What is used to cover the heads of the rivets after insertion into the assembly?

The correct answer is rivet tape, which is specifically designed to provide a protective covering over rivet heads after they have been inserted into the assembly. Rivet tape is used to seal the rivets, helping to prevent moisture, dirt, and other environmental elements from penetrating through the holes created by the rivets. This is crucial in aerospace applications where the integrity of the structure must be maintained under various operating conditions.

Using rivet tape can also help with aerodynamics by smoothing out the surface and reducing drag, which is vital in aircraft design. The tape adheres well to the surfaces, ensuring that it remains in place and continues to protect the rivet heads effectively.

Other options, while they sound relevant to sealing or finishing operations, do not specifically fulfill the same purpose as rivet tape. For instance, rivet adhesive and rivet sealant may be used more generally in assembly processes but are not specifically designed for covering rivet heads in the same manner. Rivet caps could imply a different component or method not commonly employed in aerospace assembly for this particular function.