He is very happy as that was his 50 km flight to complete his silver badge.
Does an outlanding count for the 50km silver assignment? I would assume you've got to land at a "proper" place, for instance another gliding base, or at least a field which you declared in advance. Not just a field which happened to be underneath you once you are 50km from home base.
If not, you could just get yourself towed to 5500' altitude, glide in a straight line, find a field when you get below 500' and fulfill the requirement. (Assuming a 1:30 glide angle.) Where's the challenge in that?