Pilot/Controller Glossary 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. CLIMB VIA" An abbreviated ATC clearance that requires compliance with the procedure lateral path, associated speed restrictions, and altitude restrictions along the cleared route or procedure. CLOSE PARALLEL RUNWAYS- Two parallel runways whose extended centerlines are separated by less than 4,300 feet and at least 3000 feet (750 feet for SOIA operations) for which ATC is authorized to conduct simultaneous independent approach operations. PRM and simultaneous close parallel appear in approach title. Dual communications, special pilot training, an Attention All Users Page (AAUP), NTZ monitoring by displays that have aural and visual alerting algorithms are required. A high update rate surveillance sensor is required for certain runway or approach course spacing. CLOSED LOOP CLEARANCE- A vector or reroute clearance that includes a return to route point and updates ERAM to accurately reflect the anticipated route (e.g., a QU route pick that anticipates length of vector and includes the next fix that ties into the route of flight.) 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.) COA- (See CERTIFICATE OF WAIVER OR AUTHORIZATION.) 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.) COLD TEMPERATURE CORRECTION- A correction in feet, based on height above airport and temperature, that is added to the aircraft"s indicated altitude to offset the effect of cold temperature on true altitude. COLLABORATIVE TRAJECTORY OPTIONS PROGRAM (CTOP)- CTOP is a traffic management program administered by the Air Traffic Control System Command Center (ATCSCC) that manages demand through