75 FAA Chart Users’ Guide - IFR Enroute Symbology Airway/Route Types Low and High Enroute Airway Data: Low Enroute Charts Victor Airways LF/MF Airway Uncontrolled LF/MF Airway  RNAV T Route GNSS Required RNAV TK Helicopter Route GNSS Required Preferred Single Direction   $_{$V0}$ Victor Route Unusable Route Segment Direction of Flight Indicator Canadian Routes Only Military Training Routes (MTR) MTRs 5NM or less both sides  of centerline MTRs greater than 5NM either or both sides of centerline  Arrow indicates direction of route See MTR tabulation for altitude range information All IR and VR MTRs are shown except those VRs at or bleow  1500’ AGL CAUTION: Inset charts do not depict MTRs Low and High Enroute Charts ATS Route  Oceanic Route VHF/UHF Data is depicted in Black. LF/MF Data is depicted in Brown. RNAV Route data is depicted in Blue High Enroute Charts Jet Routes  Atlantic Routes  Bahama Routes  RNAV Q Routes  Alaska Q Routes require GNSS and radar surveillance. Within the  CONUS, GNSS or DME/DME/IRU RNAV required, unless other- wise indicated. DME/DME/IRU aircraft require radar surveillance. Preferred Single Direction  Jet Routes Preferred Single Direction  RNAV Q Routes Single Direction ATS Route  Unusable Route Segment Substitute Route  All relative and supporting data See NOTAMs or appropriate shown in brown. publication for specific  information. AIRSPACE INFORMATION