Pre-Buy Inspections for Used Fly Babies

I often hear from people looking at buying flying Fly Babies, and asking for what to look for.  This is a summary of my usual advice.

A pre-buy inspection for a Fly Baby should be similar to a pre-buy in any used airplane.  Have an A&P look over the aircraft, and verify the condition of the mechanical elements such as the engine, fuel tank, and any electrical items installed.  Remember that these airplanes are built by amateurs...look for chafing in brake and fuel lines, control and bracing cables, and electrical wires.

The A&P will know how to check the usual aircraft things.  There are two main areas of concern on Fly Babies:  Bracing, and dry rot


Some builders have trouble interpreting the instructions for how the flying-wire attachments set up. As you look at a Fly Baby, ensure they are per the plans. You can get a lot of information on the wire bracing on my Bracing web page.  Study the study this page, and get familiar with how the parts are supposed to go together. Print out the picture that shows the flying wire tab at the axle...funny how there are a lot of airplanes with the tab oriented wrong. It should be aligned with the REAR gear leg.  Keep in mind that mine (in the picture) is about ten degrees off....

Dry Rot

Other thing to look out for is dry rot. Three primary places: In the tail cone just forward of the rudder spar, at the rear spar carry-through in the fuselage, and just in front of the rear spar on the wings.

Checking for rot is easy enough, if you can get to the area...poke it with a sharp pocketknife. If the tip only goes in a little bit, you're fine. But if it penetrates easily, you've got rot.

There should be a small inspection panel under the left side of the horizontal stabilizer, see if you can get a light and a mirror into there to view the bottom inside of the fuselage...that's where most of  the water will pool, if the plane sits out in the rain. You probably can't reach the knife in there to check, but the discoloration should be fairly obvious.

Look on the lower portion of the aft cockpit bulkhead (where your back rests) near the spar-pin points. This is the area that rotted out in one neglected airplane and resulted in the recommendation for the reinforcement plates. The plates or the straps should be there; checking for rot is easy enough.

Checking the aft spars of the wings is a bit harder. You need to essentially fold the wings to get the wing root rib accessible, then you can poke the butt end of the spar. If there's an access hole in the root rib, check just forward of the aft spar.

Airworthiness.Org has a nice article on inspecting wooden structures.

Other Advice

Go to my Advice page for information on problems that other owners have reported.

Questions?  Email Ron Wanttaja .