def txt2alt(txt):
    """Convert text to altitude in ft: also FL300 => 30000. as float"""
    try:
        if txt.upper()[:2] == 'FL' and len(txt) >= 4:
            return 100.0 * int(txt[2:])
        else:
            return float(txt)
    except ValueError:
        return -1000000000.0
