When installing the collar, does it sit flush with the material until fully tightened?

The statement is true. When installing a collar, it is designed to sit flush against the material until fully tightened. This ensures that there is even pressure distributed across the surfaces being joined. A collar that is flush helps to prevent any gaps, which can lead to misalignment or instability in the assembly. Furthermore, having the collar flush minimizes the risk of damage to the components and ensures a secure connection, which is vital for safety and structural integrity in aerospace applications.

In some cases, if the collar were not flush, it could indicate that the installation is incorrect or that there is an issue with the fit of the collar or the material it is being attached to. Ensuring that the collar sits flush before tightening is a key step in the assembly process and aligns with industry best practices for achieving a robust and reliable installation.