The Royal Air Force (RAF) operates several stations throughout the United Kingdom and overseas. This includes front-line and training air bases, support, administrative and training stations with no flying activity, unmanned airfields used for training, intelligence gathering stations and an early warning radar network. The list also includes RAF stations operated by the United States Visiting Forces, former RAF stations now operated by defence contractor QinetiQ on behalf the Ministry of Defence (MOD) and air weapons ranges operated by the MOD. Overseas, the RAF operates airfields at four Permanent Joint Operating Bases (PJOBs) which are located in British Overseas Territories. RAF stations and MOD airfields in the UK Royal Air Force RAF front-line operations are centred on seven main operating bases (MOBs): RAF Coningsby, RAF Marham and RAF Lossiemouth (Air Combat) RAF Waddington (Combat Intelligence, Surveillance Target Acquisition and Reconnaissance) RAF Brize Norton (Air Transport) RAF Benson and RAF Odiham (Support Helicopter Force, operating under Joint Helicopter Command) Operations are supported by numerous other flying and non-flying stations, with activity centred at RAF Honington which coordinates Force Protection, and RAF Leeming and RAF Wittering which have a support enabler role. Stations such as RAF College Cranwell, RAF Valley and RAF Shawbury form part of the UK Military Flying Training System, which is dedicated to training aircrew for all three UK armed services. Specialist ground crew training takes place at RAF Cosford and MOD St Athan. The Control and Reporting Centre (CRC) at RAF Boulmer is tasked with compiling a Recognised Air Picture of UK airspace and providing tactical control of the Quick Reaction Alert Force. Boulmer is supported by a network of eight Remote Radar Heads (RRHs) spread the length of the UK. Ministry of Defence Several former RAF stations are still owned by the Ministry of Defence (MOD) and are operated by defence contractor QinetiQ in the test and evaluation role. The main facility is MOD Boscombe Down, which still has a significant RAF presence. A small number of former RAF stations remain in MOD ownership even though they are used by the RAF in the relief landing ground (RLG) role, flying by Volunteer Gliding Squadrons or other training purposes. They are described as airfields and are typically unmanned. List of sites British Army facilities at Aldergrove and Leuchars are listed in recognition of the RAF retaining an operational airfield at each site. RAF stations operated by the United