What is a crucial factor in the performance of a repair when patching a hole in aircraft skin?

In the context of repairing a hole in aircraft skin, compatibility with surrounding materials is a critical factor. This consideration ensures that the repair patch adheres properly and maintains the integrity of the aircraft structure. When selecting a patch, it is essential to use materials that can endure similar stress, strain, and environmental conditions as the original aircraft skin. This compatibility helps prevent issues such as corrosion, differential expansion or contraction, and structural weakness, which could compromise the safety and performance of the aircraft.

While factors such as the type of patch material, cost, and size of the surrounding structure are important to consider, they are secondary to ensuring that the materials used in the repair are compatible with the existing skin of the aircraft. Proper compatibility ensures that the patch will bond effectively and help restore the aircraft's structural integrity, making it a key aspect of a successful repair.