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

The appropriate method to repair elongated bolt holes in a wooden wing spar is to splice in a new section or replace the entire spar. When bolt holes become elongated, it can compromise the structural integrity of the wing spar. Splicing in a new section can provide additional support and restore the strength necessary for safe operation. This process involves carefully matching wood species and ensuring proper grain orientation to maintain the spar’s strength characteristics.

Replacing the entire spar, while more invasive, guarantees the spar will meet original design specifications and load-bearing capabilities. This method is particularly important in aviation applications, where safety and performance are paramount.

Simply drilling larger holes for larger bolts can lead to even more localized stress and weaken the structure further. Using epoxy to fill the holes lacks the necessary mechanical properties to handle the loads experienced by the spar. Leaving the holes as they are neglects the potential for failure, as elongated holes will negatively affect the load distribution and can lead to catastrophic structural failure. Thus, splicing or replacing the spar is essential for maintaining safety and integrity.