COMPOSITE SEPARATION- A method of separat‐
ing aircraft in a composite route system where, by
management of route and altitude assignments, a
combination of half the lateral minimum specified for
the area concerned and half the vertical minimum is
applied.
COMPULSORY REPORTING POINTS- Reporting
points which must be reported to ATC. They are
designated on aeronautical charts by solid triangles or
filed in a flight plan as fixes selected to define direct
routes. These points are geographical locations
which are defined by navigation aids/fixes. Pilots
should discontinue position reporting over compul‐
sory reporting points when informed by ATC that
their aircraft is in “radar contact.”
CONFLICT ALERT- A function of certain air traffic
control automated systems designed to alert radar
controllers to existing or pending situations between
tracked targets (known IFR or VFR aircraft) that
require his/her immediate attention/action.
(See MODE C INTRUDER ALERT.)
CONFLICT RESOLUTION- The resolution of
potential conflictions between aircraft that are radar
identified and in communication with ATC by
ensuring that radar targets do not touch. Pertinent
traffic advisories shall be issued when this procedure
is applied.
Note:This procedure shall not be provided utilizing
mosaic radar systems.
CONFORMANCE- The condition established when
an aircraft's actual position is within the conformance
region constructed around that aircraft at its position,
according to the trajectory associated with the
aircraft's Current Plan.
CONFORMANCE REGION- A volume, bounded
laterally, vertically, and longitudinally, within which
an aircraft must be at a given time in order to be in
conformance with the Current Plan Trajectory for that
aircraft. At a given time, the conformance region is
determined by the simultaneous application of the
lateral, vertical, and longitudinal conformance
bounds for the aircraft at the position defined by time
and aircraft's trajectory.
CONSOLAN- A low frequency, long‐distance
NAVAID used principally for transoceanic naviga‐
tions.
CONTACTa. Establish communication with (followed by the
name of the facility and, if appropriate, the frequency
to be used).
b. A flight condition wherein the pilot ascertains
the attitude of his/her aircraft and navigates by visual
reference to the surface.
(See CONTACT APPROACH.)
(See RADAR CONTACT.)
CONTACT APPROACH- An approach wherein an
aircraft on an IFR flight plan, having an air traffic
control authorization, operating clear of clouds with
at least 1 mile flight visibility and a reasonable
expectation of continuing to the destination airport in
those conditions, may deviate from the instrument
approach procedure and proceed to the destination
airport by visual reference to the surface. This
approach will only be authorized when requested by
the pilot and the reported ground visibility at the
destination airport is at least 1 statute mile.
(Refer to AIM.)
CONTAMINATED RUNWAY- A runway is
considered contaminated whenever standing water,
ice, snow, slush, frost in any form, heavy rubber, or
other substances are present. A runway is contami‐
nated with respect to rubber deposits or other
friction‐degrading substances when the average
friction value for any 500‐foot segment of the runway
within the ALD fails below the recommended
minimum friction level and the average friction value
in the adjacent 500‐foot segments falls below the
maintenance planning friction level.
CONTERMINOUS U.S.- The 48 adjoining States
and the District of Columbia.
Pilot/Controller Glossary 2/14/08
PCG C-6
CONTINENTAL UNITED STATES- The 49 States
located on the continent of North America and the
District of Columbia.
CONTINUE- When used as a control instruction
should be followed by another word or words
clarifying what is expected of the pilot. Example:
“continue taxi,” “continue descent,” “continue
inbound,” etc.
CONTROL AREA - A controlled airspace
extending upwards from a specified limit above the
earth.
CONTROL SECTOR- An airspace area of defined
horizontal and vertical dimensions for which a
controller or group of controllers has air traffic
control responsibility, normally within an air route
traffic control center or an approach control facility.
Sectors are established based on predominant traffic
flows, altitude strata, and controller workload.
Pilot‐communications during operations within a
sector are normally maintained on discrete frequen‐
cies assigned to the sector.
(See DISCRETE FREQUENCY.)
CONTROL SLASH- A radar beacon slash repre‐
senting the actual position of the associated aircraft.
Normally, the control slash is the one closest to the
interrogating radar beacon site. When ARTCC radar
is operating in narrowband (digitized) mode, the
control slash is converted to a target symbol.
CONTROLLED AIR SPACE- An airspace of
defined dimensions within which air traffic control
service is provided to IFR flights and to VFR flights
in accordance with the airspace classification.
a. Controlled airspace is a generic term that covers
Class A, Class B, Class C, Class D, and Class E
airspace.
b. Controlled airspace is also that airspace within
which all aircraft operators are subject to certain pilot
qualifications, operating rules, and equipment
requirem ents in 14 CFR Part 91 (for specific
operating requirements, please refer to 14 CFR
Part 91). For IFR operations in any class of controlled
airspace, a pilot must file an IFR flight plan and
receive an appropriate ATC clearance. Each Class B,
Class C, and Class D airspace area designated for an
airport contains at least one primary airport around
which the airspace is designated (for specific
designations and descriptions of the airspace classes,
please refer to 14 CFR Part 71).
c. Controlled airspace in the United States is
designated as follows:
1. CLASS A- Generally, that airspace from
18,000 feet MSL up to and including FL 600,
including the airspace overlying the waters within 12
nautical miles of the coast of the 48 contiguous States
and Alaska. Unless otherwise authorized, all persons
must operate their aircraft under IFR.
2. CLASS B- Generally, that airspace from the
surface to 10,000 feet MSL surrounding the nation's
busiest airports in terms of airport operations or
passenger enplanements. The configuration of each
Class B airspace area is individually tailored and
consists of a surface area and two or more layers
(some Class B airspaces areas resemble upside‐down
wedding cakes), and is designed to contain all
published instrument procedures once an aircraft
enters the airspace. An ATC clearance is required for
all aircraft to operate in the area, and all aircraft that
are so cleared receive separation services within the
airspace. The cloud clearance requirement for VFR
operations is “clear of clouds.”
3. CLASS C- Generally, that airspace from the
surface to 4,000 feet above the airport elevation
(charted in MSL) surrounding those airports that
have an operational control tower, are serviced by a
radar approach control, and that have a certain
number of IFR operations or passenger enplane‐
ments. Although the configuration of each Class C
area is individually tailored, the airspace usually
consists of a surface area with a 5 nautical mile (NM)
radius, a circle with a 10NM radius that extends no
lower than 1,200 feet up to 4,000 feet above the
airport elevation and an outer area that is not charted.
Each person must establish two‐way radio commu‐
nications with the ATC facility providing air traffic
services prior to entering the airspace and thereafter
maintain those communications while within the
airspace. VFR aircraft are only separated from IFR
aircraft within the airspace.
(See OUTER AREA.)
4. CLASS D- Generally, that airspace from the
surface to 2,500 feet above the airport elevation
(charted in MSL) surrounding those airports that
have an operational control tower. The configuration
of each Class D airspace area is individually tailored
and when instrument procedures are published, the
airspace will normally be designed to contain the
procedures. Arrival extensions for instrument
approach procedures may be Class D or Class E
Pilot/Controller Glossary 2/14/08
PCG C-7
airspace. Unless otherwise authorized, each person
must establish two‐way radio communications with
the ATC facility providing air traffic services prior to
entering the airspace and thereafter maintain those
communications while in the airspace. No separation
services are provided to VFR aircraft.
5. CLASS E- Generally, if the airspace is not
Class A, Class B, Class C, or Class D, and it is
controlled airspace, it is Class E airspace. Class E
airspace extends upward from either the surface or a
designated altitude to the overlying or adjacent
controlled airspace. When designated as a surface
area, the airspace will be configured to contain all
instrument procedures. Also in this class are Federal
airways, airspace beginning at either 700 or 1,200
feet AGL used to transition to/from the terminal or en
route environment, en route domestic, and offshore
airspace areas designated below 18,000 feet MSL.
Unless designated at a lower altitude, Class E
airspace begins at 14,500 MSL over the United
States, including that airspace overlying the waters
within 12 nautical miles of the coast of the 48
contiguous States and Alaska, up to, but not
including 18,000 feet MSL, and the airspace above
FL 600.
CONTROLLED AIRSPACE - An airspace
of defined dimensions within which air traffic control
service is provided to IFR flights and to VFR flights
in accordance with the airspace classification.
Note:Controlled airspace is a generic term which
covers ATS airspace Classes A, B, C, D, and E.
CONTROLLED TIME OF ARRIVAL- Arrival time
assigned during a Traffic Management Program. This
time may be modified due to adjustments or user
options.
CONTROLLER(See AIR TRAFFIC CONTROL SPECIALIST.)
CONTROLLER - A person authorized to
provide air traffic control services.
CONTROLLER PILOT DATA LINK COMMU‐
NICATIONS (CPDLC)- A two-way digital very
high frequency (VHF) air/ground communications
system that conveys textual air traffic control
messages between controllers and pilots.
CONVECTIVE SIGMET- A weather advisory
concerning convective weather significant to the
safety of all aircraft. Convective SIGMETs are issued
for tornadoes, lines of thunderstorms, embedded
thunderstorms of any intensity level, areas of
thunderstorms greater than or equal to VIP level 4
with an area coverage of 4
/10 (40%) or more, and hail
3
/4 inch or greater.
(See AIRMET.)
(See AWW.)
(See CWA.)
(See SIGMET.)
(Refer to AIM.)
CONVECTIVE SIGNIFICANT METEOROLOG‐
ICAL INFORMATION(See CONVECTIVE SIGMET.)
COORDINATES- The intersection of lines of
reference, usually expressed in degrees/minutes/
seconds of latitude and longitude, used to determine
position or location.
COORDINATION FIX- The fix in relation to which
facilities will handoff, transfer control of an aircraft,
or coordinate flight progress data. For terminal
facilities, it may also serve as a clearance for arriving
aircraft.
COPTER(See HELICOPTER.)
CORRECTION- An error has been made in the
transmission and the correct version follows.
COUPLED APPROACH- A coupled approach is an
instrument approach performed by the aircraft
autopilot which is receiving position information
and/or steering commands from onboard navigation
equipment. In general, coupled nonprecision ap‐
proaches must be discontinued and flown manually
at altitudes lower than 50 feet below the minimum
descent altitude, and coupled precision approaches
must be flown manually below 50 feet AGL.
Note:Coupled and autoland approaches are flown
in VFR and IFR. It is common for carriers to require
their crews to fly coupled approaches and autoland
approaches (if certified) when the weather
conditions are less than approximately 4,000 RVR.
(See AUTOLAND APPROACH.)
COURSEa. The intended direction of flight in the horizontal
plane measured in degrees from north.
b. The ILS localizer signal pattern usually
specified as the front course or the back course.
Pilot/Controller Glossary 2/14/08
PCG C-8
c. The intended track along a straight, curved, or
segmented MLS path.
(See BEARING.)
(See INSTRUMENT LANDING SYSTEM.)
(See MICROWAVE LANDING SYSTEM.)
(See RADIAL.)
CPDLC(See CONTROLLER PILOT DATA LINK
COMMUNICATIONS.)
CPL -
(See ICAO term CURRENT FLIGHT PLAN.)
CRITICAL ENGINE- The engine which, upon
failure, would most adversely affect the performance
or handling qualities of an aircraft.
CROSS (FIX) AT (ALTITUDE)- Used by ATC
when a specific altitude restriction at a specified fix
is required.
CROSS (FIX) AT OR ABOVE (ALTITUDE)- Used
by ATC when an altitude restriction at a specified fix
is required. It does not prohibit the aircraft from
crossing the fix at a higher altitude than specified;
however, the higher altitude may not be one that will
violate a succeeding altitude restriction or altitude
assignment.
(See ALTITUDE RESTRICTION.)
(Refer to AIM.)
CROSS (FIX) AT OR BELOW (ALTITUDE)-
Used by ATC when a maximum crossing altitude at
a specific fix is required. It does not prohibit the
aircraft from crossing the fix at a lower altitude;
however, it must be at or above the minimum IFR
altitude.
(See ALTITUDE RESTRICTION.)
(See MINIMUM IFR ALTITUDES.)
(Refer to 14 CFR Part 91.)
CROSSWINDa. When used concerning the traffic pattern, the
word means “crosswind leg.”
(See TRAFFIC PATTERN.)
b. When used concerning wind conditions, the
word means a wind not parallel to the runway or the
path of an aircraft.
(See CROSSWIND COMPONENT.)
CROSSWIND COMPONENT- The wind compo‐
nent measured in knots at 90 degrees to the
longitudinal axis of the runway.
CRUISE- Used in an ATC clearance to authorize a
pilot to conduct flight at any altitude from the
minimum IFR altitude up to and including the
altitude specified in the clearance. The pilot may
level off at any intermediate altitude within this block
of airspace. Climb/descent within the block is to be
made at the discretion of the pilot. However, once the
pilot starts descent and verbally reports leaving an
altitude in the block, he/she may not return to that
altitude without additional ATC clearance. Further, it
is approval for the pilot to proceed to and make an
approach at destination airport and can be used in
conjunction with:
a. An airport clearance limit at locations with a
standard/special instrument approach procedure. The
CFRs require that if an instrument letdown to an
airport is necessary, the pilot shall make the letdown
in accordance with a standard/special instrument
approach procedure for that airport, or
b. An airport clearance limit at locations that are
within/below/outside controlled airspace and with‐
out a standard/special instrument approach
procedure. Such a clearance is NOT AUTHORIZA‐
TION for the pilot to descend under IFR conditions
below the applicable minimum IFR altitude nor does
it imply that ATC is exercising control over aircraft
in Class G airspace; however, it provides a means for
the aircraft to proceed to destination airport, descend,
and land in accordance with applicable CFRs
governing VFR flight operations. Also, this provides
search and rescue protection until such time as the
IFR flight plan is closed.
(See INSTRUMENT APPROACH
PROCEDURE.)
CRUISE CLIMB- A climb technique employed by
aircraft, usually at a constant power setting, resulting
in an increase of altitude as the aircraft weight
decreases.
CRUISING ALTITUDE- An altitude or flight level
maintained during en route level flight. This is a
constant altitude and should not be confused with a
cruise clearance.
(See ALTITUDE.)
(See ICAO term CRUISING LEVEL.)
CRUISING LEVEL(See CRUISING ALTITUDE.)
CRUISING LEVEL - A level maintained
during a significant portion of a flight.
Pilot/Controller Glossary 2/14/08
PCG C-9
CT MESSAGE- An EDCT time generated by the
ATCSCC to regulate traffic at arrival airports.
Normally, a CT message is automatically transferred
from the Traffic Management System computer to the
NAS en route computer and appears as an EDCT. In
the event of a communication failure between the
TMS and the NAS, the CT message can be manually
entered by the TMC at the en route facility.
CTA(See CONTROLLED TIME OF ARRIVAL.)
(See ICAO term CONTROL AREA.)
CTAF(See COMMON TRAFFIC ADVISORY
FREQUENCY.)
CTAS(See CENTER TRACON AUTOMATION
SYSTEM.)
CTRD(See CERTIFIED TOWER RADAR DISPLAY.)
CURRENT FLIGHT PLAN - The flight
plan, including changes, if any, brought about by
subsequent clearances.
CURRENT PLAN- The ATC clearance the aircraft
has received and is expected to fly.
CVFP APPROACH(See CHARTED VISUAL FLIGHT PROCEDURE
APPROACH.)
CWA(See CENTER WEATHER ADVISORY and
WEATHER ADVISORY.)
Pilot/Controller Glossary 2/14/08
PCG D-1
D
D‐ATIS(See DIGITAL‐AUTOMATIC TERMINAL
INFORMATION SERVICE.)
DA -
(See ICAO Term DECISION
ALTITUDE/DECISION HEIGHT.)
DAIR(See DIRECT ALTITUDE AND IDENTITY
READOUT.)
DANGER AREA - An airspace of defined
dimensions within which activities dangerous to the
flight of aircraft may exist at specified times.
Note:The term “Danger Area” is not used in
reference to areas within the United States or any
of its possessions or territories.
DAS(See DELAY ASSIGNMENT.)
DATA BLOCK(See ALPHANUMERIC DISPLAY.)
DEAD RECKONING- Dead reckoning, as applied
to flying, is the navigation of an airplane solely by
means of computations based on airspeed, course,
heading, wind direction, and speed, groundspeed,
and elapsed time.
DECIS ION ALTITUDE/DECIS ION HEIGHT
- A specified altitude or height (A/H) in the
precision approach at which a missed approach must
be initiated if the required visual reference to
continue the approach has not been established.
Note 1:Decision altitude is referenced to
mean sea level and decision height is
referenced to the threshold elevation.
Note 2:The required visual reference means that
section of the visual aids or of the approach area
which should have been in view for sufficient time
for the pilot to have made an assessment of the
aircraft position and rate of change of position, in
relation to the desired flight path.
DECISION HEIGHT- With respect to the operation
of aircraft, means the height at which a decision must
be made during an ILS, MLS, or PAR instrument
approach to either continue the approach or to execute
a missed approach.
(See ICAO term DECISION
ALTITUDE/DECISION HEIGHT.)
DECODER- The device used to decipher signals
received from ATCRBS transponders to effect their
display as select codes.
(See CODES.)
(See RADAR.)
DEFENSE VIS UAL FLIGHT RULES- Rules
applicable to flights within an ADIZ conducted under
the visual flight rules in 14 CFR Part 91.
(See AIR DEFENSE IDENTIFICATION ZONE.)
(Refer to 14 CFR Part 91.)
(Refer to 14 CFR Part 99.)
DELAY ASSIGNMENT (DAS)- Delays are distrib‐
uted to aircraft based on the traffic management
program parameters. The delay assignment is
calculated in 15-minute increments and appears as a
table in Enhanced Traffic Management System
(ETMS).
DELAY INDEFINITE (REASON IF KNOWN)
EXPECT FURTHER CLEARANCE (TIME)- Used
by ATC to inform a pilot when an accurate estimate
of the delay time and the reason for the delay cannot
immediately be determined; e.g., a disabled aircraft
on the runway, terminal or center area saturation,
weather below landing minimums, etc.
(See EXPECT FURTHER CLEARANCE (TIME).)
DELAY TIME- The amount of time that the arrival
must lose to cross the meter fix at the assigned meter
fix time. This is the difference between ACLT and
VTA.
DEPARTURE CENTER- The ARTCC having
jurisdiction for the airspace that generates a flight to
the impacted airport.
DEPARTURE CONTROL- A function of an
approach control facility providing air traffic control
service for departing IFR and, under certain
conditions, VFR aircraft.
(See APPROACH CONTROL FACILITY.)
(Refer to AIM.)
DEPARTURE SEQUENCING PROGRAM- A
program designed to assist in achieving a specified
interval over a common point for departures.
Pilot/Controller Glossary 2/14/08
PCG D-2
DEPARTURE TIME- The time an aircraft becomes
airborne.
DESCENT SPEED ADJUSTMENTS- Speed decel‐
eration calculations made to determine an accurate
VTA. These calculations start at the transition point
and use arrival speed segments to the vertex.
DESIRED COURSEa. True- A predetermined desired course direction
to be followed (measured in degrees from true north).
b. Magnetic- A predetermined desired course
direction to be followed (measured in degrees from
local magnetic north).
DESIRED TRACK- The planned or intended track
between two waypoints. It is measured in degrees
from either magnetic or true north. The instantaneous
angle may change from point to point along the great
circle track between waypoints.
DETRESFA (DISTRESS PHASE) - The
code word used to designate an emergency phase
wherein there is reasonable certainty that an aircraft
and its occupants are threatened by grave and
imminent danger or require immediate assistance.
DEVIATIONSa. A departure from a current clearance, such as an
off course maneuver to avoid weather or turbulence.
b. Where specifically authorized in the CFRs and
requested by the pilot, ATC may permit pilots to
deviate from certain regulations.
(Refer to AIM.)
DF(See DIRECTION FINDER.)
DF APPROACH PROCEDURE- Used under
emergency conditions where another instrument
approach procedure cannot be executed. DF guidance
for an instrument approach is given by ATC facilities
with DF capability.
(See DF GUIDANCE.)
(See DIRECTION FINDER.)
(Refer to AIM.)
DF FIX- The geographical location of an aircraft
obtained by one or more direction finders.
(See DIRECTION FINDER.)
DF GUIDANCE- Headings provided to aircraft by
facilities equipped with direction finding equipment.
These headings, if followed, will lead the aircraft to
a predetermined point such as the DF station or an
airport. DF guidance is given to aircraft in distress or
to other aircraft which request the service. Practice
DF guidance is provided when workload permits.
(See DIRECTION FINDER.)
(See DF FIX.)
(Refer to AIM.)
DF STEER(See DF GUIDANCE.)
DH(See DECISION HEIGHT.)
DH -
(See ICAO Term DECISION ALTITUDE/
DECISION HEIGHT.)
DIGITAL‐AUTOMATIC TERMINAL INFORMA‐
TION SERVICE (D‐ATIS)- The service provides
text messages to aircraft, airlines, and other users
outside the standard reception range of conventional
ATIS via landline and data link communications to
the cockpit. Also, the service provides a computersynthesized voice message that can be transmitted to
all aircraft within range of existing transmitters. The
Term inal Data Link System (TDLS) D‐ATIS
application uses weather inputs from local automated
weather sources or manually entered meteorological
data together with preprogrammed menus to provide
standard information to users. Airports with D‐ATIS
capability are listed in the Airport/Facility Directory.
DIGITAL TARGET- A computer-generated symbol
representing an aircraft's position, based on a primary
return or radar beacon reply, shown on a digital
display.
DIGITAL TERMINAL AUTOMATION SYSTEM
(DTAS)- A system where digital radar and beacon
data is presented on digital displays and the
operational program monitors the system perfor‐
mance on a real-time basis.
DIGITIZED TARGET- A computer-generated
indication shown on an analog radar display resulting
from a primary radar return or a radar beacon reply.
DIRECT- Straight line flight between two naviga‐
tional aids, fixes, points, or any combination thereof.
When used by pilots in describing off‐airway routes,
points defining direct route segments become
compulsory reporting points unless the aircraft is
under radar contact.
DIRECT ALTITUDE AND IDENTITY READ‐
OUT- The DAIR System is a modification to the
Pilot/Controller Glossary 2/14/08
PCG D-3
AN/TPX‐42 Interrogator System. The Navy has two
adaptations of the DAIR System‐Carrier Air Traffic
Control Direct Altitude and Identification Readout
System for Aircraft Carriers and Radar Air Traffic
Control Facility Direct Altitude and Identity Readout
System for land‐based terminal operations. The
DAIR detects, tracks, and predicts secondary radar
aircraft targets. Targets are displayed by means of
computer‐generated symbols and alphanumeric
characters depicting flight identification, altitude,
ground speed, and flight plan data. The DAIR System
is capable of interfacing with ARTCCs.
DIRECTION FINDER- A radio receiver equipped
with a directional sensing antenna used to take
bearings on a radio transmitter. Specialized radio
direction finders are used in aircraft as air navigation
aids. Others are ground‐based, primarily to obtain a
“fix” on a pilot requesting orientation assistance or to
locate downed aircraft. A location “fix” is established
by the intersection of two or more bearing lines
plotted on a navigational chart using either two
separately located Direction Finders to obtain a fix on
an aircraft or by a pilot plotting the bearing
indications of his/her DF on two separately located
ground‐based transmitters, both of which can be
identified on his/her chart. UDFs receive signals in
the ultra high frequency radio broadcast band; VDFs
in the very high frequency band; and UVDFs in both
bands. ATC provides DF service at those air traffic
control towers and flight service stations listed in the
Airport/Facility Directory and the DOD FLIP IFR En
Route Supplement.
(See DF FIX.)
(See DF GUIDANCE.)
DIRECTLY BEHIND- An aircraft is considered to
be operating directly behind when it is following the
actual flight path of the lead aircraft over the surface
of the earth except when applying wake turbulence
separation criteria.
DISCRETE BEACON CODE(See DISCRETE CODE.)
DISCRETE CODE- As used in the Air Traffic
Control Radar Beacon System (ATCRBS), any one
of the 4096 selectable Mode 3/A aircraft transponder
codes except those ending in zero zero; e.g., discrete
codes: 0010, 1201, 2317, 7777; nondiscrete codes:
0100, 1200, 7700. Nondiscrete codes are normally
reserved for radar facilities that are not equipped with
discrete decoding capability and for other purposes
such as emergencies (7700), VFR aircraft (1200), etc.
(See RADAR.)
(Refer to AIM.)
DIS CRETE FREQUENCY- A separate radio
frequency for use in direct pilot‐controller commu‐
nications in air traffic control which reduces
frequency congestion by controlling the number of
aircraft operating on a particular frequency at one
time. Discrete frequencies are normally designated
for each control sector in en route/terminal ATC
facilities. Discrete frequencies are listed in the
Airport/Facility Directory and the DOD FLIP IFR En
Route Supplement.
(See CONTROL SECTOR.)
DISPLACED THRESHOLD- A threshold that is
located at a point on the runway other than the
designated beginning of the runway.
(See THRESHOLD.)
(Refer to AIM.)
DISTANCE MEASURING EQUIPMENT- Equip‐
ment (airborne and ground) used to measure, in
nautical miles, the slant range distance of an aircraft
from the DME navigational aid.
(See MICROWAVE LANDING SYSTEM.)
(See TACAN.)
(See VORTAC.)
DISTRESS- A condition of being threatened by
serious and/or imminent danger and of requiring
immediate assistance.
DIVE BRAKES(See SPEED BRAKES.)
DIVERSE VECTOR AREA- In a radar environ‐
ment, that area in which a prescribed departure route
is not required as the only suitable route to avoid
obstacles. The area in which random radar vectors
below the MVA/MIA, established in accordance with
the TERPS criteria for diverse departures, obstacles
and terrain avoidance, may be issued to departing
aircraft.
DIVERSION (DVRSN)- Flights that are required to
land at other than their original destination for
reasons beyond the control of the pilot/company, e.g.
periods of significant weather.
DME(See DISTANCE MEASURING EQUIPMENT.)
Pilot/Controller Glossary 2/14/08
PCG D-4
DME FIX- A geographical position determined by
reference to a navigational aid which provides
distance and azimuth information. It is defined by a
specific distance in nautical miles and a radial,
azimuth, or course (i.e., localizer) in degrees
magnetic from that aid.
(See DISTANCE MEASURING EQUIPMENT.)
(See FIX.)
(See MICROWAVE LANDING SYSTEM.)
DME SEPARATION- Spacing of aircraft in terms of
distances (nautical miles) determined by reference to
distance measuring equipment (DME).
(See DISTANCE MEASURING EQUIPMENT.)
DOD FLIP- Department of Defense Flight Informa‐
tion Publications used for flight planning, en route,
and terminal operations. FLIP is produced by the
National Imagery and Mapping Agency (NIMA) for
world‐wide use. United States Government Flight
Information Publications (en route charts and
instrument approach procedure charts) are incorpo‐
rated in DOD FLIP for use in the National Airspace
System (NAS).
DOMESTIC AIRSPACE- Airspace which overlies
the continental land mass of the United States plus
Hawaii and U.S. possessions. Domestic airspace
extends to 12 miles offshore.
DOWNBURST- A strong downdraft which induces
an outburst of damaging winds on or near the ground.
Damaging winds, either straight or curved, are highly
divergent. The sizes of downbursts vary from 1/2
mile or less to more than 10 miles. An intense
downburst often causes widespread damage. Damag‐
ing winds, lasting 5 to 30 minutes, could reach speeds
as high as 120 knots.
DOWNWIND LEG(See TRAFFIC PATTERN.)
DP(See INSTRUMENT DEPARTURE PROCEDURE.)
DRAG CHUTE- A parachute device installed on
certain aircraft which is deployed on landing roll to
assist in deceleration of the aircraft.
DSP(See DEPARTURE SEQUENCING PROGRAM.)
DT(See DELAY TIME.)
DTAS(See DIGITAL TERMINAL AUTOMATION
SYSTEM.)
DUE REGARD- A phase of flight wherein an
aircraft commander of a State‐operated aircraft
assumes responsibility to separate his/her aircraft
from all other aircraft.
(See also FAAO JO 7110.65, Para 1-2-1, WORD
MEANINGS.)
DUTY RUNWAY(See RUNWAY IN USE/ACTIVE RUNWAY/DUTY
RUNWAY.)
DVA(See DIVERSE VECTOR AREA.)
DVFR(See DEFENSE VISUAL FLIGHT RULES.)
DVFR FLIGHT PLAN- A flight plan filed for a VFR
aircraft which intends to operate in airspace within
which the ready identification, location, and control
of aircraft are required in the interest of national
security.
DVRSN(See DIVERSION.)
DYNAMIC- Continuous review, evaluation, and
change to meet demands.
DYNAMIC RESTRICTIONS- Those restrictions
imposed by the local facility on an “as needed” basis
to manage unpredictable fluctuations in traffic
demands.
Pilot/Controller Glossary 2/14/08
PCG E-1
E
EAS(See EN ROUTE AUTOMATION SYSTEM.)
EDCT(See EXPECT DEPARTURE CLEARANCE
TIME.)
EFC(See EXPECT FURTHER CLEARANCE (TIME).)
ELT(See EMERGENCY LOCATOR TRANSMITTER.)
EMERGENCY- A distress or an urgency condition.
EMERGENCY LOCATOR TRANSMITTER- A
radio transmitter attached to the aircraft structure
which operates from its own power source on
121.5 MHz and 243.0 MHz. It aids in locating
downed aircraft by radiating a downward sweeping
audio tone, 2‐4 times per second. It is designed to
function without human action after an accident.
(Refer to 14 CFR Part 91.)
(Refer to AIM.)
E‐MSAW(See EN ROUTE MINIMUM SAFE ALTITUDE
WARNING.)
EN ROUTE AIR TRAFFIC CONTROL SER‐
VICES- Air traffic control service provided aircraft
on IFR flight plans, generally by centers, when these
aircraft are operating between departure and
destination terminal areas. When equipment, capa‐
bilities, and controller workload permit, certain
advisory/assistance services may be provided to VFR
aircraft.
(See AIR ROUTE TRAFFIC CONTROL
CENTER.)
(Refer to AIM.)
EN ROUTE AUTOMATION SYSTEM (EAS)- The
complex integrated environment consisting of
situation display systems, surveillance systems and
flight data processing, remote devices, decision
support tools, and the related communications
equipment that form the heart of the automated IFR
air traffic control system. It interfaces with automated
terminal systems and is used in the control of en route
IFR aircraft.
(Refer to AIM.)
EN ROUTE CHARTS(See AERONAUTICAL CHART.)
EN ROUTE DESCENT- Descent from the en route
cruising altitude which takes place along the route of
flight.
EN ROUTE FLIGHT ADVISORY SERVICE- A
service specifically designed to provide, upon pilot
request, timely weather information pertinent to
his/her type of flight, intended route of flight, and
altitude. The FSSs providing this service are listed in
the Airport/Facility Directory.
(See FLIGHT WATCH.)
(Refer to AIM.)
EN ROUTE HIGH ALTITUDE CHARTS(See AERONAUTICAL CHART.)
EN ROUTE LOW ALTITUDE CHARTS(See AERONAUTICAL CHART.)
EN ROUTE MINIMUM SAFE ALTITUDE WARN‐
ING- A function of the EAS that aids the controller
by providing an alert when a tracked aircraft is below
or predicted by the computer to go below a
predetermined minimum IFR altitude (MIA).
EN ROUTE SPACING PROGRAM (ESP)- A
program designed to assist the exit sector in
achieving the required in‐trail spacing.
EN ROUTE TRANSITIONa. Conventional STARs/SIDs. The portion of a
SID/STAR that connects to one or more en route
airway/jet route.
b. RNAV STARs/SIDs. The portion of a STAR
preceding the common route or point, or for a SID the
portion following, that is coded for a specific en route
fix, airway or jet route.
ESP(See EN ROUTE SPACING PROGRAM.)
ESTABLISHED-To be stable or fixed on a route,
route segment, altitude, heading, etc.
ESTIMATED ELAPSED TIME - The
estimated time required to proceed from one
significant point to another.
(See ICAO Term TOTAL ESTIMATED ELAPSED
TIME.)
Pilot/Controller Glossary 2/14/08
PCG E-2
ESTIMATED OFF‐BLOCK TIME - The
estimated time at which the aircraft will commence
movement associated with departure.
ESTIMATED POSITION ERROR (EPE)-
(See Required Navigation Performance)
ESTIMATED TIME OF ARRIVAL- The time the
flight is estimated to arrive at the gate (scheduled
operators) or the actual runway on times for
nonscheduled operators.
ESTIMATED TIME EN ROUTE- The estimated
flying time from departure point to destination
(lift‐off to touchdown).
ETA(See ESTIMATED TIME OF ARRIVAL.)
ETE(See ESTIMATED TIME EN ROUTE.)
EXECUTE MISSED APPROACH- Instructions
issued to a pilot making an instrument approach
which means continue inbound to the missed
approach point and execute the missed approach
procedure as described on the Instrument Approach
Procedure Chart or as previously assigned by ATC.
The pilot may climb immediately to the altitude
specified in the missed approach procedure upon
making a missed approach. No turns should be
initiated prior to reaching the missed approach point.
When conducting an ASR or PAR approach, execute
the assigned missed approach procedure immediately
upon receiving instructions to “execute missed
approach.”
(Refer to AIM.)
EXPECT (ALTITUDE) AT (TIME) or (FIX)- Used
under certain conditions to provide a pilot with an
altitude to be used in the event of two‐way
communications failure. It also provides altitude
information to assist the pilot in planning.
(Refer to AIM.)
EXPECT DEPARTURE CLEARANCE TIME
(EDCT)- The runway release time assigned to an
aircraft in a traffic management program and shown
on the flight progress strip as an EDCT.
(See GROUND DELAY PROGRAM.)
EXPECT FURTHER CLEARANCE (TIME)- The
time a pilot can expect to receive clearance beyond a
clearance limit.
EXPECT FURTHER CLEARANCE VIA (AIR‐
WAYS, ROUTES OR FIXES)- Used to inform a
pilot of the routing he/she can expect if any part of the
route beyond a short range clearance limit differs
from that filed.
EXPEDITE- Used by ATC when prompt com‐
pliance is required to avoid the development of an
imminent situation. Expedite climb/descent normal‐
ly indicates to a pilot that the approximate best rate
of climb/descent should be used without requiring an
exceptional change in aircraft handling characteris‐
tics.
Pilot/Controller Glossary 2/14/08
PCG F-1
F
FAF(See FINAL APPROACH FIX.)
FAST FILE- A system whereby a pilot files a flight
plan via telephone that is tape recorded and then
transcribed for transmission to the appropriate air
traffic facility. Locations having a fast file capability
are contained in the Airport/Facility Directory.
(Refer to AIM.)
FAWP- Final Approach Waypoint
FCLT(See FREEZE CALCULATED LANDING TIME.)
FEATHERED PROPELLER- A propeller whose
blades have been rotated so that the leading and
trailing edges are nearly parallel with the aircraft
flight path to stop or minimize drag and engine
rotation. Normally used to indicate shutdown of a
reciprocating or turboprop engine due to malfunc‐
tion.
FEDERAL AIRWAYS(See LOW ALTITUDE AIRWAY STRUCTURE.)
FEEDER FIX- The fix depicted on Instrument
Approach Procedure Charts which establishes the
starting point of the feeder route.
FEEDER ROUTE- A route depicted on instrument
approach procedure charts to designate routes for
aircraft to proceed from the en route structure to the
initial approach fix (IAF).
(See INSTRUMENT APPROACH
PROCEDURE.)
FERRY FLIGHT- A flight for the purpose of:
a. Returning an aircraft to base.
b. Delivering an aircraft from one location to
another.
c. Moving an aircraft to and from a maintenance
base.- Ferry flights, under certain conditions, may be
conducted under terms of a special flight permit.
FIELD ELEVATION(See AIRPORT ELEVATION.)
FILED- Normally used in conjunction with flight
plans, meaning a flight plan has been submitted to
ATC.
FILED EN ROUTE DELAY- Any of the following
preplanned delays at points/areas along the route of
flight which require special flight plan filing and
handling techniques.
a. Terminal Area Delay. A delay within a terminal
area for touch‐and‐go, low approach, or other
terminal area activity.
b. Special Use Airspace Delay. A delay within a
Military Operations Area, Restricted Area, Warning
Area, or ATC Assigned Airspace.
c. Aerial Refueling Delay. A delay within an
Aerial Refueling Track or Anchor.
FILED FLIGHT PLAN- The flight plan as filed with
an ATS unit by the pilot or his/her designated
representative without any subsequent changes or
clearances.
FINAL- Commonly used to mean that an aircraft is
on the final approach course or is aligned with a
landing area.
(See FINAL APPROACH COURSE.)
(See FINAL APPROACH‐IFR.)
(See SEGMENTS OF AN INSTRUMENT
APPROACH PROCEDURE.)
FINAL APPROACH - That part of an
instrument approach procedure which commences at
the specified final approach fix or point, or where
such a fix or point is not specified.
a. At the end of the last procedure turn, base turn
or inbound turn of a racetrack procedure, if specified;
or
b. At the point of interception of the last track
specified in the approach procedure; and ends at a
point in the vicinity of an aerodrome from which:
1. A landing can be made; or
2. A missed approach procedure is initiated.
FINAL APPROACH COURSE- A bearing/radial/
track of an instrument approach leading to a runway
or an extended runway centerline all without regard
to distance.
FINAL APPROACH FIX- The fix from which the
final approach (IFR) to an airport is executed and
which identifies the beginning of the final approach
segment. It is designated on Government charts by
the Maltese Cross symbol for nonprecision
Pilot/Controller Glossary 2/14/08
PCG F-2
approaches and the lightning bolt symbol for
precision approaches; or when ATC directs a
lower‐than‐published glideslope/path intercept alti‐
tude, it is the resultant actual point of the
glideslope/path intercept.
(See FINAL APPROACH POINT.)
(See GLIDESLOPE INTERCEPT ALTITUDE.)
(See SEGMENTS OF AN INSTRUMENT
APPROACH PROCEDURE.)
FINAL APPROACH‐IFR- The flight path of an
aircraft which is inbound to an airport on a final
instrument approach course, beginning at the final
approach fix or point and extending to the airport or
the point where a circle‐to‐land maneuver or a missed
approach is executed.
(See FINAL APPROACH COURSE.)
(See FINAL APPROACH FIX.)
(See FINAL APPROACH POINT.)
(See SEGMENTS OF AN INSTRUMENT
APPROACH PROCEDURE.)
(See ICAO term FINAL APPROACH.)
FINAL APPROACH POINT- The point, applicable
only to a nonprecision approach with no depicted
FAF (such as an on airport VOR), where the aircraft
is established inbound on the final approach course
from the procedure turn and where the final approach
descent may be commenced. The FAP serves as the
FAF and identifies the beginning of the final
approach segment.
(See FINAL APPROACH FIX.)
(See SEGMENTS OF AN INSTRUMENT
APPROACH PROCEDURE.)
FINAL APPROACH SEGMENT(See SEGMENTS OF AN INSTRUMENT
APPROACH PROCEDURE.)
FINAL APPROACH SEGMENT - That
segment of an instrument approach procedure in
which alignment and descent for landing are
accomplished.
FINAL CONTROLLER- The controller providing
information and final approach guidance during PAR
and ASR approaches utilizing radar equipment.
(See RADAR APPROACH.)
FINAL GUARD SERVICE- A value added service
provided in conjunction with LAA/RAA only during
periods of significant and fast changing weather
conditions that may affect landing and takeoff
operations.
FINAL MONITOR AID- A high resolution color
display that is equipped with the controller alert
system hardware/software which is used in the
precision runway monitor (PRM) system. The
display includes alert algorithms providing the target
predictors, a color change alert when a target
penetrates or is predicted to penetrate the no
transgression zone (NTZ), a color change alert if the
aircraft transponder becomes inoperative, synthe‐
sized voice alerts, digital mapping, and like features
contained in the PRM system.
(See RADAR APPROACH.)
FINAL MONITOR CONTROLLER- Air Traffic
Control Specialist assigned to radar monitor the
flight path of aircraft during simultaneous parallel
and simultaneous close parallel ILS approach
operations. Each runway is assigned a final monitor
controller during simultaneous parallel and simulta‐
neous close parallel ILS approaches. Final monitor
controllers shall utilize the Precision Runway
Monitor (PRM) system during simultaneous close
parallel ILS approaches.
FIR(See FLIGHT INFORMATION REGION.)
FIRST TIER CENTER- The ARTCC immediately
adjacent to the impacted center.
FIX- A geographical position determined by visual
reference to the surface, by reference to one or more
radio NAVAIDs, by celestial plotting, or by another
navigational device.
FIX BALANCING- A process whereby aircraft are
evenly distributed over several available arrival fixes
reducing delays and controller workload.
FLAG- A warning device incorporated in certain
airborne navigation and flight instruments indicating
that:
a. Instruments are inoperative or otherwise not
operating satisfactorily, or
b. Signal strength or quality of the received signal
falls below acceptable values.
FLAG ALARM(See FLAG.)
FLAMEOUT- An emergency condition caused by a
loss of engine power.
FLAMEOUT PATTERN- An approach normally
conducted by a single‐engine military aircraft
experiencing loss or anticipating loss of engine
Pilot/Controller Glossary 2/14/08
PCG F-3
power or control. The standard overhead approach
starts at a relatively high altitude over a runway
(“high key”) followed by a continuous 180 degree
turn to a high, wide position (“low key”) followed by
a continuous 180 degree turn final. The standard
straight‐in pattern starts at a point that results in a
straight‐in approach with a high rate of descent to the
runway. Flameout approaches terminate in the type
approach requested by the pilot (normally fullstop).
FLIGHT CHECK- A call‐sign prefix used by FAA
aircraft engaged in flight inspection/certification of
navigational aids and flight procedures. The word
“recorded” may be added as a suffix; e.g., “Flight
Check 320 recorded” to indicate that an automated
flight inspection is in progress in terminal areas.
(See FLIGHT INSPECTION.)
(Refer to AIM.)
FLIGHT FOLLOWING(See TRAFFIC ADVISORIES.)
FLIGHT INFORMATION REGION- An airspace of
defined dimensions within which Flight Information
Service and Alerting Service are provided.
a. Flight Information Service. A service provided
for the purpose of giving advice and information
useful for the safe and efficient conduct of flights.
b. Alerting Service. A service provided to notify
appropriate organizations regarding aircraft in need
of search and rescue aid and to assist such
organizations as required.
FLIGHT INFORMATION SERVICE- A service
provided for the purpose of giving advice and
information useful for the safe and efficient conduct
of flights.
FLIGHT INSPECTION- Inflight investigation and
evaluation of a navigational aid to determine whether
it meets established tolerances.
(See FLIGHT CHECK.)
(See NAVIGATIONAL AID.)
FLIGHT LEVEL- A level of constant atmospheric
pressure related to a reference datum of 29.92 inches
of mercury. Each is stated in three digits that represent
hundreds of feet. For example, flight level (FL) 250
represents a barometric altimeter indication of
25,000 feet; FL 255, an indication of 25,500 feet.
(See ICAO term FLIGHT LEVEL.)
FLIGHT LEVEL - A surface of constant
atmospheric pressure which is related to a specific
pressure datum, 1013.2 hPa (1013.2 mb), and is
separated from other such surfaces by specific
pressure intervals.
Note 1:A pressure type altimeter calibrated in
accordance with the standard atmosphere:
a. When set to a QNH altimeter setting, will
indicate altitude;
b. When set to a QFE altimeter setting, will
indicate height above the QFE reference datum;
and
c. When set to a pressure of 1013.2 hPa
(1013.2 mb), may be used to indicate flight levels.
Note 2:The terms `height' and `altitude,' used in
Note 1 above, indicate altimetric rather than
geometric heights and altitudes.
FLIGHT LINE- A term used to describe the precise
movement of a civil photogrammetric aircraft along
a predetermined course(s) at a predetermined altitude
during the actual photographic run.
FLIGHT MANAGEMENT SYSTEMS- A comput‐
er system that uses a large data base to allow routes
to be preprogrammed and fed into the system by
means of a data loader. The system is constantly
updated with respect to position accuracy by
reference to conventional navigation aids. The
sophisticated program and its associated data base
insures that the most appropriate aids are automati‐
cally selected during the information update cycle.
FLIGHT MANAGEMENT SYSTEM PROCE‐
DURE- An arrival, departure, or approach procedure
developed for use by aircraft with a slant (/) E or slant
(/) F equipment suffix.
FLIGHT PATH- A line, course, or track along which
an aircraft is flying or intended to be flown.
(See COURSE.)
(See TRACK.)
FLIGHT PLAN- Specified information relating to
the intended flight of an aircraft that is filed orally or
in writing with an FSS or an ATC facility.
(See FAST FILE.)
(See FILED.)
(Refer to AIM.)
FLIGHT PLAN AREA- The geographical area
assigned by regional air traffic divisions to a flight
service station for the purpose of search and rescue
for VFR aircraft, issuance of NOTAMs, pilot
briefing, in‐flight services, broadcast, emergency
services, flight data processing, international opera‐
tions, and aviation weather services. Three letter
Pilot/Controller Glossary 2/14/08
PCG F-4
identifiers are assigned to every flight service station
and are annotated in AFDs and FAAO JO 7350.8,
LOCATION IDENTIFIERS, as tie‐in facilities.
(See FAST FILE.)
(See FILED.)
(Refer to AIM.)
FLIGHT RECORDER- A general term applied to
any instrument or device that records information
about the performance of an aircraft in flight or about
conditions encountered in flight. Flight recorders
may make records of airspeed, outside air
temperature, vertical acceleration, engine RPM,
manifold pressure, and other pertinent variables for a
given flight.
(See ICAO term FLIGHT RECORDER.)
FLIGHT RECORDER - Any type of
recorder installed in the aircraft for the purpose of
complementing accident/incident investigation.
Note:See Annex 6 Part I, for specifications relating
to flight recorders.
FLIGHT SERVICE STATION- Air traffic facilities
which provide pilot briefing, en route communica‐
tions and VFR search and rescue services, assist lost
aircraft and aircraft in emergency situations, relay
ATC clearances, originate Notices to Airmen,
broadcast aviation weather and NAS information,
and receive and process IFR flight plans. In addition,
at selected locations, FSSs provide En Route Flight
Advisory Service (Flight Watch), issue airport
advisories, and advise Customs and Immigration of
transborder flights. Selected Flight Service Stations
in Alaska also provide TWEB recordings and take
weather observations.
(Refer to AIM.)
FLIGHT STANDARDS DISTRICT OFFICE- An
FAA field office serving an assigned geographical
area and staffed with Flight Standards personnel who
serve the aviation industry and the general public on
matters relating to the certification and operation of
air carrier and general aviation aircraft. Activities
include general surveillance of operational safety,
certification of airmen and aircraft, accident
prevention, investigation, enforcement, etc.
FLIGHT TEST- A flight for the purpose of:
a. Investigating the operation/flight characteris‐
tics of an aircraft or aircraft component.
b. Evaluating an applicant for a pilot certificate or
rating.
FLIGHT VISIBILITY(See VISIBILITY.)
FLIGHT WATCH- A shortened term for use in
air‐ground contacts to identify the flight service
station providing En Route Flight Advisory Service;
e.g., “Oakland Flight Watch.”
(See EN ROUTE FLIGHT ADVISORY
SERVICE.)
FLIP(See DOD FLIP.)
FLY HEADING (DEGREES)- Informs the pilot of
the heading he/she should fly. The pilot may have to
turn to, or continue on, a specific compass direction
in order to comply with the instructions. The pilot is
expected to turn in the shorter direction to the heading
unless otherwise instructed by ATC.
FLY‐BY WAYPOINT- A fly‐by waypoint requires
the use of turn anticipation to avoid overshoot of the
next flight segment.
FLY‐OVER WAYPOINT- A fly‐over waypoint
precludes any turn until the waypoint is overflown
and is followed by an intercept maneuver of the next
flight segment.
FMA(See FINAL MONITOR AID.)
FMS(See FLIGHT MANAGEMENT SYSTEM.)
FMSP(See FLIGHT MANAGEMENT SYSTEM
PROCEDURE.)
FORMATION FLIGHT- More than one aircraft
which, by prior arrangement between the pilots,
operate as a single aircraft with regard to navigation
and position reporting. Separation between aircraft
within the formation is the responsibility of the flight
leader and the pilots of the other aircraft in the flight.
This includes transition periods when aircraft within
the formation are maneuvering to attain separation
from each other to effect individual control and
during join‐up and breakaway.
a. A standard form ation is one in which a
proximity of no more than 1 mile laterally or
longitudinally and within 100 feet vertically from the
flight leader is maintained by each wingman.
b. Nonstandard formations are those operating
under any of the following conditions:
Pilot/Controller Glossary 2/14/08
PCG F-5
1. When the flight leader has requested and ATC
has approved other than standard form ation
dimensions.
2. When operating within an authorized altitude
reservation (ALTRV) or under the provisions of a
letter of agreement.
3. When the operations are conducted in
airspace specifically designed for a special activity.
(See ALTITUDE RESERVATION.)
(Refer to 14 CFR Part 91.)
FRC(See REQUEST FULL ROUTE CLEARANCE.)
FREEZE/FROZEN- Terms used in referring to
arrivals which have been assigned ACLTs and to the
lists in which they are displayed.
FREEZE CALCULATED LANDING TIME- A
dynamic parameter number of minutes prior to the
meter fix calculated time of arrival for each aircraft
when the TCLT is frozen and becomes an ACLT (i.e.,
the VTA is updated and consequently the TCLT is
modified as appropriate until FCLT minutes prior to
meter fix calculated time of arrival, at which time
updating is suspended and an ACLT and a frozen
meter fix crossing time (MFT) is assigned).
FREEZE HORIZON- The time or point at which an
aircraft's STA becomes fixed and no longer fluctuates
with each radar update. This setting insures a constant
time for each aircraft, necessary for the metering
controller to plan his/her delay technique. This
setting can be either in distance from the meter fix or
a prescribed flying time to the meter fix.
FREEZE SPEED PARAMETER- A speed adapted
for each aircraft to determine fast and slow aircraft.
Fast aircraft freeze on parameter FCLT and slow
aircraft freeze on parameter MLDI.
FRICTION MEASUREMENT- A measurement of
the friction characteristics of the runway pavement
surface using continuous self‐watering friction
measurement equipment in accordance with the
specifications, procedures and schedules contained
in AC 150/5320-12, Measurement, Construction,
and Maintenance of Skid Resistant Airport Pavement
Surfaces.
FSDO(See FLIGHT STANDARDS DISTRICT OFFICE.)
FSPD(See FREEZE SPEED PARAMETER.)
FSS(See FLIGHT SERVICE STATION.)
FUEL DUMPING- Airborne release of usable fuel.
This does not include the dropping of fuel tanks.
(See JETTISONING OF EXTERNAL STORES.)
FUEL REMAINING- A phrase used by either pilots
or controllers when relating to the fuel remaining on
board until actual fuel exhaustion. When transmitting
such information in response to either a controller
question or pilot initiated cautionary advisory to air
traffic control, pilots will state the APPROXIMATE
NUMBER OF MINUTES the flight can continue
with the fuel remaining. All reserve fuel SHOULD
BE INCLUDED in the time stated, as should an
allowance for established fuel gauge system error.
FUEL SIPHONING- Unintentional release of fuel
caused by overflow, puncture, loose cap, etc.
FUEL VENTING(See FUEL SIPHONING.)
Pilot/Controller Glossary 2/14/08
PCG G-1
G
GATE HOLD PROCEDURES- Procedures at
selected airports to hold aircraft at the gate or other
ground location whenever departure delays exceed or
are anticipated to exceed 15 minutes. The sequence
for departure will be maintained in accordance with
initial call‐up unless modified by flow control
restrictions. Pilots should monitor the ground
control/clearance delivery frequency for engine
start/taxi advisories or new proposed start/taxi time
if the delay changes.
GBT(See GROUND-BASED TRANSCEIVER.)
GCA(See GROUND CONTROLLED APPROACH.)
GDP(See GROUND DELAY PROGRAM.)
GENERAL AVIATION- That portion of civil
aviation which encompasses all facets of aviation
except air carriers holding a certificate of public
convenience and necessity from the Civil Aeronau‐
tics Board and large aircraft commercial operators.
(See ICAO term GENERAL AVIATION.)
GENERAL AVIATION - All civil aviation
operations other than scheduled air services and
nonscheduled air transport operations for remunera‐
tion or hire.
GEO MAP- The digitized map markings associated
with the ASR‐9 Radar System.
GLIDEPATH(See GLIDESLOPE.)
GLIDEPATH - A descent profile determined
for vertical guidance during a final approach.
GLIDEPATH INTERCEPT ALTITUDE(See GLIDESLOPE INTERCEPT ALTITUDE.)
GLIDESLOPE- Provides vertical guidance for
aircraft during approach and landing. The glideslope/
glidepath is based on the following:
a. Electronic components emitting signals which
provide vertical guidance by reference to airborne
instruments during instrument approaches such as
ILS/MLS, or
b. Visual ground aids, such as VASI, which
provide vertical guidance for a VFR approach or for
the visual portion of an instrument approach and
landing.
c. PAR. Used by ATC to inform an aircraft making
a PAR approach of its vertical position (elevation)
relative to the descent profile.
(See ICAO term GLIDEPATH.)
GLIDESLOPE INTERCEPT ALTITUDE- The
minimum altitude to intercept the glideslope/path on
a precision approach. The intersection of the
published intercept altitude with the glideslope/path,
designated on Government charts by the lightning
bolt symbol, is the precision FAF; however, when the
approach chart shows an alternative lower glideslope
intercept altitude, and ATC directs a lower altitude,
the resultant lower intercept position is then the FAF.
(See FINAL APPROACH FIX.)
(See SEGMENTS OF AN INSTRUMENT
APPROACH PROCEDURE.)
GLOBAL POSITIONING SYSTEM (GPS)- A
space‐base radio positioning, navigation, and
time‐transfer system. The system provides highly
accurate position and velocity information, and
precise time, on a continuous global basis, to an
unlimited number of properly equipped users. The
system is unaffected by weather, and provides a
worldwide common grid reference system. The GPS
concept is predicated upon accurate and continuous
knowledge of the spatial position of each satellite in
the system with respect to time and distance from a
transmitting satellite to the user. The GPS receiver
automatically selects appropriate signals from the
satellites in view and translates these into three‐
dimensional position, velocity, and time. System
accuracy for civil users is normally 100 meters
horizontally.
GO AHEAD- Proceed with your message. Not to be
used for any other purpose.
GO AROUND- Instructions for a pilot to abandon
his/her approach to landing. Additional instructions
may follow. Unless otherwise advised by ATC, a
VFR aircraft or an aircraft conducting visual
approach should overfly the runway while climbing
to traffic pattern altitude and enter the traffic pattern
via the crosswind leg. A pilot on an IFR flight plan
Pilot/Controller Glossary 2/14/08
PCG G-2
making an instrument approach should execute the
published missed approach procedure or proceed as
instructed by ATC; e.g., “Go around” (additional
instructions if required).
(See LOW APPROACH.)
(See MISSED APPROACH.)
GPD(See GRAPHIC PLAN DISPLAY.)
GPS(See GLOBAL POSITIONING SYSTEM.)
GRAPHIC PLAN DIS PLAY (GPD)- A view
available with URET that provides a graphic display
of aircraft, traffic, and notification of predicted
conflicts. Graphic routes for Current Plans and Trial
Plans are displayed upon controller request.
(See USER REQUEST EVALUATION TOOL.)
GROUND-BASED TRANSCEIVER (GBT)- The
ground-based transmitter/receiver (transceiver) re‐
ceives automatic dependent surveillance-broadcast
messages, which are forwarded to an air traffic
control facility for processing and display with other
radar targets on the plan position indicator (radar
display).
(See AUTOMATIC DEPENDENT
SURVEILLANCE‐BROADCAST.)
GROUND CLUTTER- A pattern produced on the
radar scope by ground returns which may degrade
other radar returns in the affected area. The effect of
ground clutter is minimized by the use of moving
target indicator (MTI) circuits in the radar equipment
resulting in a radar presentation which displays only
targets which are in motion.
(See CLUTTER.)
GROUND COMMUNICATION OUTLET (GCO)-
An unstaffed, remotely controlled, ground/ground
communications facility. Pilots at uncontrolled
airports may contact ATC and FSS via VHF to a
telephone connection to obtain an instrument
clearance or close a VFR or IFR flight plan. They may
also get an updated weather briefing prior to takeoff.
Pilots will use four “key clicks” on the VHF radio to
contact the appropriate ATC facility or six “key
clicks” to contact the FSS. The GCO system is
intended to be used only on the ground.
GROUND CONTROLLED APPROACH- A radar
approach system operated from the ground by air
traffic control personnel transmitting instructions to
the pilot by radio. The approach may be conducted
with surveillance radar (ASR) only or with both
surveillance and precision approach radar (PAR).
Usage of the term “GCA” by pilots is discouraged
except when referring to a GCA facility. Pilots should
specifically request a “PAR” approach when a
precision radar approach is desired or request an
“ASR” or “surveillance” approach when a nonpreci‐
sion radar approach is desired.
(See RADAR APPROACH.)
GROUND DELAY PROGRAM (GDP)- A traffic
management process administered by the ATCSCC;
when aircraft are held on the ground. The purpose of
the program is to support the TM mission and limit
airborne holding. It is a flexible program and may be
implemented in various forms depending upon the
needs of the AT system. Ground delay programs
provide for equitable assignment of delays to all
system users.
GROUND SPEED- The speed of an aircraft relative
to the surface of the earth.
GROUND STOP (GS)- The GS is a process that
requires aircraft that meet a specific criteria to remain
on the ground. The criteria may be airport specific,
airspace specific, or equipment specific; for example,
all departures to San Francisco, or all departures
entering Yorktown sector, or all Category I and II
aircraft going to Charlotte. GSs normally occur with
little or no warning.
GROUND VISIBILITY(See VISIBILITY.)
GS(See GROUND STOP.)
Pilot/Controller Glossary 2/14/08
PCG H-1
H
HAA(See HEIGHT ABOVE AIRPORT.)
HAL(See HEIGHT ABOVE LANDING.)
HANDOFF- An action taken to transfer the radar
identification of an aircraft from one controller to
another if the aircraft will enter the receiving
controller's airspace and radio communications with
the aircraft will be transferred.
HAR(See HIGH ALTITUDE REDESIGN.)
HAT(See HEIGHT ABOVE TOUCHDOWN.)
HAVE NUMBERS- Used by pilots to inform ATC
that they have received runway, wind, and altimeter
information only.
HAZARDOUS INFLIGHT WEATHER ADVISO‐
RY SERVICE- Continuous recorded hazardous
inflight weather forecasts broadcasted to airborne
pilots over selected VOR outlets defined as an
HIWAS BROADCAST AREA.
HAZARDOUS WEATHER INFORMATION-
Summary of significant meteorological information
(SIGMET/WS), convective significant meteorologi‐
cal information (convective SIGMET/WST), urgent
pilot weather reports (urgent PIREP/UUA), center
weather advisories (CWA), airmen's meteorological
information (AIRMET/WA) and any other weather
such as isolated thunderstorms that are rapidly
developing and increasing in intensity, or low
ceilings and visibilities that are becoming wide‐
spread which is considered significant and are not
included in a current hazardous weather advisory.
HEAVY (AIRCRAFT)-
(See AIRCRAFT CLASSES.)
HEIGHT ABOVE AIRPORT- The height of the
Minimum Descent Altitude above the published
airport elevation. This is published in conjunction
with circling minimums.
(See MINIMUM DESCENT ALTITUDE.)
HEIGHT ABOVE LANDING- The height above a
designated helicopter landing area used for helicopter
instrument approach procedures.
(Refer to 14 CFR Part 97.)
HEIGHT ABOVE TOUCHDOWN- The height of
the Decision Height or Minimum Descent Altitude
above the highest runway elevation in the touchdown
zone (first 3,000 feet of the runway). HAT is
published on instrument approach charts in conjunc‐
tion with all straight‐in minimums.
(See DECISION HEIGHT.)
(See MINIMUM DESCENT ALTITUDE.)
HELICOPTER- Rotorcraft that, for its horizontal
motion, depends principally on its engine‐driven
rotors.
(See ICAO term HELICOPTER.)
HELICOPTER - A heavier‐than‐air aircraft
supported in flight chiefly by the reactions of the air
on one or more power‐driven rotors on substantially
vertical axes.
HELIPAD- A small, designated area, usually with a
prepared surface, on a heliport, airport, landing/take‐
off area, apron/ramp, or movement area used for
takeoff, landing, or parking of helicopters.
HELIPORT- An area of land, water, or structure used
or intended to be used for the landing and takeoff of
helicopters and includes its buildings and facilities if
any.
HELIPORT REFERENCE POINT (HRP)- The
geographic center of a heliport.
HERTZ- The standard radio equivalent of frequency
in cycles per second of an electromagnetic wave.
Kilohertz (kHz) is a frequency of one thousand cycles
per second. Megahertz (MHz) is a frequency of one
million cycles per second.
HF(See HIGH FREQUENCY.)
HF COMMUNICATIONS(See HIGH FREQUENCY COMMUNICATIONS.)
HIGH ALTITUDE REDESIGN (HAR)- A level of
non-restrictive routing (NRR) service for aircraft
that have all waypoints associated with the HAR
program in their flight management systems or
RNAV equipage.
Pilot/Controller Glossary 2/14/08
PCG H-2
HIGH FREQUENCY- The frequency band between
3 and 30 MHz.
(See HIGH FREQUENCY COMMUNICATIONS.)
HIGH FREQUENCY COMMUNICATIONS- High
radio frequencies (HF) between 3 and 30 MHz used
for air‐to‐ground voice communication in overseas
operations.
HIGH SPEED EXIT(See HIGH SPEED TAXIWAY.)
HIGH SPEED TAXIWAY- A long radius taxiway
designed and provided with lighting or marking to
define the path of aircraft, traveling at high speed (up
to 60 knots), from the runway center to a point on the
center of a taxiway. Also referred to as long radius
exit or turn‐off taxiway. The high speed taxiway is
designed to expedite aircraft turning off the runway
after landing, thus reducing runway occupancy time.
HIGH SPEED TURNOFF(See HIGH SPEED TAXIWAY.)
HIWAS(See HAZARDOUS INFLIGHT WEATHER
ADVISORY SERVICE.)
HIWAS AREA(See HAZARDOUS INFLIGHT WEATHER
ADVISORY SERVICE.)
HIWAS BROADCAST AREA- A geographical area
of responsibility including one or more HIWAS
outlet areas assigned to an AFSS/FSS for hazardous
weather advisory broadcasting.
HIWAS OUTLET AREA- An area defined as a 150
NM radius of a HIWAS outlet, expanded as necessary
to provide coverage.
HOLD FOR RELEASE- Used by ATC to delay an
aircraft for traffic management reasons; i.e., weather,
traffic volume, etc. Hold for release instructions
(including departure delay information) are used to
inform a pilot or a controller (either directly or
through an authorized relay) that an IFR departure
clearance is not valid until a release time or additional
instructions have been received.
(See ICAO term HOLDING POINT.)
HOLD IN LIEU OF PROCEDURE TURN- A hold
in lieu of procedure turn shall be established over a
final or intermediate fix when an approach can be
made from a properly aligned holding pattern. The
hold in lieu of procedure turn permits the pilot to
align with the final or intermediate segment of the
approach and/or descend in the holding pattern to an
altitude that will permit a normal descent to the final
approach fix altitude. The hold in lieu of procedure
turn is a required maneuver (the same as a procedure
turn) unless the aircraft is being radar vectored to the
final approach course, when “NoPT” is shown on the
approach chart, or when the pilot requests or the
controller advises the pilot to make a “straight-in”
approach.
HOLD PROCEDURE- A predetermined maneuver
which keeps aircraft within a specified airspace while
awaiting further clearance from air traffic control.
Also used during ground operations to keep aircraft
within a specified area or at a specified point while
awaiting further clearance from air traffic control.
(See HOLDING FIX.)
(Refer to AIM.)
HOLDING FIX- A specified fix identifiable to a
pilot by NAVAIDs or visual reference to the ground
used as a reference point in establishing and
maintaining the position of an aircraft while holding.
(See FIX.)
(See VISUAL HOLDING.)
(Refer to AIM.)
HOLDING POINT - A specified location,
identified by visual or other means, in the vicinity of
which the position of an aircraft in flight is
maintained in accordance with air traffic control
clearances.
HOLDING PROCEDURE(See HOLD PROCEDURE.)
HOLD‐SHORT POINT- A point on the runway
beyond which a landing aircraft with a LAHSO
clearance is not authorized to proceed. This point
may be located prior to an intersecting runway,
taxiway, predetermined point, or approach/departure
flight path.
HOLD‐SHORT POSITION LIGHTS- Flashing
in‐pavement white lights located at specified
hold‐short points.
HOLD‐SHORT POSITION MARKING- The
painted runway marking located at the hold‐short
point on all LAHSO runways.
HOLD‐SHORT POSITION SIGNS- Red and white
holding position signs located alongside the
hold‐short point.
Pilot/Controller Glossary 2/14/08
PCG H-3
HOMING- Flight toward a NAVAID, without
correcting for wind, by adjusting the aircraft heading
to maintain a relative bearing of zero degrees.
(See BEARING.)
(See ICAO term HOMING.)
HOMING - The procedure of using the
direction‐finding equipment of one radio station with
the emission of another radio station, where at least
one of the stations is mobile, and whereby the mobile
station proceeds continuously towards the other
station.
HOVER CHECK- Used to describe when a
helicopter/VTOL aircraft requires a stabilized hover
to conduct a performance/power check prior to hover
taxi, air taxi, or takeoff. Altitude of the hover will
vary based on the purpose of the check.
HOVER TAXI- Used to describe a helicopter/VTOL
aircraft movement conducted above the surface and
in ground effect at airspeeds less than approximately
20 knots. The actual height may vary, and some
helicopters may require hover taxi above 25 feet AGL
to reduce ground effect turbulence or provide
clearance for cargo slingloads.
(See AIR TAXI.)
(See HOVER CHECK.)
(Refer to AIM.)
HOW DO YOU HEAR ME?- A question relating to
the quality of the transmission or to determine how
well the transmission is being received.
HZ(See HERTZ.)
Pilot/Controller Glossary 2/14/08
PCG I-1
I
I SAY AGAIN- The message will be repeated.
IAF(See INITIAL APPROACH FIX.)
IAP(See INSTRUMENT APPROACH
PROCEDURE.)
IAWP- Initial Approach Waypoint
ICAO(See ICAO Term INTERNATIONAL CIVIL
AVIATION ORGANIZATION.)
ICING- The accumulation of airframe ice.
Types of icing are:
a. Rime Ice- Rough, milky, opaque ice formed by
the instantaneous freezing of small supercooled
water droplets.
b. Clear Ice- A glossy, clear, or translucent ice
formed by the relatively slow freezing or large
supercooled water droplets.
c. Mixed- A mixture of clear ice and rime ice.
Intensity of icing:
a. Trace- Ice becomes perceptible. Rate of
accumulation is slightly greater than the rate of
sublimation. Deicing/anti‐icing equipment is not
utilized unless encountered for an extended period of
time (over 1 hour).
b. Light- The rate of accumulation may create a
problem if flight is prolonged in this environment
(over 1 hour). Occasional use of deicing/anti‐icing
equipment removes/prevents accumulation. It does
not present a problem if the deicing/anti‐icing
equipment is used.
c. Moderate- The rate of accumulation is such that
even short encounters become potentially hazardous
and use of deicing/anti‐icing equipment or flight
diversion is necessary.
d. Severe- The rate of accumulation is such that
deicing/anti‐icing equipment fails to reduce or
control the hazard. Immediate flight diversion is
necessary.
IDENT- A request for a pilot to activate the aircraft
transponder identification feature. This will help the
controller to confirm an aircraft identity or to identify
an aircraft.
(Refer to AIM.)
IDENT FEATURE- The special feature in the Air
Traffic Control Radar Beacon System (ATCRBS)
equipment. It is used to immediately distinguish one
displayed beacon target from other beacon targets.
(See IDENT.)
IF(See INTERMEDIATE FIX.)
IFIM(See INTERNATIONAL FLIGHT INFORMATION
MANUAL.)
IF NO TRANSMISSION RECEIVED FOR
(TIME)- Used by ATC in radar approaches to prefix
procedures which should be followed by the pilot in
event of lost communications.
(See LOST COMMUNICATIONS.)
IFR(See INSTRUMENT FLIGHT RULES.)
IFR AIRCRAFT- An aircraft conducting flight in
accordance with instrument flight rules.
IFR CONDITIONS- Weather conditions below the
minimum for flight under visual flight rules.
(See INSTRUMENT METEOROLOGICAL
CONDITIONS.)
IFR DEPARTURE PROCEDURE(See IFR TAKEOFF MINIMUMS AND
DEPARTURE PROCEDURES.)
(Refer to AIM.)
IFR FLIGHT(See IFR AIRCRAFT.)
IFR LANDING MINIMUMS(See LANDING MINIMUMS.)
IFR MILITARY TRAINING ROUTES (IR)- 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 in both IFR and VFR weather conditions
below 10,000 feet MSL at airspeeds in excess of 250
knots IAS.
IFR TAKEOFF MINIMUMS AND DEPARTURE
PROCEDURES- Title 14 Code of Federal
Pilot/Controller Glossary 2/14/08
PCG I-2
Regulations Part 91, prescribes standard takeoff rules
for certain civil users. At some airports, obstructions
or other factors require the establishm ent of
nonstandard takeoff minimums, departure proce‐
dures, or both to assist pilots in avoiding obstacles
during climb to the minimum en route altitude. Those
airports are listed in FAA/DOD Instrument Approach
Procedures (IAPs) Charts under a section entitled
“IFR Takeoff Minimums and Departure Procedures.”
The FAA/DOD IAP chart legend illustrates the
symbol used to alert the pilot to nonstandard takeoff
minimums and departure procedures. When depart‐
ing IFR from such airports or from any airports where
there are no departure procedures, DPs, or ATC
facilities available, pilots should advise ATC of any
departure limitations. Controllers may query a pilot
to determine acceptable departure directions, turns,
or headings after takeoff. Pilots should be familiar
with the departure procedures and must assure that
their aircraft can meet or exceed any specified climb
gradients.
IF/IAWP- Intermediate Fix/Initial Approach Way‐
point. The waypoint where the final approach course
of a T approach meets the crossbar of the T. When
designated (in conjunction with a TAA) this
waypoint will be used as an IAWP when approaching
the airport from certain directions, and as an IFWP
when beginning the approach from another IAWP.
IFWP- Intermediate Fix Waypoint
ILS(See INSTRUMENT LANDING SYSTEM.)
ILS CATEGORIES- 1. ILS Category I. An ILS
approach procedure which provides for approach to
a height above touchdown of not less than 200 feet
and with runway visual range of not less than 1,800
feet.- 2. ILS Category II. An ILS approach procedure
which provides for approach to a height above
touchdown of not less than 100 feet and with runway
visual range of not less than 1,200 feet.- 3. ILS
Category III:
a. IIIA.-An ILS approach procedure which
provides for approach without a decision height
minimum and with runway visual range of not less
than 700 feet.
b. IIIB.-An ILS approach procedure which
provides for approach without a decision height
minimum and with runway visual range of not less
than 150 feet.
c. IIIC.-An ILS approach procedure which
provides for approach without a decision height
minimum and without runway visual range
minimum.
ILS PRM APPROACH- An instrument landing
system (ILS) approach conducted to parallel runways
whose extended centerlines are separated by less than
4,300 feet and the parallel runways have a Precision
Runway Monitoring (PRM) system that permits
simultaneous independent ILS approaches.
IM(See INNER MARKER.)
IMC(See INSTRUMENT METEOROLOGICAL
CONDITIONS.)
IMMEDIATELY- Used by ATC or pilots when such
action compliance is required to avoid an imminent
situation.
INCERFA (Uncertainty Phase) - A situation
wherein uncertainty exists as to the safety of an
aircraft and its occupants.
INCREASE SPEED TO (SPEED)-
(See SPEED ADJUSTMENT.)
INERTIAL NAVIGATION SYSTEM- An RNAV
system which is a form of self‐contained navigation.
(See Area Navigation/RNAV.)
INFLIGHT REFUELING(See AERIAL REFUELING.)
INFLIGHT WEATHER ADVISORY(See WEATHER ADVISORY.)
INFORMATION REQUEST- A request originated
by an FSS for information concerning an overdue
VFR aircraft.
INITIAL APPROACH FIX- The fixes depicted on
instrument approach procedure charts that identify
the beginning of the initial approach segment(s).
(See FIX.)
(See SEGMENTS OF AN INSTRUMENT
APPROACH PROCEDURE.)
INITIAL APPROACH SEGMENT(See SEGMENTS OF AN INSTRUMENT
APPROACH PROCEDURE.)
INITIAL APPROACH SEGMENT - That
segment of an instrument approach procedure
between the initial approach fix and the intermediate
approach fix or, where applicable, the final approach
fix or point.
Pilot/Controller Glossary 2/14/08
PCG I-3
INLAND NAVIGATION FACILITY- A navigation
aid on a North American Route at which the common
route and/or the noncommon route begins or ends.
INNER MARKER- A marker beacon used with an
ILS (CAT II) precision approach located between the
middle marker and the end of the ILS runway,
transmitting a radiation pattern keyed at six dots per
second and indicating to the pilot, both aurally and
visually, that he/she is at the designated decision
height (DH), normally 100 feet above the touchdown
zone elevation, on the ILS CAT II approach. It also
marks progress during a CAT III approach.
(See INSTRUMENT LANDING SYSTEM.)
(Refer to AIM.)
INNER MARKER BEACON(See INNER MARKER.)
INREQ(See INFORMATION REQUEST.)
INS(See INERTIAL NAVIGATION SYSTEM.)
INSTRUMENT APPROACH(See INSTRUMENT APPROACH
PROCEDURE.)
INSTRUMENT APPROACH PROCEDURE- A
series of predetermined maneuvers for the orderly
transfer of an aircraft under instrument flight
conditions from the beginning of the initial approach
to a landing or to a point from which a landing may
be made visually. It is prescribed and approved for a
specific airport by competent authority.
(See SEGMENTS OF AN INSTRUMENT
APPROACH PROCEDURE.)
(Refer to 14 CFR Part 91.)
(Refer to AIM.)
a. U.S. civil standard instrument approach
procedures are approved by the FAA as prescribed
under 14 CFR Part 97 and are available for public
use.
b. U.S. military standard instrument approach
procedures are approved and published by the
Department of Defense.
c. Special instrument approach procedures are
approved by the FAA for individual operators but are
not published in 14 CFR Part 97 for public use.
(See ICAO term INSTRUMENT APPROACH
PROCEDURE.)
INSTRUMENT APPROACH PROCEDURE
- A series of predetermined maneuvers by
reference to flight instruments with specified
protection from obstacles from the initial approach
fix, or where applicable, from the beginning of a
defined arrival route to a point from which a landing
can be completed and thereafter, if a landing is not
completed, to a position at which holding or en route
obstacle clearance criteria apply.
INSTRUMENT APPROACH PROCEDURES
CHARTS(See AERONAUTICAL CHART.)
INSTRUMENT DEPARTURE PROCEDURE
(DP)- A preplanned instrument flight rule (IFR)
departure procedure published for pilot use, in
graphic or textual format, that provides obstruction
clearance from the terminal area to the appropriate en
route structure. There are two types of DP, Obstacle
Departure Procedure (ODP), printed either textually
or graphically, and, Standard Instrument Departure
(SID), which is always printed graphically.
(See IFR TAKEOFF MINIMUMS AND
DEPARTURE PROCEDURES.)
(See OBSTACLE DEPARTURE PROCEDURES.)
(See STANDARD INSTRUMENT DEPARTURES.)
(Refer to AIM.)
INSTRUMENT DEPARTURE PROCEDURE (DP)
CHARTS(See AERONAUTICAL CHART.)
INSTRUMENT FLIGHT RULES- Rules governing
the procedures for conducting instrument flight. Also
a term used by pilots and controllers to indicate type
of flight plan.
(See INSTRUMENT METEOROLOGICAL
CONDITIONS.)
(See VISUAL FLIGHT RULES.)
(See VISUAL METEOROLOGICAL
CONDITIONS.)
(See ICAO term INSTRUMENT FLIGHT
RULES.)
(Refer to AIM.)
INSTRUMENT FLIGHT RULES - A set of
rules governing the conduct of flight under
instrument meteorological conditions.
INSTRUMENT LANDING SYSTEM- A precision
instrument approach system which normally consists
of the following electronic components and visual
aids:
Pilot/Controller Glossary 2/14/08
PCG I-4
a. Localizer.
(See LOCALIZER.)
b. Glideslope.
(See GLIDESLOPE.)
c. Outer Marker.
(See OUTER MARKER.)
d. Middle Marker.
(See MIDDLE MARKER.)
e. Approach Lights.
(See AIRPORT LIGHTING.)
(Refer to 14 CFR Part 91.)
(Refer to AIM.)
INSTRUMENT METEOROLOGICAL CONDI‐
TIONS- Meteorological conditions expressed in
terms of visibility, distance from cloud, and ceiling
less than the minima specified for visual meteorolog‐
ical conditions.
(See INSTRUMENT FLIGHT RULES.)
(See VISUAL FLIGHT RULES.)
(See VISUAL METEOROLOGICAL
CONDITIONS.)
INSTRUMENT RUNWAY- A runway equipped
with electronic and visual navigation aids for which
a precision or nonprecision approach procedure
having straight‐in landing minimums has been
approved.
(See ICAO term INSTRUMENT RUNWAY.)
INSTRUMENT RUNWAY - One of the
following types of runways intended for the
operation of aircraft using instrument approach
procedures:
a. Nonprecision Approach Runway-An instru‐
ment runway served by visual aids and a nonvisual
aid providing at least directional guidance adequate
for a straight‐in approach.
b. Precision Approach Runway, Category I-An
instrument runway served by ILS and visual aids
intended for operations down to 60 m (200 feet)
decision height and down to an RVR of the order of
800 m.
c. Precision Approach Runway, Category II-An
instrument runway served by ILS and visual aids
intended for operations down to 30 m (100 feet)
decision height and down to an RVR of the order of
400 m.
d. Precision Approach Runway, Category III-An
instrument runway served by ILS to and along the
surface of the runway and:
1. Intended for operations down to an RVR of
the order of 200 m (no decision height being
applicable) using visual aids during the final phase of
landing;
2. Intended for operations down to an RVR of
the order of 50 m (no decision height being
applicable) using visual aids for taxiing;
3. Intended for operations without reliance on
visual reference for landing or taxiing.
Note 1:See Annex 10 Volume I, Part I, Chapter 3,
for related ILS specifications.
Note 2:Visual aids need not necessarily be
matched to the scale of nonvisual aids provided.
The criterion for the selection of visual aids is the
conditions in which operations are intended to be
conducted.
INTEGRITY- The ability of a system to provide
timely warnings to users when the system should not
be used for navigation.
INTERMEDIATE APPROACH SEGMENT(See SEGMENTS OF AN INSTRUMENT
APPROACH PROCEDURE.)
INTERMEDIATE APPROACH SEGMENT
- That segment of an instrument approach
procedure between either the intermediate approach
fix and the final approach fix or point, or between the
end of a reversal, race track or dead reckoning track
procedure and the final approach fix or point, as
appropriate.
INTERMEDIATE FIX- The fix that identifies the
beginning of the intermediate approach segment of an
instrument approach procedure. The fix is not
normally identified on the instrument approach chart
as an intermediate fix (IF).
(See SEGMENTS OF AN INSTRUMENT
APPROACH PROCEDURE.)
INTERMEDIATE LANDING- On the rare occasion
that this option is requested, it should be approved.
The departure center, however, must advise the
ATCSCC so that the appropriate delay is carried over
and assigned at the interm ediate airport. An
intermediate landing airport within the arrival center
will not be accepted without coordination with and
the approval of the ATCSCC.
INTERNATIONAL AIRPORT- Relating to interna‐
tional flight, it means:
Pilot/Controller Glossary 2/14/08
PCG I-5
a. An airport of entry which has been designated
by the Secretary of Treasury or Commissioner of
Customs as an international airport for customs
service.
b. A landing rights airport at which specific
permission to land must be obtained from customs
authorities in advance of contemplated use.
c. Airports designated under the Convention on
International Civil Aviation as an airport for use by
international commercial air transport and/or interna‐
tional general aviation.
(See ICAO term INTERNATIONAL AIRPORT.)
(Refer to AIRPORT/FACILITY DIRECTORY.)
(Refer to IFIM.)
INTERNATIONAL AIRPORT - Any airport
designated by the Contracting State in whose
territory it is situated as an airport of entry and
departure for international air traffic, where the
formalities incident to customs, immigration, public
health, animal and plant quarantine and similar
procedures are carried out.
INTERNATIONAL CIVIL AVIATION ORGA‐
NIZATION - A specialized agency of the
United Nations whose objective is to develop the
principles and techniques of international air
navigation and to foster planning and development of
international civil air transport.
a. Regions include:
1. African‐Indian Ocean Region
2. Caribbean Region
3. European Region
4. Middle East/Asia Region
5. North American Region
6. North Atlantic Region
7. Pacific Region
8. South American Region
INTERNATIONAL FLIGHT INFORMATION
MANUAL- A publication designed primarily as a
pilot's preflight planning guide for flights into
foreign airspace and for flights returning to the U.S.
from foreign locations.
INTERROGATOR- The ground‐based surveillance
radar beacon transmitter‐receiver, which normally
scans in synchronism with a prim ary radar,
transmitting discrete radio signals which repetitious‐
ly request all transponders on the mode being used to
reply. The replies received are mixed with the
primary radar returns and displayed on the same plan
position indicator (radar scope). Also, applied to the
airborne element of the TACAN/DME system.
(See TRANSPONDER.)
(Refer to AIM.)
INTERSECTING RUNWAYS- Two or more
runways which cross or meet within their lengths.
(See INTERSECTION.)
INTERSECTIONa. A point defined by any combination of courses,
radials, or bearings of two or more navigational aids.
b. Used to describe the point where two runways,
a runway and a taxiway, or two taxiways cross or
meet.
INTERSECTION DEPARTURE- A departure from
any runway intersection except the end of the runway.
(See INTERSECTION.)
INTERSECTION TAKEOFF(See INTERSECTION DEPARTURE.)
IR(See IFR MILITARY TRAINING ROUTES.)
Pilot/Controller Glossary 2/14/08
PCG J-1
J
JAMMING- Electronic or mechanical interference
which may disrupt the display of aircraft on radar or
the transmission/reception of radio communications/
navigation.
JET BLAST- Jet engine exhaust (thrust stream
turbulence).
(See WAKE TURBULENCE.)
JET ROUTE- A route designed to serve aircraft
operations from 18,000 feet MSL up to and including
flight level 450. The routes are referred to as “J”
routes with numbering to identify the designated
route; e.g., J105.
(See Class A AIRSPACE.)
(Refer to 14 CFR Part 71.)
JET STREAM- A migrating stream of high‐speed
winds present at high altitudes.
JETTISONING OF EXTERNAL STORES- Air‐
borne release of external stores; e.g., tiptanks,
ordnance.
(See FUEL DUMPING.)
(Refer to 14 CFR Part 91.)
JOINT USE RESTRICTED AREA(See RESTRICTED AREA.)
Pilot/Controller Glossary 2/14/08
PCG K-1
K
KNOWN TRAFFIC- With respect to ATC clear‐
ances, means aircraft whose altitude, position, and
intentions are known to ATC.
Pilot/Controller Glossary 2/14/08
PCG L-1
L
LAA(See LOCAL AIRPORT ADVISORY.)
LAAS(See LOW ALTITUDE ALERT SYSTEM.)
LAHSO- An acronym for “Land and Hold Short
Operation.” These operations include landing and
holding short of an intersecting runway, a taxiway, a
predetermined point, or an approach/departure
flightpath.
LAHSO‐DRY- Land and hold short operations on
runways that are dry.
LAHSO‐WET- Land and hold short operations on
runways that are wet (but not contaminated).
LAND AND HOLD SHORT OPERATIONS -
Operations which include simultaneous takeoffs and
landings and/or simultaneous landings when a
landing aircraft is able and is instructed by the
controller to hold‐short of the intersecting runway/
taxiway or designated hold‐short point. Pilots are
expected to promptly inform the controller if the hold
short clearance cannot be accepted.
(See PARALLEL RUNWAYS.)
(Refer to AIM.)
LANDING AREA- Any locality either on land,
water, or structures, including airports/heliports and
intermediate landing fields, which is used, or
intended to be used, for the landing and takeoff of
aircraft whether or not facilities are provided for the
shelter, servicing, or for receiving or discharging
passengers or cargo.
(See ICAO term LANDING AREA.)
LANDING AREA - That part of a movement
area intended for the landing or take‐off of aircraft.
LANDING DIRECTION INDICATOR- A device
which visually indicates the direction in which
landings and takeoffs should be made.
(See TETRAHEDRON.)
(Refer to AIM.)
LANDING DISTANCE AVAILABLE - The
length of runway which is declared available and
suitable for the ground run of an aeroplane landing.
LANDING MINIMUMS- The minimum visibility
prescribed for landing a civil aircraft while using an
instrument approach procedure. The minimum
applies with other limitations set forth in 14 CFR
Part 91 with respect to the Minimum Descent
Altitude (MDA) or Decision Height (DH) prescribed
in the instrument approach procedures as follows:
a. Straight‐in landing minimums. A statement of
MDA and visibility, or DH and visibility, required for
a straight‐in landing on a specified runway, or
b. Circling minimums. A statement of MDA and
visibility required for the circle‐to‐land maneuver.
Note:Descent below the established MDA or DH is
not authorized during an approach unless the
aircraft is in a position from which a normal
approach to the runway of intended landing can be
made and adequate visual reference to required
visual cues is maintained.
(See CIRCLE‐TO‐LAND MANEUVER.)
(See DECISION HEIGHT.)
(See INSTRUMENT APPROACH
PROCEDURE.)
(See MINIMUM DESCENT ALTITUDE.)
(See STRAIGHT‐IN LANDING.)
(See VISIBILITY.)
(Refer to 14 CFR Part 91.)
LANDING ROLL- The distance from the point of
touchdown to the point where the aircraft can be
brought to a stop or exit the runway.
LANDING SEQUENCE- The order in which
aircraft are positioned for landing.
(See APPROACH SEQUENCE.)
LAST ASSIGNED ALTITUDE- The last altitude/
flight level assigned by ATC and acknowledged by
the pilot.
(See MAINTAIN.)
(Refer to 14 CFR Part 91.)
LATERAL NAVIGATION (LNAV)– A function of
area navigation (RNAV) equipment which calculates,
displays, and provides lateral guidance to a profile or
path.
LATERAL SEPARATION- The lateral spacing of
aircraft at the same altitude by requiring operation on
different routes or in different geographical locations.
(See SEPARATION.)
Pilot/Controller Glossary 2/14/08
PCG L-2
LDA(See LOCALIZER TYPE DIRECTIONAL AID.)
(See ICAO Term LANDING DISTANCE
AVAILABLE.)
LF(See LOW FREQUENCY.)
LIGHTED AIRPORT- An airport where runway and
obstruction lighting is available.
(See AIRPORT LIGHTING.)
(Refer to AIM.)
LIGHT GUN- A handheld directional light signaling
device which emits a brilliant narrow beam of white,
green, or red light as selected by the tower controller.
The color and type of light transmitted can be used to
approve or disapprove anticipated pilot actions where
radio communication is not available. The light gun
is used for controlling traffic operating in the vicinity
of the airport and on the airport movement area.
(Refer to AIM.)
LOCAL AIRPORT ADVISORY (LAA)- A service
provided by facilities, which are located on the
landing airport, have a discrete ground-to-air
communication frequency or the tower frequency
when the tower is closed, automated weather
reporting with voice broadcasting, and a continuous
ASOS/AWOS data display, other continuous direct
reading instruments, or manual observations avail‐
able to the specialist.
(See AIRPORT ADVISORY AREA.)
LOCAL TRAFFIC- Aircraft operating in the traffic
pattern or within sight of the tower, or aircraft known
to be departing or arriving from flight in local practice
areas, or aircraft executing practice instrument
approaches at the airport.
(See TRAFFIC PATTERN.)
LOCALIZER- The component of an ILS which
provides course guidance to the runway.
(See INSTRUMENT LANDING SYSTEM.)
(See ICAO term LOCALIZER COURSE.)
(Refer to AIM.)
LOCALIZER COURSE - The locus of
points, in any given horizontal plane, at which the
DDM (difference in depth of modulation) is zero.
LOCALIZER OFFSET- An angular offset of the
localizer from the runway extended centerline in a
direction away from the no transgression zone (NTZ)
that increases the normal operating zone (NOZ)
width. An offset requires a 50 foot increase in DH and
is not authorized for CAT II and CAT III approaches.
LOCALIZER TYPE DIRECTIONAL AID- A
NAVAID used for nonprecision instrument ap‐
proaches with utility and accuracy comparable to a
localizer but which is not a part of a complete ILS and
is not aligned with the runway.
(Refer to AIM.)
LOCALIZER USABLE DISTANCE- The maxi‐
mum distance from the localizer transmitter at a
specified altitude, as verified by flight inspection, at
which reliable course information is continuously
received.
(Refer to AIM.)
LOCATOR - An LM/MF NDB used as an aid
to final approach.
Note:A locator usually has an average radius of
rated coverage of between 18.5 and 46.3 km (10
and 25 NM).
LONG RANGE NAVIGATION(See LORAN.)
LONGITUDINAL SEPARATION- The longitudi‐
nal spacing of aircraft at the same altitude by a
minimum distance expressed in units of time or
miles.
(See SEPARATION.)
(Refer to AIM.)
LORAN- An electronic navigational system by
which hyperbolic lines of position are determined by
measuring the difference in the time of reception of
synchronized pulse signals from two fixed transmit‐
ters. Loran A operates in the 1750‐1950 kHz
frequency band. Loran C and D operate in the
100‐110 kHz frequency band.
(Refer to AIM.)
LOST COMMUNICATIONS- Loss of the ability to
communicate by radio. Aircraft are sometimes
referred to as NORDO (No Radio). Standard pilot
procedures are specified in 14 CFR Part 91. Radar
controllers issue procedures for pilots to follow in the
event of lost communications during a radar approach
when weather reports indicate that an aircraft will
likely encounter IFR weather conditions during the
approach.
(Refer to 14 CFR Part 91.)
(Refer AIM.)
Pilot/Controller Glossary 2/14/08
PCG L-3
LOW ALTITUDE AIRWAY STRUCTURE- The
network of airways serving aircraft operations up to
but not including 18,000 feet MSL.
(See AIRWAY.)
(Refer to AIM.)
LOW ALTITUDE ALERT, CHECK YOUR ALTI‐
TUDE IMMEDIATELY(See SAFETY ALERT.)
LOW ALTITUDE ALERT SYSTEM- An auto‐
mated function of the TPX‐42 that alerts the
controller when a Mode C transponder equipped
aircraft on an IFR flight plan is below a
predetermined minimum safe altitude. If requested
by the pilot, Low Altitude Alert System monitoring
is also available to VFR Mode C transponder
equipped aircraft.
LOW APPROACH- An approach over an airport or
runway following an instrument approach or a VFR
approach including the go‐around maneuver where
the pilot intentionally does not make contact with the
runway.
(Refer to AIM.)
LOW FREQUENCY- The frequency band between
30 and 300 kHz.
(Refer to AIM.)
LPV- A type of approach with vertical guidance
(APV) based on WAAS, published on RNAV (GPS)
approach charts. This procedure takes advantage of
the precise lateral guidance available from WAAS.
The minima is published as a decision altitude (DA).
Pilot/Controller Glossary 2/14/08
PCG M-1
M
MAA(See MAXIMUM AUTHORIZED ALTITUDE.)
MACH NUMBER- The ratio of true airspeed to the
speed of sound; e.g., MACH .82, MACH 1.6.
(See AIRSPEED.)
MACH TECHNIQUE - Describes a control
technique used by air traffic control whereby turbojet
aircraft operating successively along suitable routes
are cleared to maintain appropriate MACH numbers
for a relevant portion of the en route phase of flight.
The principle objective is to achieve improved
utilization of the airspace and to ensure that
separation between successive aircraft does not
decrease below the established minima.
MAHWP- Missed Approach Holding Waypoint
MAINTAINa. Concerning altitude/flight level, the term
means to remain at the altitude/flight level specified.
The phrase “climb and” or “descend and” normally
precedes “maintain” and the altitude assignment;
e.g., “descend and maintain 5,000.”
b. Concerning other ATC instructions, the term is
used in its literal sense; e.g., maintain VFR.
MAINTENANCE PLANNING FRICTION
LEVEL- The friction level specified in
AC 150/5320‐12, Measurement, Construction, and
Maintenance of Skid Resistant Airport Pavement
Surfaces, which represents the friction value below
which the runway pavem ent surface rem ains
acceptable for any category or class of aircraft
operations but which is beginning to show signs of
deterioration. This value will vary depending on the
particular friction measurement equipment used.
MAKE SHORT APPROACH- Used by ATC to
inform a pilot to alter his/her traffic pattern so as to
make a short final approach.
(See TRAFFIC PATTERN.)
MAN PORTABLE AIR DEFENSE SYSTEMS
(MANPADS)- MANPADS are lightweight, shoul‐
der-launched, missile systems used to bring down
aircraft and create mass casualties. The potential for
MANPADS use against airborne aircraft is real and
requires familiarity with the subject. Terrorists
choose MANPADS because the weapons are low
cost, highly mobile, require minimal set-up time, and
are easy to use and maintain. Although the weapons
have limited range, and their accuracy is affected by
poor visibility and adverse weather, they can be fired
from anywhere on land or from boats where there is
unrestricted visibility to the target.
MANDATORY ALTITUDE- An altitude depicted
on an instrument Approach Procedure Chart
requiring the aircraft to maintain altitude at the
depicted value.
MANPADS(See MAN PORTABLE AIR DEFENSE
SYSTEMS.)
MAP(See MISSED APPROACH POINT.)
MARKER BEACON- An electronic navigation
facility transmitting a 75 MHz vertical fan or
boneshaped radiation pattern. Marker beacons are
identified by their modulation frequency and keying
code, and when received by compatible airborne
equipment, indicate to the pilot, both aurally and
visually, that he/she is passing over the facility.
(See INNER MARKER.)
(See MIDDLE MARKER.)
(See OUTER MARKER.)
(Refer to AIM.)
MARSA(See MILITARY AUTHORITY ASSUMES
RESPONSIBILITY FOR SEPARATION OF
AIRCRAFT.)
MAWP- Missed Approach Waypoint
MAXIMUM AUTHORIZED ALTITUDE- A pub‐
lished altitude representing the maximum usable
altitude or flight level for an airspace structure or
route segment. It is the highest altitude on a Federal
airway, jet route, area navigation low or high route,
or other direct route for which an MEA is designated
in 14 CFR Part 95 at which adequate reception of
navigation aid signals is assured.
MAYDAY- The international radiotelephony distress
signal. When repeated three times, it indicates
Pilot/Controller Glossary 2/14/08
PCG M-2
imminent and grave danger and that immediate
assistance is requested.
(See PAN‐PAN.)
(Refer to AIM.)
MCA(See MINIMUM CROSSING ALTITUDE.)
MDA(See MINIMUM DESCENT ALTITUDE.)
MEA(See MINIMUM EN ROUTE IFR ALTITUDE.)
MEARTS(See MICRO‐EN ROUTE AUTOMATED RADAR
TRACKING SYSTEM.)
METEOROLOGICAL IMPACT STATEMENT-
An unscheduled planning forecast describing
conditions expected to begin within 4 to 12 hours
which may impact the flow of air traffic in a specific
center's (ARTCC) area.
METER FIX ARC- A semicircle, equidistant from
a meter fix, usually in low altitude relatively close to
the meter fix, used to help CTAS/HOST calculate a
meter time, and determine appropriate sector meter
list assignments for aircraft not on an established
arrival route or assigned a meter fix.
METER FIX TIME/SLOT TIME- A calculated time
to depart the meter fix in order to cross the vertex at
the ACLT. This time reflects descent speed
adjustment and any applicable time that must be
absorbed prior to crossing the meter fix.
METER LIST(See ARRIVAL SECTOR ADVISORY LIST.)
METER LIST DISPLAY INTERVAL- A dynamic
parameter which controls the number of minutes
prior to the flight plan calculated time of arrival at the
meter fix for each aircraft, at which time the TCLT is
frozen and becomes an ACLT; i.e., the VTA is
updated and consequently the TCLT modified as
appropriate until frozen at which time updating is
suspended and an ACLT is assigned. When frozen,
the flight entry is inserted into the arrival sector's
meter list for display on the sector PVD/MDM.
MLDI is used if filed true airspeed is less than or
equal to freeze speed parameters (FSPD).
METERING- A method of time‐regulating arrival
traffic flow into a terminal area so as not to exceed a
predetermined terminal acceptance rate.
METERING AIRPORTS- Airports adapted for
metering and for which optimum flight paths are
defined. A maximum of 15 airports may be adapted.
METERING FIX- A fix along an established route
from over which aircraft will be metered prior to
entering terminal airspace. Normally, this fix should
be established at a distance from the airport which
will facilitate a profile descent 10,000 feet above
airport elevation (AAE) or above.
METERING POSITION(S )- Adapted PVDs/
MDMs and associated “D” positions eligible for
display of a metering position list. A maximum of
four PVDs/MDMs may be adapted.
METERING POSITION LIST- An ordered list of
data on arrivals for a selected metering airport
displayed on a metering position PVD/MDM.
MFT(See METER FIX TIME/SLOT TIME.)
MHA(See MINIMUM HOLDING ALTITUDE.)
MIA(See MINIMUM IFR ALTITUDES.)
MICROBURST- A small downburst with outbursts
of damaging winds extending 2.5 miles or less. In
spite of its small horizontal scale, an intense
microburst could induce wind speeds as high as 150
knots
(Refer to AIM.)
MIC RO‐EN ROUTE AUTOMATED RADAR
TRACKING SYSTEM (MEARTS)- An automated
radar and radar beacon tracking system capable of
employing both short‐range (ASR) and long‐range
(ARSR) radars. This microcomputer driven system
provides improved tracking, continuous data record‐
ing, and use of full digital radar displays.
MICROWAVE LANDING SYSTEM- A precision
instrument approach system operating in the
microwave spectrum which normally consists of the
following components:
a. Azimuth Station.
b. Elevation Station.
c. Precision Distance Measuring Equipment.
(See MLS CATEGORIES.)
MID RVR(See VISIBILITY.)
MIDDLE COMPASS LOCATOR(See COMPASS LOCATOR.)
Pilot/Controller Glossary 2/14/08
PCG M-3
MIDDLE MARKER- A marker beacon that defines
a point along the glideslope of an ILS normally
located at or near the point of decision height (ILS
Category I). It is keyed to transmit alternate dots and
dashes, with the alternate dots and dashes keyed at the
rate of 95 dot/dash combinations per minute on a
1300 Hz tone, which is received aurally and visually
by compatible airborne equipment.
(See INSTRUMENT LANDING SYSTEM.)
(See MARKER BEACON.)
(Refer to AIM.)
MILES‐IN‐TRAIL- A specified distance between
aircraft, normally, in the same stratum associated
with the same destination or route of flight.
MILITARY AUTHORITY ASSUMES RESPONSI‐
BILITY FOR SEPARATION OF AIRCRAFT- A
condition whereby the military services involved
assume responsibility for separation between
participating military aircraft in the ATC system. It is
used only for required IFR operations which are
specified in letters of agreement or other appropriate
FAA or military documents.
MILITARY LANDING ZONE- A landing strip used
exclusively by the military for training. A military
landing zone does not carry a runway designation.
MILITARY OPERATIONS AREA(See SPECIAL USE AIRSPACE.)
MILITARY TRAINING ROUTES- Airspace of
defined vertical and lateral dimensions established
for the conduct of military flight training at airspeeds
in excess of 250 knots IAS.
(See IFR MILITARY TRAINING ROUTES.)
(See VFR MILITARY TRAINING ROUTES.)
MINIMA(See MINIMUMS.)
MINIMUM CROSSING ALTITUDE- The lowest
altitude at certain fixes at which an aircraft must cross
when proceeding in the direction of a higher
minimum en route IFR altitude (MEA).
(See MINIMUM EN ROUTE IFR ALTITUDE.)
MINIMUM DESCENT ALTITUDE- The lowest
altitude, expressed in feet above mean sea level, to
which descent is authorized on final approach or
during circle‐to‐land maneuvering in execution of a
standard instrument approach procedure where no
electronic glideslope is provided.
(See NONPRECISION APPROACH
PROCEDURE.)
MINIMUM EN ROUTE IFR ALTITUDE (MEA)-
The lowest published altitude between radio fixes
which assures acceptable navigational signal cover‐
age and meets obstacle clearance requirements
between those fixes. The MEA prescribed for a
Federal airway or segment thereof, area navigation
low or high route, or other direct route applies to the
entire width of the airway, segment, or route between
the radio fixes defining the airway, segment, or route.
(Refer to 14 CFR Part 91.)
(Refer to 14 CFR Part 95.)
(Refer to AIM.)
MINIMUM FRICTION LEVEL- The friction level
specified in AC 150/5320‐12, Measurem ent,
Construction, and Maintenance of Skid Resistant
Airport Pavement Surfaces, that represents the
minimum recommended wet pavement surface
friction value for any turbojet aircraft engaged in
LAHSO. This value will vary with the particular
friction measurement equipment used.
MINIMUM FUEL- Indicates that an aircraft's fuel
supply has reached a state where, upon reaching the
destination, it can accept little or no delay. This is not
an emergency situation but merely indicates an
emergency situation is possible should any undue
delay occur.
(Refer to AIM.)
MINIMUM HOLDING ALTITUDE- The lowest
altitude prescribed for a holding pattern which
assures navigational signal coverage, communica‐
tions, and meets obstacle clearance requirements.
MINIMUM IFR ALTITUDES (MIA)- Minimum
altitudes for IFR operations as prescribed in 14 CFR
Part 91. These altitudes are published on aeronautical
charts and prescribed in 14 CFR Part 95 for airways
and routes, and in 14 CFR Part 97 for standard
instrument approach procedures. If no applicable
minimum altitude is prescribed in 14 CFR Part 95 or
14 CFR Part 97, the following minimum IFR
altitude applies:
a. In designated mountainous areas, 2,000 feet
above the highest obstacle within a horizontal
distance of 4 nautical miles from the course to be
flown; or
Pilot/Controller Glossary 2/14/08
PCG M-4
b. Other than mountainous areas, 1,000 feet above
the highest obstacle within a horizontal distance of 4
nautical miles from the course to be flown; or
c. As otherwise authorized by the Administrator
or assigned by ATC.
(See MINIMUM CROSSING ALTITUDE.)
(See MINIMUM EN ROUTE IFR ALTITUDE.)
(See MINIMUM OBSTRUCTION CLEARANCE
ALTITUDE.)
(See MINIMUM SAFE ALTITUDE.)
(See MINIMUM VECTORING ALTITUDE.)
(Refer to 14 CFR Part 91.)
MINIMUM NAVIGATION PERFORMANCE
SPECIFICATION- A set of standards which require
aircraft to have a minimum navigation performance
capability in order to operate in MNPS designated
airspace. In addition, aircraft must be certified by
their State of Registry for MNPS operation.
MINIMUM NAVIGATION PERFORMANCE
SPECIFICATION AIRSPACE- Designated airspace
in which MNPS procedures are applied between
MNPS certified and equipped aircraft. Under certain
conditions, non‐MNPS aircraft can operate in
MNPSA. However, standard oceanic separation
minima is provided between the non‐MNPS aircraft
and other traffic. Currently, the only designated
MNPSA is described as follows:
a. Between FL 285 and FL 420;
b. Between latitudes 27N and the North Pole;
c. In the east, the eastern boundaries of the CTAs
Santa Maria Oceanic, Shanwick Oceanic, and
Reykjavik;
d. In the west, the western boundaries of CTAs
Reykjavik and Gander Oceanic and New York
Oceanic excluding the area west of 60W and south
of 3830'N.
MINIMUM OBSTRUCTION CLEARANCE ALTI‐
TUDE (MOCA)- The lowest published altitude in
effect between radio fixes on VOR airways,
off‐airway routes, or route segments which meets
obstacle clearance requirements for the entire route
segment and which assures acceptable navigational
signal coverage only within 25 statute (22 nautical)
miles of a VOR.
(Refer to 14 CFR Part 91.)
(Refer to 14 CFR Part 95.)
MINIMUM RECEPTION ALTITUDE- The lowest
altitude at which an intersection can be determined.
(Refer to 14 CFR Part 95.)
MINIMUM SAFE ALTITUDEa. The minimum altitude specified in 14 CFR
Part 91 for various aircraft operations.
b. Altitudes depicted on approach charts which
provide at least 1,000 feet of obstacle clearance for
emergency use within a specified distance from the
navigation facility upon which a procedure is
predicated. These altitudes will be identified as
Minimum Sector Altitudes or Emergency Safe
Altitudes and are established as follows:
1. Minimum Sector Altitudes. Altitudes de‐
picted on approach charts which provide at least
1,000 feet of obstacle clearance within a 25‐mile
radius of the navigation facility upon which the
procedure is predicated. Sectors depicted on
approach charts must be at least 90 degrees in scope.
These altitudes are for emergency use only and do not
necessarily assure acceptable navigational signal
coverage.
(See ICAO term Minimum Sector Altitude.)
2. Emergency Safe Altitudes. Altitudes de‐
picted on approach charts which provide at least
1,000 feet of obstacle clearance in nonmountainous
areas and 2,000 feet of obstacle clearance in
designated mountainous areas within a 100‐mile
radius of the navigation facility upon which the
procedure is predicated and normally used only in
military procedures. These altitudes are identified on
published procedures as “Emergency Safe Alti‐
tudes.”
MINIMUM SAFE ALTITUDE WARNING- A
function of the ARTS III computer that aids the
controller by alerting him/her when a tracked Mode
C equipped aircraft is below or is predicted by the
computer to go below a predetermined minimum safe
altitude.
(Refer to AIM.)
MINIMUM SECTOR ALTITUDE - The
lowest altitude which may be used under emergency
conditions which will provide a minimum clearance
of 300 m (1,000 feet) above all obstacles located in
an area contained within a sector of a circle of 46 km
(25 NM) radius centered on a radio aid to navigation.
MINIMUMS- Weather condition requirements
established for a particular operation or type of
Pilot/Controller Glossary 2/14/08
PCG M-5
operation; e.g., IFR takeoff or landing, alternate
airport for IFR flight plans, VFR flight, etc.
(See IFR CONDITIONS.)
(See IFR TAKEOFF MINIMUMS AND
DEPARTURE PROCEDURES.)
(See LANDING MINIMUMS.)
(See VFR CONDITIONS.)
(Refer to 14 CFR Part 91.)
(Refer to AIM.)
MINIMUM VECTORING ALTITUDE (MVA)-
The lowest MSL altitude at which an IFR aircraft will
be vectored by a radar controller, except as otherwise
authorized for radar approaches, departures, and
missed approaches. The altitude meets IFR obstacle
clearance criteria. It may be lower than the published
MEA along an airway or J‐route segment. It may be
utilized for radar vectoring only upon the controller's
determination that an adequate radar return is being
received from the aircraft being controlled. Charts
depicting minimum vectoring altitudes are normally
available only to the controllers and not to pilots.
(Refer to AIM.)
MINUTES‐IN‐TRAIL- A specified interval be‐
tween aircraft expressed in time. This method would
more likely be utilized regardless of altitude.
MIS(See METEOROLOGICAL IMPACT
STATEMENT.)
MISSED APPROACH-
a. A maneuver conducted by a pilot when an
instrument approach cannot be completed to a
landing. The route of flight and altitude are shown on
instrument approach procedure charts. A pilot
executing a missed approach prior to the Missed
Approach Point (MAP) must continue along the final
approach to the MAP.
b. A term used by the pilot to inform ATC that
he/she is executing the missed approach.
c. At locations where ATC radar service is
provided, the pilot should conform to radar vectors
when provided by ATC in lieu of the published
missed approach procedure.
(See MISSED APPROACH POINT.)
(Refer to AIM.)
MISSED APPROACH POINT- A point prescribed
in each instrument approach procedure at which a
missed approach procedure shall be executed if the
required visual reference does not exist.
(See MISSED APPROACH.)
(See SEGMENTS OF AN INSTRUMENT
APPROACH PROCEDURE.)
MISSED APPROACH PROCEDURE - The
procedure to be followed if the approach cannot be
continued.
MISSED APPROACH SEGMENT(See SEGMENTS OF AN INSTRUMENT
APPROACH PROCEDURE.)
MLDI(See METER LIST DISPLAY INTERVAL.)
MLS(See MICROWAVE LANDING SYSTEM.)
MLS CATEGORIESa. MLS Category I. An MLS approach procedure
which provides for an approach to a height above
touchdown of not less than 200 feet and a runway
visual range of not less than 1,800 feet.
b. MLS Category II. Undefined until data gather‐
ing/analysis completion.
c. MLS Category III. Undefined until data
gathering/analysis completion.
MM(See MIDDLE MARKER.)
MNPS(See MINIMUM NAVIGATION PERFORMANCE
SPECIFICATION.)
MNPSA(See MINIMUM NAVIGATION PERFORMANCE-
SPECIFICATION AIRSPACE.)
MOA(See MILITARY OPERATIONS AREA.)
MOCA(See MINIMUM OBSTRUCTION CLEARANCE
ALTITUDE.)
MODE- The letter or number assigned to a specific
pulse spacing of radio signals transmitted or received
by ground interrogator or airborne transponder
components of the Air Traffic Control Radar Beacon
Pilot/Controller Glossary 2/14/08
PCG M-6
System (ATCRBS). Mode A (military Mode 3) and
Mode C (altitude reporting) are used in air traffic
control.
(See INTERROGATOR.)
(See RADAR.)
(See TRANSPONDER.)
(See ICAO term MODE.)
(Refer to AIM.)
MODE (SSR MODE) - The letter or number
assigned to a specific pulse spacing of the
interrogation signals transmitted by an interrogator.
There are 4 modes, A, B, C and D specified in Annex
10, corresponding to four different interrogation
pulse spacings.
MODE C INTRUDER ALERT- A function of
certain air traffic control automated systems designed
to alert radar controllers to existing or pending
situations between a tracked target (known IFR or
VFR aircraft) and an untracked target (unknown IFR
or VFR aircraft) that requires immediate attention/
action.
(See CONFLICT ALERT.)
MONITOR- (When used with communication
transfer) listen on a specific frequency and stand by
for instructions. Under normal circumstances do not
establish communications.
MONITOR ALERT (MA)- A function of the ETMS
that provides traffic management personnel with a
tool for predicting potential capacity problems in
individual operational sectors. The MA is an
indication that traffic management personnel need to
analyze a particular sector for actual activity and to
determine the required action(s), if any, needed to
control the demand.
MONITOR ALERT PARAMETER (MAP)- The
number designated for use in monitor alert
processing by the ETMS. The MAP is designated for
each operational sector for increments of 15 minutes.
MOSAIC/MULTI-SENSOR MODE- Accepts posi‐
tional data from multiple radar or ADS-B sites.
Targets are displayed from a single source within a
radar sort box according to the hierarchy of the
sources assigned.
MOVEMENT AREA- The runways, taxiways, and
other areas of an airport/heliport which are utilized
for taxiing/hover taxiing, air taxiing, takeoff, and
landing of aircraft, exclusive of loading ramps and
parking areas. At those airports/heliports with a
tower, specific approval for entry onto the movement
area must be obtained from ATC.
(See ICAO term MOVEMENT AREA.)
MOVEMENT AREA - That part of an
aerodrome to be used for the takeoff, landing and
taxiing of aircraft, consisting of the maneuvering area
and the apron(s).
MOVING TARGET INDICATOR- An electronic
device which will permit radar scope presentation
only from targets which are in motion. A partial
remedy for ground clutter.
MRA(See MINIMUM RECEPTION ALTITUDE.)
MSA(See MINIMUM SAFE ALTITUDE.)
MSAW(See MINIMUM SAFE ALTITUDE WARNING.)
MTI(See MOVING TARGET INDICATOR.)
MTR(See MILITARY TRAINING ROUTES.)
MULTICOM- A mobile service not open to public
correspondence used to provide communications
essential to conduct the activities being performed by
or directed from private aircraft.
MULTIPLE RUNWAYS- The utilization of a
dedicated arrival runway(s) for departures and a
dedicated departure runway(s) for arrivals when
feasible to reduce delays and enhance capacity.
MVA(See MINIMUM VECTORING ALTITUDE.)
Pilot/Controller Glossary 2/14/08
PCG N-1
N
NAS(See NATIONAL AIRSPACE SYSTEM.)
NATIONAL AIRSPACE SYSTEM- The common
network of U.S. airspace; air navigation facilities,
equipment and services, airports or landing areas;
aeronautical charts, information and services; rules,
regulations and procedures, technical information,
and manpower and material. Included are system
components shared jointly with the military.
NATIONAL BEACON CODE ALLOCATION
PLAN AIRSPACE- Airspace over United States
territory located within the North American continent
between Canada and Mexico, including adjacent
territorial waters outward to about boundaries of
oceanic control areas (CTA)/Flight Information
Regions (FIR).
(See FLIGHT INFORMATION REGION.)
NATIONAL FLIGHT DATA CENTER- A facility in
Washington D.C., established by FAA to operate a
central aeronautical information service for the
collection, validation, and dissemination of aeronau‐
tical data in support of the activities of government,
industry, and the aviation community. The informa‐
tion is published in the National Flight Data Digest.
(See NATIONAL FLIGHT DATA DIGEST.)
NATIONAL FLIGHT DATA DIGEST- A daily
(except weekends and Federal holidays) publication
of flight information appropriate to aeronautical
charts, aeronautical publications, Notices to Airmen,
or other media serving the purpose of providing
operational flight data essential to safe and efficient
aircraft operations.
NATIONAL SEARCH AND RESCUE PLAN- An
interagency agreement which provides for the
effective utilization of all available facilities in all
types of search and rescue missions.
NAVAID(See NAVIGATIONAL AID.)
NAVAID CLASSES- VOR, VORTAC, and TACAN
aids are classed according to their operational use.
The three classes of NAVAIDs are:
a. T- Terminal.
b. L- Low altitude.
c. H- High altitude.
Note:The normal service range for T, L, and H class
aids is found in the AIM. Certain operational
requirements make it necessary to use some of
these aids at greater service ranges than
specified. Extended range is made possible
through flight inspection determinations. Some
aids also have lesser service range due to location,
terrain, frequency protection, etc. Restrictions to
service range are listed in Airport/Facility
Directory.
NAVIGABLE AIRSPACE- Airspace at and above
the minimum flight altitudes prescribed in the CFRs
including airspace needed for safe takeoff and
landing.
(Refer to 14 CFR Part 91.)
NAVIGATION REFERENCE SYSTEM (NRS)-
The NRS is a system of waypoints developed for use
within the United States for flight planning and
navigation without reference to ground based
navigational aids. The NRS waypoints are located in
a grid pattern along defined latitude and longitude
lines. The initial use of the NRS will be in the high
altitude environment in conjunction with the High
Altitude Redesign initiative. The NRS waypoints are
intended for use by aircraft capable of point-to-point
navigation.
NAVIGATIONAL AID- Any visual or electronic
device airborne or on the surface which provides
point‐to‐point guidance information or position data
to aircraft in flight.
(See AIR NAVIGATION FACILITY.)
NBCAP AIRSPACE(See NATIONAL BEACON CODE ALLOCATION
PLAN AIRSPACE.)
NDB(See NONDIRECTIONAL BEACON.)
NEGATIVE- “No,” or “permission not granted,” or
“that is not correct.”
NEGATIVE CONTACT- Used by pilots to inform
ATC that:
a. Previously issued traffic is not in sight. It may
be followed by the pilot's request for the controller to
provide assistance in avoiding the traffic.
b. They were unable to contact ATC on a
particular frequency.
Pilot/Controller Glossary 2/14/08
PCG N-2
NFDC(See NATIONAL FLIGHT DATA CENTER.)
NFDD(See NATIONAL FLIGHT DATA DIGEST.)
NIGHT- The time between the end of evening civil
twilight and the beginning of morning civil twilight,
as published in the American Air Almanac, converted
to local time.
(See ICAO term NIGHT.)
NIGHT - The hours between the end of
evening civil twilight and the beginning of morning
civil twilight or such other period between sunset and
sunrise as may be specified by the appropriate
authority.
Note:Civil twilight ends in the evening when the
center of the sun's disk is 6 degrees below the
horizon and begins in the morning when the center
of the sun's disk is 6 degrees below the horizon.
NO GYRO APPROACH- A radar approach/vector
provided in case of a malfunctioning gyro‐compass
or directional gyro. Instead of providing the pilot
with headings to be flown, the controller observes the
radar track and issues control instructions “turn
right/left” or “stop turn” as appropriate.
(Refer to AIM.)
NO GYRO VECTOR(See NO GYRO APPROACH.)
NO TRANSGRESSION ZONE (NTZ)- The NTZ is
a 2,000 foot wide zone, located equidistant between
parallel runway final approach courses in which
flight is not allowed.
NONAPPROACH CONTROL TOWER- Author‐
izes aircraft to land or takeoff at the airport controlled
by the tower or to transit the Class D airspace. The
primary function of a nonapproach control tower is
the sequencing of aircraft in the traffic pattern and on
the landing area. Nonapproach control towers also
separate aircraft operating under instrument flight
rules clearances from approach controls and centers.
They provide ground control services to aircraft,
vehicles, personnel, and equipment on the airport
movement area.
NONCOMMON ROUTE/PORTION- That segment
of a North American Route between the inland
navigation facility and a designated North American
terminal.
NONCOMPOSITE SEPARATION- Separation in
accordance with minima other than the composite
separation minimum specified for the area con‐
cerned.
NONDIRECTIONAL BEACON- An L/MF or UHF
radio beacon transmitting nondirectional signals
whereby the pilot of an aircraft equipped with
direction finding equipment can determine his/her
bearing to or from the radio beacon and “home” on or
track to or from the station. When the radio beacon is
installed in conjunction with the Instrument Landing
System marker, it is normally called a Compass
Locator.
(See AUTOMATIC DIRECTION FINDER.)
(See COMPASS LOCATOR.)
