Identify Wood Defects

Question 1

How do you detect decay in a wood structure?

Answer 1

Stick a sharp-pointed knife blade in the suspect area and pry the wood up. If the wood is good, it will come up as a long splinter; if it is decayed it will come up as a chunk

Question 2

Are mineral streaks in a piece of structural aircraft wood reason for rejecting the wood?

Answer 2

No, if there is no evidence of decay in the wood

Question 3

How is compression wood identified?

Answer 3

It has a high specific gravity, it appears to have excessive growth of summer wood, and little contrast between springwood and summerwood

Question 4

Is a hard knot, 1/2-inch diameter allowed if it is in the web of a wing spar?

Answer 4

No, 3/8-inch diameter is in the max allowable knot, and it must meet severe restrictions

Question 5

Are pin knot clusters allowable in aircraft structural wood?

Answer 5

Yes, if they cause only a small effect on grain direction