You should first get the club paperwork on wing inspections for Vikings. There is very little difference in the basics of inspecting Cruisair wings and Viking wings,and the paperwork will be a big help. The biggest single killer of low wing Bellancas is spar rot caused by leaking tank covers. It is most often the top of the rear spar where the flexing of the tank cover has caused the fabric to leak water in and sit on the spar. It is certainly not limited to that spot but that is a major problem area. A spar splice can cost as much or more than you will probably pay for the whole basket case. The spar butt inspection is also very important. The Viking inspection is not required for a Cruisair, but it is a good idea. Another good method of inspecting the whole spar is sound. Take a plastic hammer with you and start tapping along the spar ,from the tip to the root. Tap in a pattern that goes a little above and below the spar and work your way in. It wont take you long to tell the difference between the unsupported plywood skin and the spar underneath. As you work along the spar any soft spots will sound different and should be investigated further. Wooden boat inspectors have used this method for hundreds of years and it is very effective.(Things to take with you) ice pick, small mirror on an extension,plastic hammer, small flashlight with a flexible neck,big strong flashlight,sharp wood chisel,mallet for chisel. The reason for the chisel is that putting a piece of thin plywood over the spar butt was an old recommended repair for the beginnings of spar cracks. The trouble is that it can hide major cracks or rot that could make the wing unsafe. If it has the plywood covering the butt and the owner wont let you (carefully) remove it for inspection,then you could be buying a good wing or junk._____Grant.