Which rib attachment method is considered improper?

Driving nails through cap strips is considered an improper method for rib attachment due to the potential structural weaknesses it may introduce. When nails are driven through cap strips, they do not provide a strong, secure connection between the wing ribs and the spar or other components. This can lead to issues such as loosening over time or failure under load, compromising the integrity of the aircraft structure.

In contrast, using screws provides a robust connection, as they can be tightened for a secure hold, and their threads engage effectively with the materials involved. Adhesive bonding offers strong, uniform load distribution across the joint, which is ideal in aviation applications where structural efficiency is vital. Similarly, using brackets can enhance the structural connections by providing additional support and stability to the rib attachment, ensuring they withstand the various forces experienced in flight.