code: def mach60(msg):
      
      d = hex2bin(data(msg))
  
      if d[23] == '0':
          return None
  
      mach = bin2int(d[24:34]) * 2.048 / 512.0
      return round(mach, 3)
docs: Aircraft MACH number
  
      Args:
          msg (String): 28 bytes hexadecimal message (BDS60) string
  
      Returns:
          float: MACH number