Aviation Maintenance Technician Series Airframe textbook, Vol. 1 ASA Pages 175–185
Aviation Maintenance Technician Airframe Handbook FAA-H-8083-31 Vol. 1 FAA Chapter 6
Advisory Circular 43.13-1B FAA Pages 1-1–1-37
1. Which species of wood is considered to be the standard when comparing other woods for use in aircraft structure?
Sitka spruce.
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 the nut on the attachment bolt is tightened.
14. How long should a glue joint be kept under pressure when splicing a wooden aircraft wing spar?
For at least seven hours.
15. Are mineral streaks in a piece of structural aircraft wood reason for rejecting the wood?
No, if there is no evidence of decay in the wood.
16. Which area of a wooden aircraft wing spar must not contain any splice?
There must be no splice under wing-attach fittings, landing gear fittings, engine mount fittings, or lift and interplane strut fittings.
17. How is compression wood identified?
It has a high specific gravity, it appears to have an excessive growth of summer wood, and little contrast between the spring wood and the summer wood.
18. What is done to a splice in a wooden aircraft wing spar to strengthen the splice?
Reinforcing plates are glued to both sides of the splice.
19. Why must abrupt changes in the cross-sectional area of a wooden structural member be avoided?
Abrupt changes in the cross-sectional area of a structural member concentrate stresses and can cause failure.
1. Explain to the examiner the correct way to repair a wing spar that has an elongated bolt hole in its root end.
2. Install a scarf patch in a damaged piece of aircraft plywood.
3. Inspect a piece of wood for evidence of dry rot. Explain to the examiner what should be done if dry rot is found.
4. Make a scarf splice to a piece of wing rib cap strip material. Reinforce the splice to get maximum strength.
5. Inspect a piece of wing spar material to determine if the grain deviation is within the limits allowed for aircraft wood.
6. Properly mix a batch of resin glue and explain to the examiner the correct way to apply this glue to the wood when making a repair to aircraft wood structure.
7. Given several pieces of wood, examine them for condition and for meeting the specifications for aircraft structural wood.
8. Inspect a wooden aircraft structure to determine whether or not it is in an airworthy condition.
9. Inspect a plywood aircraft structure for evidence of delamination of the plywood or for the failure of the glue joint between the skin and the underlying structure.
10. Explain to the examiner the correct way of repairing a piece of aircraft structure that has been glued with casein glue, when the glue has deteriorated.