Which factor is least likely to affect fastener selection?

Fastener selection in aircraft construction is primarily influenced by technical requirements and performance factors related to the structure and the loads it will experience. The choice of fastener is critically dependent on considerations like load-bearing capacity, environmental durability (such as resistance to corrosion or fatigue), and the weight of the components being joined.

Among the listed factors, the color of the aircraft has minimal impact on fastener selection. While aesthetics do play a role in the overall design of the aircraft, they do not significantly influence the structural functionality or performance of fasteners. In contrast, cost, weight, and load and environmental factors directly affect the safety, efficiency, and reliability of the aircraft structure. Therefore, aircraft color is least likely to affect the choice of fasteners used in airframe applications.