Dec. 7, 2017 Air Force releases chief master sergeant 17E9 promotion cycle statistics The Air Force has selected 472 senior master sergeants for promotion to chief master sergeant out of 2,142 eligible for a selection rate of 22.04 percent in the 17E9 promotion cycle. The average overall score for those selected was 486.71. Selectees’ average time in grade was 2.98 years and time in