I used CASA examinations to achieve my Cert IV in Aeroskills. Does the 10-year expiry rule still apply?

Yes. Furthermore, this answer overlooks the bigger problem with the question, in which CASA Part 66 exams are assumed to be acceptable evidence for the theoretical side of assessing Units of Competency. In short, CASA exams should never be used to form part of ASQA compliant assessments in Units of Competency.

See Overview of the Current Situation.