PARL —parallel  PAT —pattern  PATWAS —Pilots Automatic Telephone Weather Answering  Service  PAX —passenger  PBCT —proposed boundary crossing time  PBRF —pilot briefing  PBX —private branch exchange  PCA —positive control airspace  PCL —pilot controlled lighting  PCM —pulse code modulation  PD —Pilot Deviation  PDAR —preferential arrival and departure route  PDC —pre-departure clearance; program designator code  PDN —Public Data Network  PDR —preferential departure route  PERM —permanent/permanently  PFC —passenger facility charge  PGP —planning grant program  PIC —principal interexchange carrier  PIDP —programmable indicator data processor  PIREP —pilot weather report  PJE —parachute jumping exercise  PLA —practice low approach  PLW —plow/plowed  PMS —program management system  PNR —prior notice required  POLIC —police station  POP —point of presence  POT —point of termination  PPIMS —personal property information management system  PPR —prior permission required  PR —primary commercial service airport  PREV —previous  PRI —primary rate interface  PRM —precision runway monitor  PRN —pseudo random noise  PROC —procedure  PROP —propeller  PSDN —public switched data network  PSN —packet switched network  PSR  —packed snow on runway(s)  PSS —packet switched service  PSTN —public switched telephone network  PTC —presumed-to-conform  PTCHY —patchy  PTN —procedure turn  PUB —publication  PUP —principal user processor  PVC —permanent virtual circuit  PVD —plan view display  PVT —private  RAIL —runway alignment indicator lights  RAMOS —remote automatic meteorological observing  system  RAPCO —radar approach control (USAF)  RAPCON —radar approach control (FAA)  RATCC —Radar Air Traffic Control Center  RATCF —Radar Air Traffic Control Facility (USN)  RBC —rotating beam ceilometer  RBDPE —radar beacon data processing equipment  RBSS —Radar Bomb Scoring Squadron  RCAG —remote communications air/ground facility  RCC —Rescue Coordination Center  RCCC —Regional Communications Control Centers  RCF —Remote Communication Facility  RCIU — Remote Control Interface Unit  RCL — runway centerline; radio communications link  RCLL —runway centerline light system  RCLR —RCL repeater  RCLT —RCL terminal  RCO —remote communications outlet  RCU —remote control unit  RDAT —digitized radar data  RDP —radar data processing  RDSIM —runway delay simulation model  REC —receive/receiver  REIL —runway end identifier lights  RELCTD —relocated  REP —report  RF —radio frequency  RL —General Aviation Reliever Airport  RLLS —runway lead-in lights system  RMCC —Remote Monitor Control Center  RMCF —Remote Monitor Control Facility  RML —radio microwave link  RMLR —RML repeater  RMLT —RML terminal  RMM —remote maintenance monitoring  RMMS —remote maintenance monitoring system  RMNDR —remainder  RMS —remote monitoring subsystem  RMSC —remote monitoring subsystem concentrator  RNAV —area navigation  RNP —required navigation performance  ROD —record of decision  ROSA —report of service activity  ROT —runway occupancy time  RP —restoration priority  RPC —restoration priority code  RPG —radar processing group  RPLC —replace  R  B-9 