S  RPZ —runway protection zone  RQRD —required  RRH —remote reading hygrothermometer  RRHS —remote reading hydrometer  RRL —runway remaining lights  RRWDS —remote radar weather display  RRWSS —RWDS sensor site  RSA —runway safety area  RSAT —runway safety action team  RSR —en route surveillance radar  RSS —remote speaking system  RSVN —reservation  RT —right turn; remote transmitter  RT & BTL —radar tracking and beacon tracking level  RTAD —remote tower alphanumerics display  RTCA —Radio Technical Commission for Aeronautics  RTE —route  RTP —regional transportation plan  RTR —remote transmitter/receiver  RTRD —remote tower radar display  RTS —return to service  RUF —rough  RVR —runway visual range  RVRM —runway visual range midpoint  RVRR —runway visual range rollout  RVRT —runway visual range touchdown  RW —runway  RWDS —same as RRWDS  RWP —real-time weather processor  RWY —runway  SD-ROB —radar weather report  SDS —switched data service  SE —southeast  SEL —single event level  SELF —simplified short approach lighting system with  sequenced flashing lights  SFAR-38 —Special Federal Aviation Regulation 38  SFL —sequence flashing lights  SHPO —State Historic Preservation Officer  SIC —service initiation charge  SID — standard instrument departure; station identifier  SIGMET —significant meteorological information  SIMMOD —airport and airspace simulation model  SIMUL —simultaneous  SIP —state implementation plan  SIR —packed or compacted snow and ice on runway(s)  SKED —scheduled  SLR —slush on runway(s)  SM —statute miles  SMGC —surface movement guidance and control  SMPS —sector maintenance processor subsystem  SMS —safety management system; simulation modeling  system  SN —snow  SNBNK —snowbank(s) caused by plowing  SNGL —single  SNR —signal-to-noise ratio, also: S/N  SOAR —system of airports reporting  SOC —service oversight center  SOIR —simultaneous operations on intersecting runways  SOIWR —simultaneous operations on intersecting wet  runways  SPD —speed  SRAP —sensor receiver and processor  SSALF —simplified short approach lighting system with  sequenced flashers  SSALR —simplified short approach lighting system with  runway alignment indicator lights  SSALS —simplified short approach lighting system  SSB —single side band  SSR —secondary surveillance radar  STA —straight-in approach  STAR —standard terminal arrival route  STD —standard  STMUX —statistical data multiplexer  STOL —short takeoff and landing  SUN —Sunday  SURPIC —surface picture  SVC —service  SVCA —service A  SVCB —service B  SVCC —service C  S —south  S/S —sector suite  SA —sand, sanded  SAC —Strategic Air Command  SAFI —semi-automatic flight inspection  SALS —short approach lighting system  SAT —Saturday  SATCOM —satellite communications  SAWR —Supplementary Aviation Weather Reporting Station  SAWRS —Supplementary Aviation Weather Reporting  System  SB —southbound  SBGP —state block grant program  SCC —System Command Center  SCVTS —Switched Compressed Video Telecommunications  Service  SDF —simplified directional facility; simplified direction  finding; software defined network  SDIS —switched digital integrated service  SDP —service delivery point  B-10 