code: def roll50(msg):
      
      d = hex2bin(data(msg))
  
      if d[0] == '0':
          return None
  
      sign = int(d[1])    # 1 -> left wing down
      value = bin2int(d[2:11])
  
      if sign:
          value = value - 512
  
      angle = value * 45.0 / 256.0    # degree
      return round(angle, 1)
docs: Roll angle, BDS 5,0 message
  
      Args:
          msg (String): 28 bytes hexadecimal message (BDS50) string
  
      Returns:
          float: angle in degrees,
                 negative->left wing down, positive->right wing down