上士
Staff sergeant (SSgt) is E-5 in the U.S. Air Force. It ranks above senior airman and below technical sergeant. It is the Air Force's first non-commissioned officer rank, as well as the first Air Force rank to which promotion is attained on a competitive basis. Sergeants, also known in Air Force jargon as "buck sergeant"', no longer exist, having been eliminated in the 1990s after sharing the same pay grade with that of the rank of senior airman (E-4). Staff sergeants are expected to be technically proficient and function as first-line supervisors within a 'work center'. After being selected for promotion, senior airmen must attend Airman Leadership School, which teaches them basic leadership skills and how to write performance reports to become staff sergeant. The term of address is "Staff Sergeant" or "Sergeant". High year of tenure is 20 years as of 2018.