What are fixtures used for in aerospace assembly?

Fixtures are primarily utilized in aerospace assembly to position parts accurately. This positioning is crucial during assembly processes because it ensures that components fit together correctly and maintain the necessary alignment for structural integrity and functionality. Accurate positioning helps in achieving the required tolerances and reduces the likelihood of errors during assembly, which can lead to operational issues in the finished aircraft.

While fixtures may play a role in holding components temporarily, their main function is to provide a stable reference point, ensuring that all parts are assembled in the right orientation and at the correct distances from each other. This accuracy is vital for the safety and performance of aerospace structures, where even minor misalignments can have significant consequences.

In contrast, the other options describe functions that do not align with the primary purpose of fixtures. For instance, attaching components permanently is typically serviced by bonding or fastening methods, sealing is achieved through gaskets or sealants, and measuring thickness involves tools such as calipers or micrometers rather than fixtures.