Splices to a wood spar are prohibited under which locations?

• A. Under an attachment fitting for the wing root, landing gear, engine-mount, lift, or inter-plane strut
• B. At the wing tip
• C. Near the tailplane
• D. In the center of the wing

Answer: (A)

The main point is that wood spars carry significant bending and shear loads, and adding a splice in the stressed area creates a weak point where failure is more likely under load. Splices weaken the continuity of the spar’s grain and can introduce misalignment, moisture traps, and fastener issues, all of which reduce strength where loads are being transferred.

Under an attachment fitting for the wing root, landing gear, engine mount, lift, or inter-plane strut is a critical region because the fitting transmits large forces directly through the spar. If a splice were placed there, the splice would be subjected to the same high stresses as the rest of the spar but with a potential mismatch and discontinuity at the joint, increasing the risk of failure.

Locations such as the wing tip, near the tailplane, or in the center of the wing do not inherently involve the same concentrated loads from a heavy fitting, so the prohibition does not apply in the same way. The key idea is that splices are avoided where fittings impose large, concentrated loads, which is why the stated locations with attachment fittings are prohibited.