Competition stiffens for promotion to senior master sergeant March 16 While the rate of promotions to senior master sergeant is dropping, the number of airmen seeking a step up continues to grow. (Kemberly Groue/Air Force) Snagging a promotion to Air Force senior master sergeant is becoming even harder, as fewer than 7 percent of eligible airmen made the cut in the latest selection round announced Tuesday. Only 1,194 of 17,107 eligible master sergeants earned a promotion to senior master sergeant this time, for a selection rate of 6.97 percent, according to the Air Force Personnel Center. That’s down from 7.62 percent in February 2020. On average, airmen tapped for senior master sergeant this month have spent more than four years in that grade, and over 18 years in the Air Force.