Pilot officer (Plt Off officially in the RAF; PLTOFF in the RAAF and RNZAF; formerly P/O in all services, and still often used in the RAF) is the lowest commissioned rank in the Royal Air Force and the air forces of many other Commonwealth countries. It ranks immediately below flying officer. It normally denotes an officer who has elected to join as a non-graduate direct entrant officer, as those with degrees usually serve only a week at the rank after graduation from the RAF College Cranwell.