Commander Air Force's mid-rank officers' ranks are modelled on those of the Royal Navy, the term wing commander is used as a rank, and this is the equivalent of a lieutenant colonel in the army or a commander in the navy. The rank of wing commander is above that of squadron leader and below that of group captain. In the former Royal Naval Air Service, which was merged with the Royal Flying Corps to form the Royal Air Force in 1918, the pilots held appointments as well as their normal ranks in the Royal Navy, and they wore insignia appropriate to
Heraldic badges of the Royal Air Force former No. 60 Group (Signals) badge; the only difference being the name of the unit was changed and the indentations where the unit number used to be on the main badge was removed. Approval and design of badges extends to all units associated with the Royal Air Force; Regular, Reserve, Auxiliary and Air Training Corps. Over 800 squadron and unit badges, carved from Welsh slate, are set into the floor of the central church of the Royal Air Force, St Clements Danes, London. The first carved badge was placed in the floor by its carver, Madge Whiteman, in 1958. Whiteman