John Kerr and I went to see this T-18 at KSEE and advise the widow/owner as to what the overall condition of the AC was and to see what she might get with regard to price .  As she stated the AC has not flown since 1996 and the engine has NOT been started , only turned over by hand by the Son .  The paint is a 4+ and there are a few minor dents in the sheet metal that will require some Bondo to smooth out .  Having been sitting for almost 20 years I explained to her that ALL the rubber parts (tires/tubes, hoses, etc.) would need to be replaced .  I suspect the fuel had not been drained so there is probably some varnish in the tank and carb .  A search would be needed on the engine for AD's and a bore scope of the cylinders would be a good idea .  The interior , IMHO needs a complete replacement (carpet, seat covers , seat belts , etc.) along with a panel upgrade .  I did not notice any cracks in the windshield or canopy .  
I explained to her that there are T-18's out there for sale that are in flying condition going for around 20K+ and that in my opinion, considering the current condition and the work/money required to get the AC back into flying status a fair price "As Is , Where Is"  would be no more than 15K .  This was not a pre sale inspection and should not be taken as such .  It was just to give the owner a ruff idea what they AC might sell for in it's present condition .  There may be more involved to get this AC airworthy .  There were no panels open other than the cowling and a visual access to the cockpit .   It will take a lot of man hours and some $$ to get this AC flying again .  This will not be a quick fix and go fly .  I suspect if someone wants this AC they will take the wing off and trailer the plane home to do the upgrades . 
RB   
