code: def nac_v(msg):
      
      tc = typecode(msg)
  
      if tc != 19:
          raise RuntimeError("%s: Not an airborne velocity message, expecting TC = 19" % msg)
  
      msgbin = common.hex2bin(msg)
      NACv = common.bin2int(msgbin[42:45])
  
      try:
          HFOMr = uncertainty.NACv[NACv]['HFOMr']
          VFOMr = uncertainty.NACv[NACv]['VFOMr']
      except KeyError:
          HFOMr, VFOMr = uncertainty.NA, uncertainty.NA
  
      return HFOMr, VFOMr
docs: Calculate NACv, Navigation Accuracy Category - Velocity
  
      Args:
          msg (string): 28 bytes hexadecimal message string, TC = 19
  
      Returns:
          int or string: 95% horizontal accuracy bounds for velocity, Horizontal Figure of Merit
          int or string: 95% vertical accuracy bounds for velocity, Vertical Figure of Merit