There are two supplemental promotion processes; in-system supplemental and senior non-commissioned officer (SNCO) supplemental board. The in-system supplemental is processed monthly in the Weighted Airman Promotion System (WAPS). Eligible staff sergeants (E-5) through senior master sergeants (E-8) whose weighable data changes in their promotion file compete monthly for promotion consideration.
In-system supplemental consideration also applies to Airmen who test after initial selects have been made, deployed Airmen, or anyone who was unable to test during their normal testing window. The SNCO supplemental board is for those members promotion-eligible to E7, E8, and E9. This board is held twice a year. SNCOs may request to meet the supplemental board if they believe they have a valid request according to AFI 36-2502, Enlisted Airman Promotion/Demotion Programs Table 2.5. There are no automatic approvals for supplemental board consideration when an Airman's record did not meet a previous board for which they were eligible.
More detailed information can be found via myPers under “Enlisted” by clicking “Promotion.”