What can I do if I want to sell my share of the airplane to another owner? 3 Answers as of September 19, 2011

I am co-owner of an airplane which I told the other owner more than 7 years ago I wanted to sell my share. At one point he told me once his divorce was over he would buy me out. His divorce was over approximately 4 years ago and since then, he refuses to make any concession or deal. Instead, he keeps telling me how much I owe him for past hanger rent and other costs he has incurred, most of which I didn't know anything about prior to him spending the money. I may now have a buyer for my share however the interested party lives on the East Coast. I asked my partner if he is interested in selling his share and he said no. So now until I find a buyer he approves of I am stuck in this co-ownership. Are there any legal obligations I am bound to? I have had no interest nor have I used this airplane since 2003.