Backcountry Pilot

This is in reference to the directive pertaining to the fuel vent on the early cessna 180's that are on top of the wing .... This is the gospel truth of the matter . I had assumed that there was a MANDANTORY AD issued on this matter. The reason for it has nothing to do with vent leakage when parked .... the issue is inadvertant icing causing a vacuum to vent all fuel from both tanks in flight