Brown (P) was a 'co-owner' of an airplane with Herriford who bought the plane with a promissory note secured to Avemco (D). Herriford sold lease time in the airplane to P who had an option to buy an interest once the debt to D was retired. P sent D a letter and tendered the balance ($4,859.93) to D but D refused that payment because Herriford failed to honor the terms of the security agreement; written consent was needed to encumber the plane to any third party. D accelerated the payments, and the entire balance of $5,078.97 was due and payable on or before July 28, 1975, with the extra amount for Vendor’s Single Interest Insurance. Ps did not accept D’s rejection of their offer and reaffirmed that the payoff money was available upon presentation of the mortgage. D then repossessed the plane. D sold the plane for $7000. P sued in conversion and D counterclaimed for interference in a contract. The trial verdict went to D for both the conversion and its counterclaim. No damages were assessed. D moved for a new trial. That was denied. P appealed.