Standard regional route transmitting frequencies — Page 46, Lesson 37

Let’s begin with the first entry: RV stands for Rescue Vessel. That’s a ship designated for search and rescue duties. Next, RVA is Radar Vectoring Area — that’s an airspace volume where air traffic control provides radar headings to aircraft, usually for sequencing or separation. RVR is Runway Visual Range. This is a measured value — it tells you how far a pilot can see along the runway from the touchdown zone, reported in metres. It’s critical for low-visibility take-off and landing minima. RVSM is Reduced Vertical Separation Minimum. That’s the programme that allows aircraft to fly with a vertical separation of only 300 metres (1,000 feet) between FL 290 and FL 410, instead of the old 600 metres (2,000 feet). It requires special altimetry equipment and approval. RWY is simply Runway. Now moving to the letter S on its own — S means South or Southern Latitude. In position reports or coordinates, you’ll see it after the latitude value. SA is Sand, used in weather reports for sand as a phenomenon. SALS is Simple Approach Lighting System — a basic row of lights leading to the runway threshold, usually for non-precision approaches. SAN is Sanitary — that’s a message handling or service code, not a flight operation term. SAP means Soon As Possible — used in operational messages to indicate urgency. SAR is Search and Rescue — the entire organisation and effort to locate and aid persons in distress. SARPS stands for Standards And Recommended Practices (ICAO). These are the technical specifications and procedures published by ICAO that member states agree to follow for international aviation. SARSAT is Search and Rescue Satellite Aided Tracking System — a satellite-based system that detects and locates distress signals, part of the international COSPAS-SARSAT programme. SAT is Saturday — a date/time group abbreviation. SATCOM is Satellite Communication — voice or data links via satellite, used over oceanic or remote areas. SB is Southbound — direction of flight along a route. SC is Stratocumulus — a low cloud type, grey and patchy, often with rolls or lumps. SCN is Slot Cancellation message — a message type in the slot allocation system for controlled departure times. SCT means Scattered — in weather reports, it describes cloud cover of 3/8 to 4/8 of the sky. SDBY is Stand By — a request to wait, or a radio mode where the receiver is active but the transmitter is off. SDF is Step Down Fix — a point on an instrument approach where you can descend to a lower altitude, usually after crossing a specific fix. Now we enter a new section: Definitions. The first entry here is SE — South East. SPECIAL is Special meteorological report (in abbreviated plain language). That’s a SPECI — a routine METAR is issued hourly, but a SPECIAL is issued when certain criteria are met, like a sudden change in visibility, wind, or weather. SEB is South Eastbound. SEC is Seconds — the unit of time. SECT is Sector — a portion of airspace or a segment of a route. SPI is Special Position Indicator — a transponder feature that highlights a specific aircraft on radar, often used in identification. SPL is Supplementary flight plan (message type designator) — a message filed after the initial flight plan, adding or changing details. SELCAL is Selective Calling system — a system where each aircraft has a unique four-letter code. The ground station transmits that code, and only the addressed aircraft’s receiver lights up or chimes, so the crew doesn’t have to monitor the frequency continuously. SPOT is Spot wind — a wind forecast for a specific location and altitude, often requested for approach or descent planning. SQ is Squall — a sudden, sharp increase in wind speed lasting at least a minute, often associated with thunderstorms. SEP is September. SER is Service OR Servicing OR Served — a general abbreviation for maintenance or provision of service. Now SH... — that’s Showers, followed by a code for the precipitation type. For example, SHRA is showers of rain, SHSN is showers of snow, SHPL is showers of ice pellets, SHGR is showers of hail, SHGS is showers of small hail and/or snow pellets. You can combine them, like SHRASN — showers of rain and snow. SHF is Super High Frequency (3000 to 30,000 MHz) — used for satellite communications and some radar systems. SEV is Severe — used to qualify icing and turbulence reports, like ‘SEV ICE’ or ‘SEV TURB’. SFC is Surface — usually the Earth’s surface, as in surface wind or surface visibility. SFLOC is Synoptic report of the location of sources of atmospherics — a weather report that gives the position of lightning or static discharge sources. SG is Snow Grains — very small, opaque ice particles, like a frozen drizzle. SGL is Signal. SR is Sunrise. SRA is Surveillance Radar Approach — a non-precision approach where the controller gives you headings and altitude advisories using surveillance radar, but without the precision of a PAR. SRE is Surveillance Radar Element of precision approach radar system — that’s the part of a PAR system that provides lateral guidance, while the precision element provides vertical guidance. SRG is Short Range. SRP is Slot Reference Point — a specific point used in slot allocation for departure timing. SRQ is Slot Request Message — the message you send to request a departure slot. SRR is Search and Rescue Region — the geographical area where a particular SAR authority is responsible. SRY is Secondary — as in secondary radar or a secondary frequency. Now the last block: SS appears twice. First SS is Sandstorm. Second SS is Sunset. SSB is Single Sideband — a mode of radio transmission that uses only one sideband, saving bandwidth and power, common in HF communications. SSE is South South East. SSR is Secondary Surveillance Radar — the radar system that relies on transponder replies from aircraft, giving altitude, identity, and other data, unlike primary radar which just bounces a signal off the aircraft skin. And finally SST — that’s the last entry in this excerpt.