CATClear Air Turbulence. Turbulence that occurs in clear skies without visual clues such as clouds, often found near the jet stream at high altitudes.CDICourse Deviation Indicator. A needle on a VOR or GPS display that shows whether the aircraft is left or right of the desired course centerline.CeilingThe height above ground level of the lowest layer of clouds that covers more than half the sky (broken or overcast). Ceilings are reported in METARs and affect VFR flight.Center of GravityThe point at which the aircraft's total weight is considered to be concentrated. It must remain within approved limits for safe and controllable flight.CessnaAn American aircraft manufacturer known for producing popular general aviation aircraft, including the Cessna 172 Skyhawk, the most produced aircraft in history.CFICertified Flight Instructor. A pilot who holds an instructor certificate and is authorized to provide flight training and endorse student pilots for solo and checkride.Charlie AirspaceClass C airspace surrounding airports with an operational control tower and radar approach control. It requires two-way radio communication and a transponder with Mode C.ChecklistA written or electronic list of tasks and procedures that a pilot must complete during each phase of flight to ensure nothing critical is overlooked for safe operation.Circuit BreakerA resettable electrical protection device in an aircraft that automatically interrupts current flow when it exceeds a safe level, protecting aircraft systems and wiring.Class A AirspaceAirspace from 18,000 feet MSL up to flight level 600. All operations must be under IFR, and pilots must have an instrument rating and ATC clearance.Class B AirspaceControlled airspace surrounding the busiest airports in the country, typically from the surface to 10,000 feet MSL. Requires ATC clearance, radio, transponder, and specific pilot qualifications.Class C AirspaceControlled airspace around airports with an operating control tower and radar service, typically extending from the surface to 4,000 feet AGL. Two-way radio contact is required.Class D AirspaceControlled airspace around airports with an operating control tower, typically from the surface to 2,500 feet AGL. Requires establishing two-way radio communication before entry.Class E AirspaceControlled airspace that is not Class A, B, C, or D. It provides separation for IFR aircraft and generally starts at 700 or 1,200 feet AGL, or at the surface near some airports.Class G AirspaceUncontrolled airspace where ATC does not exercise authority over air traffic. Pilots must still follow VFR weather minimums and right-of-way rules.ClearanceAn authorization from ATC allowing an aircraft to proceed under specified conditions. Pilots must read back the clearance to confirm accuracy.ClimbA flight maneuver in which the aircraft gains altitude. Climb performance depends on excess thrust (power available minus power required) and aircraft weight.CFITControlled Flight Into Terrain. An accident where an airworthy aircraft is unintentionally flown into the ground, water, or an obstacle. It is one of the leading causes of fatal aviation accidents.CockpitThe section of the aircraft where the pilot and crew operate the flight controls, instruments, and avionics. Also called the flight deck in larger aircraft.Common Traffic Advisory Frequency (CTAF)A radio frequency designated for pilots to announce their position and intentions at non-towered airports. It helps maintain situational awareness and traffic separation.Controlled AirspaceAirspace of defined dimensions within which ATC services are provided. It includes Class A, B, C, D, and E airspace. IFR and some VFR flights must follow ATC instructions.Convective SIGMETA weather advisory for severe thunderstorms, tornadoes, embedded thunderstorms, lines of thunderstorms, and hail 3/4 inch or larger. It implies severe or greater turbulence, icing, and low-level wind shear.Coordinated TurnA turn in which the proper amount of rudder is applied to counteract adverse yaw so the ball in the inclinometer stays centered. The occupants feel no lateral force.CrabA crosswind correction technique in which the aircraft's nose is pointed into the wind to maintain a desired ground track. The aircraft's heading differs from its course.Cross-CountryA flight of more than 50 nautical miles from the original point of departure, landing at a different airport. Cross-country time is required for pilot certificate milestones.CrosswindA wind component blowing perpendicular to the aircraft's direction of travel. Pilots use crosswind correction techniques during takeoff, landing, and cruise flight.Carburetor HeatA system that routes heated air to the carburetor to prevent or remove ice formation. Applied when reduced power or high humidity conditions may cause carburetor icing.