Nigel
It's like anything that you own a share in, if you manage to sell the share before the annual then you simply transfer the liability of any cash calls to the new owner. If you don't sell it, then it's your responsibility to pay your share of the bill.
I guess we'd all like the opportunity of having a fleet of aircraft at our disposal (actually I do ! I'm fortunate enough to have the keys to 4 helicopters in my car 2 Robinson R44's, an Enstrom 480 and a Jet Ranger, and I have access to a 500 too) but the reality is that it's very unlikely a group similar to the one you describe will ever be formed.
My access to aircraft is very healthy because at City Heliport where I am based the various owners are all friendly with each other and we spend time ferrying each other to maintenance etc . I've let my friends use my machine for type ratings and LPC's etc and in return, I get access to their machines too. This is traditionally done on a "no money is exchanged" basis too. However, I will admit its a very, very unique situation but has always worked very very well.
Joel
