Abb./Acronym  Definition  TUC  Time of Useful Consciousness  UNICOM  Aeronautical Advisory Communications Stations  UTC Coordinated Universal Time  VFR  Visual Flight Rules  VR  Visual Routs (sectional charts)  VO  Visual Observer  W&B  Weight and Balance  WST  Convective Significant Meteorological Information  Remote Pilot – Small Unmanned Aircraft Systems Study Guide  80 