Pilot/Controller Glossary CALCULATED LANDING TIME- A term that may be used in place of tentative or actual calculated landing time, whichever applies. CALIBRATED AIRSPEED (CAS) " The indicated airspeed of an aircraft, corrected for position and instrument error. Calibrated airspeed is equal to true airspeed in standard atmosphere at sea level. 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. CBO- (See COMMUNITY-BASED ORGANIZATION.) 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. 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 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 AIRMET.) (See CONVECTIVE SIGMET.) (See GRAPHICAL AIRMEN"S METEOROLOGICAL INFORMATION.) (See SAW.) (See SIGMET.) (Refer to AIM.)