Indicated airspeed

    Args:
        msg (String): 28 bytes hexadecimal message (BDS60) string

    Returns:
        int: indicated airspeed in knots

def ias60(msg):
    """Indicated airspeed

    Args:
        msg (String): 28 bytes hexadecimal message (BDS60) string

    Returns:
        int: indicated airspeed in knots
    """
    d = hex2bin(data(msg))

    if d[12] == '0':
        return None

    ias = bin2int(d[13:23])    # kts
    return ias