Pilot/Controller Glossary

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.
(See DESIGNATED COMMON TRAFFIC
ADVISORY FREQUENCY (CTAF) AREA.)
(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.)

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."
COMPUTER NAVIGATION FIX (CNF)- A
Computer Navigation Fix is a point defined by a
latitude/longitude coordinate and is required to
support Performance-Based Navigation (PBN)
operations. A five-letter identifier denoting a CNF
can be found next to an "x" on en route charts and on
some approach charts. Eventually, all CNFs will be
labeled and begin with the letters "CF" followed by
three consonants (e.g., "CFWBG"). CNFs are not
recognized by ATC, are not contained in ATC fix or
automation databases, and are not used for ATC
purposes. Pilots should not use CNFs for point-to-
point navigation (e.g., proceed direct), filing a flight
plan, or in aircraft/ATC communications. Use of
CNFs has not been adopted or recognized by the
International Civil Aviation Organization (ICAO).
(REFER to AIM 1-1-17b5(i)(2), Global
Positioning System (GPS).