO term FLIGHT VISIBILITY.)
(See ICAO term GROUND VISIBILITY.)
(See ICAO term RUNWAY VISUAL RANGE.)
(See ICAO term VISIBILITY.)
VISIBILITY - The ability, as determined by
atmospheric conditions and expressed in units of
distance, to see and identify prominent unlighted
objects by day and prominent lighted objects by
night.
a. Flight Visibility-The visibility forward from
the cockpit of an aircraft in flight.
b. Ground Visibility-The visibility at an aero‐
drome as reported by an accredited observer.
c. Runway Visual Range -The range over
which the pilot of an aircraft on the centerline of a
runway can see the runway surface markings or the
lights delineating the runway or identifying its
centerline.
VISUAL APPROACH- An approach conducted on
an instrument flight rules (IFR) flight plan which
authorizes the pilot to proceed visually and clear of
clouds to the airport. The pilot must, at all times, have
either the airport or the preceding aircraft in sight.
This approach must be authorized and under the
control of the appropriate air traffic control facility.
Reported weather at the airport must be ceiling at or
above 1,000 feet and visibility of 3 miles or greater.
(See ICAO term VISUAL APPROACH.)
VISUAL APPROACH - An approach by an
IFR flight when either part or all of an instrument
approach procedure is not completed and the
approach is executed in visual reference to terrain.
VISUAL APPROACH SLOPE INDICATOR(See AIRPORT LIGHTING.)
VISUAL CLIMB OVER AIRPORT (VCOA)- A
departure option for an IFR aircraft, operating in
visual meteorological conditions equal to or greater
than the specified visibility and ceiling, to visually
conduct climbing turns over the airport to the
published “climb-to” altitude from which to proceed
with the instrument portion of the departure. VCOA
procedures are developed to avoid obstacles greater
than 3 statute miles from the departure end of the
runway as an alternative to complying with climb
gradients greater than 200 feet per nautical mile.
These procedures are published in the `Take-Off
Minimums and (Obstacle) Departure Procedures'
section of the Terminal Procedures Publications.
(See AIM.)
VISUAL DESCENT POINT- A defined point on the
final approach course of a nonprecision straight‐in
approach procedure from which normal descent from
the MDA to the runway touchdown point may be
commenced, provided the approach threshold of that
runway, or approach lights, or other markings
identifiable with the approach end of that runway are
clearly visible to the pilot.
VISUAL FLIGHT RULES- Rules that govern the
procedures for conducting flight under visual
conditions. The term “VFR” is also used in the
United States to indicate weather conditions that are
equal to or greater than minimum VFR requirements.
In addition, it is used by pilots and controllers to
indicate type of flight plan.
(See INSTRUMENT FLIGHT RULES.)
(See INSTRUMENT METEOROLOGICAL
CONDITIONS.)
(See VISUAL METEOROLOGICAL
CONDITIONS.)
(Refer to 14 CFR Part 91.)
(Refer to AIM.)
VISUAL HOLDING- The holding of aircraft at
selected, prominent geographical fixes which can be
easily recognized from the air.
(See HOLDING FIX.)
VISUAL METEOROLOGICAL CONDITIONS-
Meteorological conditions expressed in terms of
visibility, distance from cloud, and ceiling equal to or
better than specified minima.
(See INSTRUMENT FLIGHT RULES.)
(See INSTRUMENT METEOROLOGICAL
CONDITIONS.)
(See VISUAL FLIGHT RULES.)
VISUAL SEPARATION- A means employed by
ATC to separate aircraft in terminal areas and en route
airspace in the NAS. There are two ways to effect this
separation:
a. The tower controller sees the aircraft involved
and issues instructions, as necessary, to ensure that
the aircraft avoid each other.
b. A pilot sees the other aircraft involved and upon
instructions from the controller provides his/her own
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separation by maneuvering his/her aircraft as
necessary to avoid it. This may involve following
another aircraft or keeping it in sight until it is no
longer a factor.
(See SEE AND AVOID.)
(Refer to 14 CFR Part 91.)
VLF(See VERY LOW FREQUENCY.)
VMC(See VISUAL METEOROLOGICAL
CONDITIONS.)
VOICE SWITCHING AND CONTROL SYSTEM-
The VSCS is a computer controlled switching system
that provides air traffic controllers with all voice
circuits (air to ground and ground to ground)
necessary for air traffic control.
(See VOICE SWITCHING AND CONTROL
SYSTEM.)
(Refer to AIM.)
VOR- A ground‐based electronic navigation aid
transmitting very high frequency navigation signals,
360 degrees in azimuth, oriented from magnetic
north. Used as the basis for navigation in the National
Airspace System. The VOR periodically identifies
itself by Morse Code and may have an additional
voice identification feature. Voice features may be
used by ATC or FSS for transmitting instructions/
information to pilots.
(See NAVIGATIONAL AID.)
(Refer to AIM.)
VOR TEST SIGNAL(See VOT.)
VORTAC- A navigation aid providing VOR
azimuth, TACAN azimuth, and TACAN distance
measuring equipment (DME) at one site.
(See DISTANCE MEASURING EQUIPMENT.)
(See NAVIGATIONAL AID.)
(See TACAN.)
(See VOR.)
(Refer to AIM.)
VORTICES- Circular patterns of air created by the
movem ent of an airfoil through the air when
generating lift. As an airfoil moves through the
atmosphere in sustained flight, an area of area of low
pressure is created above it. The air flowing from the
high pressure area to the low pressure area around and
about the tips of the airfoil tends to roll up into two
rapidly rotating vortices, cylindrical in shape. These
vortices are the most predominant parts of aircraft
wake turbulence and their rotational force is
dependent upon the wing loading, gross weight, and
speed of the generating aircraft. The vortices from
medium to heavy aircraft can be of extremely high
velocity and hazardous to smaller aircraft.
(See AIRCRAFT CLASSES.)
(See WAKE TURBULENCE.)
(Refer to AIM.)
VOT- A ground facility which emits a test signal to
check VOR receiver accuracy. Some VOTs are
available to the user while airborne, and others are
limited to ground use only.
(See AIRPORT/FACILITY DIRECTORY.)
(Refer to 14 CFR Part 91.)
(Refer to AIM.)
VR(See VFR MILITARY TRAINING ROUTES.)
VSCS(See VOICE SWITCHING AND CONTROL
SYSTEM.)
VTA(See VERTEX TIME OF ARRIVAL.)
VTOL AIRCRAFT(See VERTICAL TAKEOFF AND LANDING
AIRCRAFT.)
Pilot/Controller Glossary 2/14/08
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W
WA(See AIRMET.)
(See WEATHER ADVISORY.)
WAAS(See WIDE‐AREA AUGMENTATION SYSTEM.)
WAKE TURBULENCE- Phenomena resulting from
the passage of an aircraft through the atmosphere.
The term includes vortices, thrust stream turbulence,
jet blast, jet wash, propeller wash, and rotor wash
both on the ground and in the air.
(See AIRCRAFT CLASSES.)
(See JET BLAST.)
(See VORTICES.)
(Refer to AIM.)
WARNING AREA(See SPECIAL USE AIRSPACE.)
WAYPOINT- A predetermined geographical posi‐
tion used for route/instrument approach definition,
progress reports, published VFR routes, visual
reporting points or points for transitioning and/or
circumnavigating controlled and/or special use
airspace, that is defined relative to a VORTAC station
or in terms of latitude/longitude coordinates.
WEATHER ADVISORY- In aviation weather
forecast practice, an expression of hazardous weather
conditions not predicted in the area forecast, as they
affect the operation of air traffic and as prepared by
the NWS.
(See AIRMET.)
(See SIGMET.)
WHEN ABLE- When used in conjunction with ATC
instructions, gives the pilot the latitude to delay
compliance until a condition or event has been
reconciled. Unlike “pilot discretion,” when instruc‐
tions are prefaced “when able,” the pilot is expected
to seek the first opportunity to comply. Once a
maneuver has been initiated, the pilot is expected to
continue until the specifications of the instructions
have been met. “When able,” should not be used
when expeditious compliance is required.
WIDE‐AREA AUGMENTATION SYSTEM
(WAAS)- The WAAS is a satellite navigation system
consisting of the equipment and software which
augments the GPS Standard Positioning Service
(SPS). The WAAS provides enhanced integrity,
accuracy, availability, and continuity over and above
GPS SPS. The differential correction function
provides improved accuracy required for precision
approach.
WILCO- I have received your message, understand
it, and will comply with it.
WIND GRID DISPLAY- A display that presents the
latest forecasted wind data overlaid on a map of the
ARTCC area. Wind data is automatically entered and
updated periodically by transmissions from the
National Weather Service. Winds at specific
altitudes, along with temperatures and air pressure
can be viewed.
WIND SHEAR- A change in wind speed and/or wind
direction in a short distance resulting in a tearing or
shearing effect. It can exist in a horizontal or vertical
direction and occasionally in both.
WING TIP VORTICES(See VORTICES.)
WORDS TWICEa. As a request: “Communication is difficult.
Please say every phrase twice.”
b. As information: “Since communications are
difficult, every phrase in this message will be spoken
twice.”
WORLD AERONAUTICAL CHARTS(See AERONAUTICAL CHART.)
WS(See SIGMET.)
(See WEATHER ADVISORY.)
WST(See CONVECTIVE SIGMET.)
(See WEATHER ADVISORY.) 12346559798 谢谢，收到了 感觉永远是没法学完，除非我能获得永远的生命。 看啊看你，系诶下额