We see this on a regular basis with farm equipment. The farmer gets a loan to buy the equipment, the lender files an lien. The farmer pays off the loan, but the lender never releases the lien. It is not hard to clear up 95% of the time (particularly if the lender is a bank). However, we have had a loan at a local bank that had been bought out two or three times. It took some time to get to the right person. But I agree the lien must be released before I would buy the plane. You are doing the seller and yourself a BIG favor.