def rid_access_data(message_type, msg_tow, msg_horizontal, msg_vertical,
    msg_depth, msg_flag, msg_sats, numofmsg):
    """
    Gets rid of all access data in lists.
    Only trigger and interpolated data remains.
    """
    itt = 0
    while itt < numofmsg:
        if msg_tow[itt] == 0 or message_type[itt] != 'MsgExtEvent':
            message_type.pop(itt)
            msg_tow.pop(itt)
            msg_sats.pop(itt)
            msg_horizontal.pop(itt)
            msg_vertical.pop(itt)
            msg_depth.pop(itt)
            msg_flag.pop(itt)
            itt -= 1
            numofmsg -= 1
        itt += 1
    return numofmsg
