| Acronym |
Definition |
| CAA |
Civil Aviation Authority. |
| CAD |
Computer Aided Design. |
| CAM |
Computer Aided Manufacture. |
| CAAFU |
Civil Aviation Authority Flying Unit. |
| CAP |
Civil Air Publication. |
| CAS |
Calibrated Airspeed. |
| CAT |
Clear Air Turbulence. |
| CAVOK |
Ceiling and Visibility OK. |
| CAVU |
Ceiling and Visibility Unlimited. |
| CDI |
Course Deviation Indicator. |
| CDU |
Control Display Unit. |
| CEILING |
Height above ground or water of the base of the lowest layer of cloud below 20,000 feet which covers more than half of the sky. |
| CFI |
Chief Flying Instructor (certified flying instructor in USA). |
| CFRP |
Carbon Fibre Reinforced Plastic |
| CH |
Compass Heading. |
| CHIRP |
Confidential Human Factors Incident Reporting system. |
| C/L |
Centre-Line. |
| CLEARANCE |
Authorization from air traffic control to proceed as requested or instructed. |
| CLOUDS |
commonly-used abbreviations for cloud types :- |
| AC |
altocumulus |
| AS |
altostratus |
| CB |
cumulonimbus |
| CC |
cirrocumulus |
| CI |
cirrus |
| CS |
cirrostratus |
| CU |
cumulus |
| NS |
nimbo stratus |
| SC |
stratocumulus |
| ST |
stratus |
| C of A |
Certificate of Airworthiness. |
| C of E |
Certificate of Experience,C of T, certificate of test. |
| C of G |
centre of gravity (of the aircraft which if suspended, would balance) |
| COM(M) |
Communication(s) |
| C of P |
Centre of Pressure, the point through which the total effect of lift may be said to act on an aeroplane. |
| CPL |
Commercial Pilot's Licence |
| CR or C/R |
Counter-Rotating. |
| CRP |
Compulsory Reporting Point. |
| CRT |
Cathode Ray Tube. |
| CRS Course |
the intended direction of flight in the horizontal plane expressed in degrees of the compass. |
| C/S |
Call Sign. |
| CS |
Constant-Speed. |
| CSU |
Constant Speed Unit. |
| C of T |
Certificate of Test. |
| CTA |
Control Area. |
| CTR |
Control Zone. |
| CW |
Carrier Wave or continuous Wave. |
| CW |
Continuous wave. |
| CZ |
Control Zone (USA). |
