In the United Kingdom to identify individual aircraft, all military aircraft are allocated and display a unique serial number. A unified serial number system, maintained by the Air Ministry (AM), and its successor the Ministry of Defence (MoD), is used for aircraft operated by the Royal Air Force (RAF), Fleet Air Arm (FAA) and Army Air Corps (AAC). Military aircraft operated by government agencies and civilian contractors (for example QinetiQ) are also assigned serials from this system. When the Royal Flying Corps (RFC) was formed in 1912 aircraft were identified by a letter/number system related to the manufacturer. The prefix "A" was allocated to balloons of No.1 Company, Air Battalion, Royal Engineers, the prefix "B" to aeroplanes of No.2 Company, and the prefix "F" to aeroplanes of the Central Flying School.[1] The Naval Wing used the prefix "H" for seaplanes ("Hydroaeroplanes" as they were then known), "M" for monoplanes, and "T" for aeroplanes with engines mounted in tractor configuration.[1] Before the end of the first year a unified serial number system was introduced for both Army and Naval aircraft. The serials are allocated when the contract is placed with the manufacturer or supplier. In an RAF or FAA pilot's personal, service log book, the serial number of any aircraft flown, along with any other particulars, such as aircraft type, flight time, purpose of flight, etc., is entered by the pilot after every flight, thus giving a complete record of the pilot's flying activities and which individual aircraft have been flown.