The rank of junior technician is only held by airmen in technical trades and by musicians. Airmen in non-technical trades always progressed directly from senior aircraftman to corporal. Junior technicians are qualified to work alone and supervise untrained airmen working within their area of responsibility. The rank was introduced in 1950 as part of a new grading system for technicians, wearing a single point up chevron. In 1964, when the grading system was abolished, JTs were retained, their badge changing to a four-bladed propeller.