What form is used for a formal request for a contingent duty assignment?

The correct answer is AF Form 3907, which serves as the official document for a formal request for a contingent duty assignment. This form is specifically designed to capture the essential information needed to process a request for temporary duty or assignments that aren't standard. By utilizing AF Form 3907, personnel ensure that their requests are documented appropriately, following the established guidelines and procedures within the Air Force.

AF Form 126 relates to requests for a Leave of Absence, which is not pertinent when discussing contingent duty assignments. AF Form 4856 is utilized for developmental counseling sessions, focusing on performance and conduct, rather than assignment requests. Lastly, AF Form 623 is associated with the Training and Evaluation process, specifically for documenting on-the-job training and qualifications, which does not align with contingent duty assignment requests. Therefore, AF Form 3907 is the specifically designated form for this purpose, ensuring the correct protocol is followed within the Air Force administrative processes.