Senior aircraftman
Senior aircraftman (SAC) or senior aircraftwoman (SACW)[1] is a rank in the Royal Air Force, ranking between leading aircraftman and senior aircraftman technician (SAC(T)) (although SACs in non-technical trades progress directly to corporal) and having a NATO rank code of OR-2. The rank, which is non-supervisory, was introduced on 1 January 1951. The rank badge is a three-bladed propeller.
Senior aircraftman (technician)
From March 2005, SACs in technical trades who had attained the Operational Performance Standard were promoted to Senior aircraftman technician SAC(T) and given a new badge of rank, consisting of the three-bladed propeller inside a circle. This new rank was introduced, to distinguish airmen trained to work unsupervised from those who were not, and is equivalent to the old junior technician rank.