Club Procedures for Late Day XC Flights

Friends:
I am trying to learn more about how different clubs with active XC pilots flying privately owned gliders handle the problem of determining "Is everybody back safely?" - before everybody at the airport goes home.

In my club we frequently shut down training operations around 5:00 pm or so and the day's Duty Officer, the instructors and tow pilots will all leave, but we will often still have pilots out on course sometimes as late as 7:00 pm or later. Some pilots have landed back to find that they are the only ones at the airfield. It has happened to me several times.

It seems that there is a real risk of an accident happening on course and nobody realizing it until the next day, or a risk that somebody lands out safely but that fact is not communicated back to the airfield (with a lot of unnecessary worry and confusion).

I'm trying to come up with a procedure that makes sense for our club and so I was hoping people would share here how they try to solve this problem.

Thanks
Roy B.
GBSC Chief Pilot