Advisory Circular 43.13-1B
Pages 1-1 through 1-37
Airframe and Powerplant Mechanics Airframe Handbook AC 65-15A
Pages 224 through 246
Typical Oral Questions
1. Which species of wood is considered to be the standard when comparing other woods for use in aircraft structure?
2. What is the basic difference between plywood and laminated wood?
The grain in each layer of laminated wood runs in the same direction. The grain in the layers of plywood runs at 90 degrees or 45 degrees to each other.
3. What kind of glue is recommended for making a repair to a wooden aircraft structure?
Synthetic resin glue.
4. How is aircraft plywood prepared for making a compound bend?
The wood is soaked in hot water until it is pliable.
5. How is pressure applied to the glued joint when splicing a wooden aircraft wing spar?
With cabinetmakers parallel clamps.
6. How much pressure must be applied to a glue joint in a piece of softwood to produce a strong joint?
125 to 150 pounds per square inch.
7. What is the correct repair to a wooden aircraft wing spar if the wing-attach bolt holes in the spar are elongated?
Splice in a new section of the spar and drill new holes.
8. What kind of repair is recommended for a hole in the plywood skin of an aircraft wing?
A scarf patch.
9. What is the recommended taper for a splayed patch in a plywood aircraft skin?
5 to 1.
10. What is the recommended taper for a scarf patch in a plywood aircraft skin?
12 to 1.
11. Why should sandpaper never be used when preparing a scarf joint in a wing spar for splicing?
The dust caused by sanding will plug the pores of the wood so the glue cannot get in to form a good bond.
12. What is the largest hole in a plywood wing skin that can be repaired with a fabric patch?
One inch in diameter.
13. Why are light steel bushings often used in bolt holes in a wooden wing spar?
The bushing keeps the spar from being crushed when