Which rank does not receive an evaluation until completing 24 months of service?

The rank that does not receive an evaluation until completing 24 months of service is Airman Basic (AB). This is because Airman Basic is the entry-level rank in the U.S. Air Force, and members typically complete a significant portion of their initial training and adaptation to military life before formal evaluations are necessary.

During the first two years, the focus is often on acclimatizing to the Air Force environment, learning fundamental duties, and building essential competencies. As a result, the evaluation system is designed to give Airmen time to develop their skills and performance before undergoing formal assessment.

In contrast, Senior Airman (SrA), Technical Sergeant (TSgt), and Chief Master Sergeant (CMSgt) all have established evaluation timelines that require feedback and performance appraisals at various intervals throughout their career progression. This structure ensures that as members gain experience and increase in rank, they receive the necessary guidance and evaluation to promote career development effectively.