C
CALCULATED LANDING TIME- A
term that may be used in place of tentative or actual calculated landing time,
whichever applies.
CALL FOR RELEASE- Wherein
the overlying ARTCC requires a terminal facility to initiate verbal coordination
to secure ARTCC approval for release of a departure into the en route
environment.
CALL UP- Initial voice
contact between a facility and an aircraft, using the identification of the unit
being called and the unit initiating the call.
(Refer to AIM.)
CANADIAN MINIMUM
NAVIGATION PERFORMANCE SPECIFICATION AIRSPACE- That portion of Canadian domestic
airspace within which MNPS separation may be applied.
CARDINAL ALTITUDES- “Odd”
or “Even” thousand‐foot altitudes or flight levels; e.g., 5,000, 6,000, 7,000,
FL 250, FL 260, FL 270.
(See ALTITUDE.)
(See FLIGHT LEVEL.)
CARDINAL FLIGHT LEVELS-
(See CARDINAL ALTITUDES.)
CAT-
(See CLEAR‐AIR TURBULENCE.)
CATCH POINT- A
fix/waypoint that serves as a transition point from the high altitude waypoint
navigation structure to an arrival procedure (STAR) or the low altitude
ground-based navigation structure.
CEILING- The heights above
the earth's surface of the lowest layer of clouds or obscuring phenomena that is
reported as “broken,” “overcast,” or “obscuration,” and not classified as “thin”
or “partial.”
(See ICAO term CEILING.)
CEILING [ICAO]- The height
above the ground or water of the base of the lowest layer of cloud below 6,000
meters (20,000 feet) covering more than half the sky.
CENRAP-
(See CENTER RADAR ARTS
PRESENTATION/PROCESSING.)
CENRAP‐PLUS-
(See CENTER RADAR ARTS
PRESENTATION/PROCESSING‐PLUS.)
CENTER-
(See AIR ROUTE TRAFFIC
CONTROL CENTER.)
CENTER'S AREA- The
specified airspace within which an air route traffic control center (ARTCC)
provides air traffic control and advisory service.
(See AIR ROUTE TRAFFIC
CONTROL CENTER.)
(Refer to AIM.)
CENTER RADAR ARTS
PRESENTATION/PROCESSING- A computer program developed to provide a back‐up
system for airport surveillance radar in the event of a failure or malfunction.
The program uses air route traffic control center radar for the processing and
presentation of data on the ARTS IIA or IIIA displays.
CENTER RADAR ARTS
PRESENTATION/PROCESSING‐PLUS- A computer program developed to provide a back‐up
system for airport surveillance radar in the event of a terminal secondary radar
system failure. The program uses a combination of Air Route Traffic Control
Center Radar and terminal airport surveillance radar primary targets displayed
simultaneously for the processing and presentation of data on the ARTS IIA or
IIIA displays.
CENTER TRACON AUTOMATION
SYSTEM (CTAS)- A computerized set of programs designed to aid Air Route Traffic
Control Centers and TRACONs in the management and control of air traffic.
CENTER WEATHER ADVISORY-
An unscheduled weather advisory issued by Center Weather Service Unit
meteorologists for ATC use to alert pilots of existing or anticipated adverse
weather conditions within the next 2 hours. A CWA may modify or redefine a
SIGMET.
(See AWW.)
(See AIRMET.)
(See CONVECTIVE SIGMET.)
(See SIGMET.)
(Refer to AIM.)
CENTRAL
EAST PACIFIC- An organized route system between the U.S. West Coast and Hawaii.
CEP-
(See CENTRAL EAST PACIFIC.)
CERAP-
(See COMBINED CENTER‐RAPCON.)
CERTIFIED TOWER RADAR
DISPLAY (CTRD)- A FAA radar display certified for use in the NAS.
CFR-
(See CALL FOR RELEASE.)
CHAFF- Thin, narrow
metallic reflectors of various lengths and frequency responses, used to reflect
radar energy. These reflectors when dropped from aircraft and allowed to drift
downward result in large targets on the radar display.
CHARTED VFR FLYWAYS-
Charted VFR Flyways are flight paths recommended for use to bypass areas heavily
traversed by large turbine‐powered aircraft. Pilot compliance with recommended
flyways and associated altitudes is strictly voluntary. VFR Flyway Planning
charts are published on the back of existing VFR Terminal Area charts.
CHARTED VISUAL FLIGHT
PROCEDURE APPROACH- An approach conducted while operating on an instrument
flight rules (IFR) flight plan which authorizes the pilot of an aircraft to
proceed visually and clear of clouds to the airport via visual landmarks and
other information depicted on a charted visual flight procedure. This approach
must be authorized and under the control of the appropriate air traffic control
facility. Weather minimums required are depicted on the chart.
CHASE- An
aircraft flown in proximity to another aircraft normally to observe its
performance during training or testing.
CHASE AIRCRAFT-
(See CHASE.)
CIRCLE‐TO‐LAND MANEUVER- A
maneuver initiated by the pilot to align the aircraft with a runway for landing
when a straight‐in landing from an instrument approach is not possible or is not
desirable. At tower controlled airports, this maneuver is made only after ATC
authorization has been obtained and the pilot has established required visual
reference to the airport.
(See CIRCLE TO RUNWAY.)
(See LANDING MINIMUMS.)
(Refer to AIM.)
CIRCLE TO RUNWAY
(RUNWAY NUMBER)- Used by ATC to inform the pilot that he/she must circle
to land because the runway in use is other than the runway aligned with the
instrument approach procedure. When the direction of the circling maneuver in
relation to the airport/runway is required, the controller will state the
direction (eight cardinal compass points) and specify a left or right downwind
or base leg as appropriate; e.g., “Cleared VOR Runway Three Six Approach circle
to Runway Two Two,” or “Circle northwest of the airport for a right downwind to
Runway Two Two.”
(See CIRCLE‐TO‐LAND
MANEUVER.)
(See LANDING MINIMUMS.)
(Refer to AIM.)
CIRCLING APPROACH-
(See CIRCLE‐TO‐LAND
MANEUVER.)
CIRCLING MANEUVER-
(See CIRCLE‐TO‐LAND
MANEUVER.)
CIRCLING MINIMA-
(See LANDING MINIMUMS.)
CLASS A AIRSPACE-
(See CONTROLLED AIRSPACE.)
CLASS B AIRSPACE-
(See CONTROLLED AIRSPACE.)
CLASS C AIRSPACE-
(See CONTROLLED AIRSPACE.)
CLASS D AIRSPACE-
(See CONTROLLED AIRSPACE.)
CLASS E AIRSPACE-
(See CONTROLLED AIRSPACE.)
CLASS G AIRSPACE- That
airspace not designated as Class A, B, C, D or E.
CLEAR AIR TURBULENCE
(CAT)- Turbulence encountered in air where no clouds are present. This term is
commonly applied to high‐level turbulence associated with wind shear. CAT is
often encountered in the vicinity of the jet stream.
(See WIND SHEAR.)
(See JET STREAM.)
CLEAR OF THE RUNWAY-
a. Taxiing
aircraft, which is approaching a runway, is clear of the runway when all parts
of the aircraft are held short of the applicable runway holding position
marking.
b. A
pilot or controller may consider an aircraft, which is exiting or crossing a
runway, to be clear of the runway when all parts of the aircraft are beyond the
runway edge and there are no restrictions to its continued movement beyond the
applicable runway holding position marking.
c. Pilots and
controllers shall exercise good judgement to ensure that adequate separation
exists between all aircraft on runways and taxiways at airports with inadequate
runway edge lines or holding position markings.
CLEARANCE-
(See AIR TRAFFIC CLEARANCE.)
CLEARANCE LIMIT- The fix,
point, or location to which an aircraft is cleared when issued an air traffic
clearance.
(See ICAO term CLEARANCE
LIMIT.)
CLEARANCE LIMIT [ICAO]-
The point to which an aircraft is granted an air traffic control clearance.
CLEARANCE VOID IF
NOT OFF BY (TIME)- Used by ATC to advise an aircraft that the departure
clearance is automatically canceled if takeoff is not made prior to a specified
time. The pilot must obtain a new clearance or cancel his/her IFR flight plan if
not off by the specified time.
(See ICAO term CLEARANCE VOID
TIME.)
CLEARANCE VOID TIME [ICAO]-
A time specified by an air traffic control unit at which a clearance ceases to
be valid unless the aircraft concerned has already taken action to comply
therewith.
CLEARED APPROACH-
ATC authorization for an aircraft to execute any standard or special
instrument approach procedure for that airport. Normally, an aircraft will be
cleared for a specific instrument approach procedure.
(See CLEARED (Type of)
APPROACH.)
(See INSTRUMENT APPROACH
PROCEDURE.)
(Refer to 14 CFR Part 91.)
(Refer to AIM.)
CLEARED (Type of)
APPROACH- ATC authorization for an aircraft to execute a specific
instrument approach procedure to an airport; e.g., “Cleared ILS Runway Three Six
Approach.”
(See APPROACH CLEARANCE.)
(See INSTRUMENT APPROACH
PROCEDURE.)
(Refer to 14 CFR Part 91.)
(Refer to AIM.)
CLEARED AS FILED-
Means the aircraft is cleared to proceed in accordance with the route of
flight filed in the flight plan. This clearance does not include the altitude,
DP, or DP Transition.
(See REQUEST FULL ROUTE
CLEARANCE.)
(Refer to AIM.)
CLEARED FOR TAKEOFF-
ATC authorization for an aircraft to depart. It is predicated on known
traffic and known physical airport conditions.
CLEARED FOR THE
OPTION- ATC authorization for an aircraft to make a touch‐and‐go, low
approach, missed approach, stop and go, or full stop landing at the discretion
of the pilot. It is normally used in training so that an instructor can evaluate
a student's performance under changing situations.
(See OPTION APPROACH.)
(Refer to AIM.)
CLEARED THROUGH-
ATC authorization for an aircraft to make intermediate stops at specified
airports without refiling a flight plan while en route to the clearance limit.
CLEARED TO LAND-
ATC authorization for an aircraft to land. It is predicated on known traffic
and known physical airport conditions.
CLEARWAY- An area beyond
the takeoff runway under the control of airport authorities within which terrain
or fixed obstacles may not extend above specified limits. These areas may be
required for certain turbine‐powered operations and the size and upward slope of
the clearway will differ depending on when the aircraft was certificated.
(Refer to 14 CFR Part 1.)
CLIMB TO VFR-
ATC authorization for an aircraft to climb to VFR conditions within Class B,
C, D, and E surface areas when the only weather limitation is restricted
visibility. The aircraft must remain clear of clouds while climbing to VFR.
(See SPECIAL VFR CONDITIONS.)
(Refer to AIM.)
CLIMBOUT- That portion of
flight operation between takeoff and the initial cruising altitude.
CLOSE
PARALLEL RUNWAYS- Two parallel runways whose extended centerlines are separated
by less than 4,300 feet, having a Precision Runway Monitoring (PRM) system that
permits simultaneous independent ILS approaches.
CLOSED RUNWAY- A runway
that is unusable for aircraft operations. Only the airport management/military
operations office can close a runway.
CLOSED TRAFFIC- Successive
operations involving takeoffs and landings or low approaches where the aircraft
does not exit the traffic pattern.
CLOUD- A cloud is a
visible accumulation of minute water droplets and/or ice particles in the
atmosphere above the Earth's surface. Cloud differs from ground fog, fog, or ice
fog only in that the latter are, by definition, in contact with the Earth's
surface.
CLT-
(See CALCULATED LANDING
TIME.)
CLUTTER- In radar
operations, clutter refers to the reception and visual display of radar returns
caused by precipitation, chaff, terrain, numerous aircraft targets, or other
phenomena. Such returns may limit or preclude ATC from providing services based
on radar.
(See CHAFF.)
(See GROUND CLUTTER.)
(See PRECIPITATION.)
(See TARGET.)
(See ICAO term RADAR
CLUTTER.)
CMNPS-
(See CANADIAN MINIMUM
NAVIGATION PERFORMANCE SPECIFICATION AIRSPACE.)
COASTAL FIX- A navigation
aid or intersection where an aircraft transitions between the domestic route
structure and the oceanic route structure.
CODES- The number assigned
to a particular multiple pulse reply signal transmitted by a transponder.
(See DISCRETE CODE.)
COMBINED CENTER‐RAPCON- An
air traffic facility which combines the functions of an ARTCC and a radar
approach control facility.
(See AIR ROUTE TRAFFIC
CONTROL CENTER.)
(See RADAR APPROACH CONTROL
FACILITY.)
COMMON POINT- A
significant point over which two or more aircraft will report passing or have
reported passing before proceeding on the same or diverging tracks. To
establish/maintain longitudinal separation, a controller may determine a common
point not originally in the aircraft's flight plan and then clear the aircraft
to fly over the point.
(See SIGNIFICANT POINT.)
COMMON PORTION-
(See COMMON ROUTE.)
COMMON ROUTE- That segment
of a North American Route between the inland navigation facility and the coastal
fix.
OR
COMMON ROUTE- Typically
the portion of a RNAV STAR between the en route transition end point and the
runway transition start point; however, the common route may only consist of a
single point that joins the en route and runway transitions.
COMMON TRAFFIC ADVISORY
FREQUENCY (CTAF)- A frequency designed for the purpose of carrying out airport
advisory practices while operating to or from an airport without an operating
control tower. The CTAF may be a UNICOM, Multicom, FSS, or tower frequency and
is identified in appropriate aeronautical publications.
(Refer to AC 90‐42, Traffic
Advisory Practices at Airports Without Operating Control Towers.)
COMPASS LOCATOR- A low
power, low or medium frequency (L/MF) radio beacon installed at the site of the
outer or middle marker of an instrument landing system (ILS). It can be used for
navigation at distances of approximately 15 miles or as authorized in the
approach procedure.
a. Outer Compass
Locator (LOM)- A compass locator installed at the site of the outer marker of an
instrument landing system.
(See OUTER MARKER.)
b. Middle Compass
Locator (LMM)- A compass locator installed at the site of the middle marker of
an instrument landing system.
(See MIDDLE MARKER.)
(See ICAO term LOCATOR.)
COMPASS ROSE- A circle,
graduated in degrees, printed on some charts or marked on the ground at an
airport. It is used as a reference to either true or magnetic direction.
COMPLY WITH RESTRICTIONS-
An ATC instruction that requires an aircraft being vectored back onto an arrival
or departure procedure to comply with all altitude and/or speed restrictions
depicted on the procedure. This term may be used in lieu of repeating each
remaining restriction that appears on the procedure.
COMPOSITE FLIGHT PLAN- A flight plan which specifies VFR operation for one
portion of flight and IFR for another portion. It is used primarily in military
operations.
(Refer to AIM.)
COMPOSITE ROUTE SYSTEM- An
organized oceanic route structure, incorporating reduced lateral spacing between
routes, in which composite separation is authorized.
COMPOSITE SEPARATION- A
method of separating 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 compulsory reporting points when informed by ATC that their
aircraft is in “radar contact.”
CONFIDENCE MANEUVER- A
confidence maneuver consists of one or more turns, a climb or descent, or other
maneuver to determine if the pilot in command (PIC) is able to receive and
comply with ATC instructions.
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 navigations.
CONTACT-
a. 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
contaminated 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.
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 [ICAO]- 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 frequencies assigned to the sector.
(See DISCRETE FREQUENCY.)
CONTROL SLASH- A radar
beacon slash representing 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 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.
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 requirements 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 enplanements. 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 communications 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 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 [ICAO]-
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 [ICAO]- A
person authorized to provide air traffic control services.
CONTROLLER PILOT DATA LINK
COMMUNICATIONS (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
METEOROLOGICAL 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 approaches 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.)
COURSE-
a. 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.
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 [ICAO]-
(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.)
CROSSWIND-
a. 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 component 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 without a standard/special instrument approach procedure. Such a clearance
is NOT AUTHORIZATION 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 [ICAO]- A
level maintained during a significant portion of a flight.
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 traffic management system computer 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 [ICAO]-
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.)
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