What is an acceptable method to repair elongated bolt holes in a wooden wing spar?

Repairing elongated bolt holes in a wooden wing spar is a critical task that directly impacts the structural integrity and safety of the aircraft. The most acceptable method is to remove the damaged section and splice in a new part. This approach ensures that the integrity of the spar is maintained and that the load distribution is properly managed, preventing further damage or failure in the future.

Using a splice allows for the installation of new material that can better accommodate the structural loads placed on the spar. This method involves carefully cutting out the damaged area, preparing the surrounding surfaces for bonding, and attaching a new piece of wood that matches the original spar's dimensions and characteristics. Properly executed splicing adheres to repair guidelines that ensure compliance with regulatory standards.

Other methods, such as filling the holes with epoxy, may provide a temporary fix, but they do not restore the structural load-bearing capability of the spar. Larger bolts with washers could lead to further elongation of the holes or introduce different stress points that compromise the structure over time. Drilling new holes adjacent to the existing ones might provide a stop-gap solution, but it can weaken the structure and is not a robust repair, as it doesn't address the root cause of the elongation.

In summary, splicing in a new