BC —back course BCA —benefit/cost analysis BCN —beacon BCR —benefit/cost ratio BDAT —digitized beacon data BERM —snowbank(s) containing earth/gravel BLW —below BMP —best management practices BND —bound BOC —Bell Operating Company bps —bits per second BRG —bearing BRI —basic rate interface BRITE —bright radar indicator terminal equipment BRL —building restriction line BUEC —back-up emergency communications BUECE —back-up emergency communications equipment BYD —beyond 

## C 

C/S/S/N —capacity/safety/security/noise CAA —civil aviation authority; Clean Air Act CAAS —Class A Airspace CAB —civil aeronautics board CARF —Central Altitude Reservation Facility CASFO —Civil Aviation Security Office CAT —category; clear-air turbulence CAU —Crypto Ancillary Unit CBAS —Class B airspace CBI —computer based instruction CBSA —Class B surface area CC&O —customer cost and obligation CCAS —Class C Airspace CCC —Communications Command Center CCCC —staff communications CCCH —central computer complex host CCLKWS —counterclockwise CCS7-NI —Communication Channel Signal-7-Network Interconnect CCSA —Class C surface area CCSD —Command Communications Service Designator CCU —Central Control Unit CD —clearance delivery; common digitizer CDAS —Class D Airspace CDR —cost detail report CDSA —Class D surface area CDT —controlled departure time CDTI —cockpit display of traffic information CEAS —Class E Airspace CENTX —central telephone exchange CEP —capacity enhancement program CEQ —council on environmental quality 

CERAP —center radar approach control; combined center radar approach control CESA —Class E surface area CFC —central flow control CFCF —Central Flow Control Facility CFCS —central flow control service CFR —Code of Federal Regulations CFWP —central flow weather processor CFWU —central flow weather unit CGAS —Class G Airspace; Coast Guard Air Station CHG —change CIG —ceiling CK —check CL —centerline CLC —course line computer CLIN —contract line item CLKWS —clockwise CLR —clearance, clear(s), cleared to CLSD —closed CLT —calculated landing time CM —commercial service airport CMB —climb CMSND —commissioned CNL —cancel CNMPS —Canadian Minimum Navigation Performance Specification Airspace CNS —consolidated NOTAM system CNSP —consolidated NOTAM system processor CO —central office COE —U.S. Army Corps of Engineers COM —communications COMCO —command communications outlet CONC —concrete CONUS —Continental United States CORP —private corporation other than ARINC or MITRE CPD —coupled CPE —customer premise equipment CPMIS —consolidated personnel management information system CRA —conflict resolution advisory CRDA —converging runway display aid CRS —course CRT —cathode ray tube CSA —communications service authorization CSIS —centralized storm information system CSO —customer service office CSR —communications service request CSS —central site system CTA —controlled time of arrival; control area CTA/FIR —control area/flight information region CTAF —common traffic advisory frequency CTAS —center-TRACON automation system 

