8/15/19 3/15/07 12/31/20 AIM 7110.65R CHG 2 Abbreviation/ Acronym Meaning TD ........ Time Difference TDLS ...... Tower Data Link System TDWR ..... Terminal Doppler Weather Radar TDZ ....... Touchdown Zone TDZE ...... Touchdown Zone Elevation TDZL ...... Touchdown Zone Lights TEC ....... Tower En Route Control THL ....... Takeoff Hold Lights TIS ........ Traffic Information Service TIS − B...... Traffic Information Service − Broadcast TLS ....... Transponder Landing System TPP........ Terminal Procedures Publications TRSA ...... Terminal Radar Service Area TSO ....... Technical Standard Order TWIB ...... Terminal Weather Information for Pilots System UA ........ Unmanned Aircraft UAS ....... Unmanned Aircraft System UAV ....... Unmanned Aerial Vehicle UFO ....... Unidentified Flying Object UHF ....... Ultrahigh Frequency U.S. ....... United States USCG ...... United States Coast Guard UTC ....... Coordinated Universal Time UWS....... Urgent Weather SIGMET VAR ....... Volcanic Activity Reporting VASI....... Visual Approach Slope Indicator VCOA ..... Visual Climb Over the Airport VDA....... Vertical Descent Angle VDP ....... Visual Descent Point VFR ....... Visual Flight Rules VGSI ...... Visual Glide Slope Indicator VHF ....... Very High Frequency VIP ........ Video Integrator Processor VMC ...... Visual Meteorological Conditions V$_{MINI}$ ...... Instrument flight minimum speed, utilized in complying with minimum limit speed requirements for instrument flight VNAV...... Vertical Navigation V$_{NE}$ ....... Never exceed speed V$_{NEI}$ ....... Instrument flight never exceed speed, utilized instead of V$_{NE}$ for compliance with maximum limit speed requirements for instrument flight VOR ....... Very High Frequency Omni − directional Range VORTAC . . . VHF Omni − directional Range/Tactical Air Navigation VOT ....... VOR Test Facility Abbreviation/ Acronym Meaning REIL ....... Runway End Identifier Lights REL ....... Runway Entrance Lights RFM ....... Rotorcraft Flight Manual RLIM ...... Runway Light Intensity Monitor RMI ....... Radio Magnetic Indicator RNAV...... Area Navigation RNP ....... Required Navigation Performance ROC ....... Required Obstacle Clearance RPAT ...... RNP Parallel Approach Runway Transitions RVR ....... Runway Visual Range RVSM...... Reduced Vertical Separation Minimum RWSL...... Runway Status Light SAFO ...... Safety Alerts For Operators SAM....... System Area Monitor SAR ....... Search and Rescue SAS ....... Stability Augmentation System SATR ...... Special Air Traffic Rules SBAS ...... Satellite − based Augmentation System SCAT − 1 DGPS ...... Special Category I Differential GPS SDF ....... Simplified Directional Facility SFL........ Sequenced Flashing Lights SFR ....... Special Flight Rules SFRA ...... Special Flight Rules Area SIAP ....... Standard Instrument Approach Procedure SID ........ Standard Instrument Departure SIGMET .... Significant Meteorological Information SM ........ Statute Mile SMGCS .... Surface Movement Guidance Control System SNR ....... Signal − to − noise Ratio SOIA ...... Simultaneous Offset Instrument Approaches SOP ....... Standard Operating Procedure SPC ....... Storm Prediction Center SPS........ Standard Positioning Service STAR ...... Standard Terminal Arrival STARS ..... Standard Terminal Automation Replacement System STMP ...... Special Traffic Management Program TA......... Traffic Advisory TAA ....... Terminal Arrival Area TAC ....... Terminal Area Chart TACAN .... Tactical Air Navigation TAS ....... True Air Speed TCAS ...... Traffic Alert and Collision Avoidance System TCH ....... Threshold Crossing Height Abbreviations/Acronyms Appendix 3 − 4