Acting pilot officer (A/Plt Off) is the lowest commissioned grade in the Royal Air Force, being immediately junior to pilot officer. Unlike other RAF ranks which officers may hold in an acting capacity, acting pilot officer is maintained as a separate grade. It normally denotes an officer who has recently been commissioned and joined as a non-graduate direct entrant. Acting pilot officer is not an actual rank, and A/Plt Off's are later regraded to pilot officer, not promoted.
Although acting pilot officer has a NATO ranking code of OF(D), neither the British Army, Royal Marines nor Royal Navy has an exactly equivalent rank. As acting pilot officers are junior to second lieutenants in the British Army or the Royal Marines and to Royal Navy sub-lieutenants, the rank is the most junior commissioned rank in the British Armed Forces.
On a University Air Squadron, students can apply for the position of acting pilot officer in order to undertake a Senior Student or Flight Commander role, usually four per each UAS. In order to be awarded a Volunteer Reserve commission they have to complete an intensive course run by the Officer and Aircrew Cadet Training Unit at RAFC Cranwell. On graduation, RAFVR Acting Pilot Officers hold a full commission for one year. This can be extended if serving for more than one year in a senior position on squadron or retained if serving the RAF reserves.
Up to 2012, 3 Flying Training School (3FTS) were responsible for the training of UAS APOs. However starting in 2013 OACTU took over the duties of training APOs with a course aligned with the commissioning course of the RAF reserves.
The rank insignia is identical to that of a pilot officer, consisting of a thin blue band on slightly wider black band. This is worn on both the lower sleeves of the tunic or on the shoulders of the flying suit or the casual uniform. RAFVR APOs have a VR marking on their rank slides, either a small brass VR pin mounted on the stipe or embroidered underneath.