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 [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 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 [ICAO]-The flight plan, including changes, if any, brought about by subsequent clearances.