1-WOOD STRUCTURES (PTS) Questions and Answers

1-WOOD STRUCTURES (PTS) Questions and Answers An assembly of two or more layers of wood that have been glued together with the grains of all layers or laminations approximately parallel (Airframe Handbook Vol 1 p 6-7).​ What is a laminated wood assembly? All gluing operations should be performed above 70 degrees F for proper performance of the adhesive. Higher temperatures shorten the assembly times (Airframe Handbook Vol 1 p 6-12) (AC43.13-1B p 1-6). What effects does room temperature have on gluing wood structures using resin glue? Discoloration could be signs of decay or water penetration (Airframe Handbook Vol 1 p 6-5) (AC43.13-1B p 1-11). Why is it necessary to examine all stains and discoloration of wood carefully? Thick glue lines, air bubbles, and a weak glue joint (Airframe Handbook Vol 1 p 6-12). What is the result of insufficient gluing pressure? Sitka spruce (Airframe Handbook Vol 1 p 6-7) . What species of wood is considered the standard for aircraft structures? A moisture meter (Airframe Handbook Vol 1 p 6-3) (AC43.13-1B p 1-14). During a preliminary inspection of an aircraft, what instrument is used to determine the moisture content of the wood structure? Tapping with light plastic hammer or screwdriver handle, probe area with metal awl or thin-bladed screwdriver (Airframe Handbook Vol 1 p 6-7) (AC43.13-1B p 1-29). What mechanical testing tools can be used to detect defects in the wooden structure? Anytime a reinforcement plate exists that is not feathered out on its ends, a stress riser exists at the ends of the plate and a failure of the primary structure can be expected at that point (Airframe Handbook Vol 1 p 6-6). When installing a reinforcement plate on primary wood structure, why are the ends feathered out? 8-12% (AC43.13-1B p 1-14) (Airframe Handbook Vol 1 p 6-3). When inspecting a wooden structure, what is an acceptable percentage of moisture content? A high percentage of at least 75% of wood fibers evenly distributed over the fractured glue surface (Airframe Handbook Vol 1 p 6-13). During a destructive test of a sample bonded joint, what observation indicates the properties of a good bond? An alternate inspection method is to cut inspection holes in the skin on the aft side of the front spar forward of the rear spar so the fabric can be peeled away from the spar (AC43.13-1B p 1-13). What inspection aid can be used to detect spar compression failures when no access is provided through inspection holes? Circular or elliptical patches (ASA question 8012). What type of patch is preferred when repairing the damaged skin area of a plywood structure? Airframe manufacturer or the FAA (AC43.13-1B p 1-1). Who should be contacted when the replacement of wood structure is replaced with wood substitute or modified woods? So that when the wood member shrinks, the bushings do not protrude and the fittings may be tightened firmly against the member (AC43.13-1B p 1-3). When selecting bushings for repair, why should the bushings be slightly shorter than the wood thickness? Sitka Spruce (Airframe Handbook Vol 1 p 6-7). What species of wood is used as a standard for strength properties? Dry powder texture, dark discoloration and soft spots (Airframe Handbook Vol 1 p 6-5).​ When inspecting wooden structures, what observation would indicate rot?