AC 43-13 is the reference for acceptable methods, techniques and practices for aircraft wood. With respect to the definition of "aircraft quality" and the drying methods used it refers you to ANC-19, published in 1951 by the Army Navy Commerce Dept. This publication gives information about handing shipping and kiln drying. A wood kiln isn't just an oven to fast bake wood. It gives precise, consistant control over humidity and temperature that is computer controlled. "air drying" is hit and miss depending on weather, location, time of year etc. Improperly dried wood, usually too low humidity, too hot or too fast will result in checking, basically cracks. These would be easy to see. Softer woods such as pine or spruce dry well, hard woods like oak or maple are more difficult as they check or split if dried too quickly. Hemlock dries well but has a bad habit of sometimes twisting or warping but this would be obvious and immediate. People who deal with hemlock in timber frame building say that hemlock dries only two ways, pecfectly straight or perfectly twisted. Use approved species, count the growth rings per inch, use straight grain Quarter Sawn only. You can download AC-43-13-1B/2A for free off FAA website.
