(91 Signals Unit) and RAF Benbecula (71 Signals Unit) in the Outer Hebrides, both of which were downgraded to reporting posts which feed data into the UKASACS. Together, the two CRCs processed information which was provided continuously by reporting posts and civilian radars, producing an overview of all aircraft operating within UK airspace, known as the Recognised Air Picture (RAP). Information would also be communicated via digital data-links to neighbouring NATO countries, Airborne Early Warning (AEW) & other aircraft, ground units and ships. Fighter controllers at Buchan also provided tactical control of air-defence aircraft during peacetime Quick Reaction Alert (QRA) interceptions, during training and in the event of war. In 1994 Buchan was home to Nos 170 and 487 Signals Unit and the CRC. As part of a major upgrade of RRH sites around the UK the MOD began a programme titled HYDRA IN 2020 to install new state of the art communications buildings, radar towers and bespoke perimeter security. Closure and downgrading Throughout the remainder of the station's lifetime, its role was gradually sidelined in favour of the Control Reporting Centre at RAF Neatishead. In May 2000 the Ministry of Defence announced the downgrading of RAF Buchan from a manned station to a remote radar head and that RAF Boulmer in Northumberland and RAF Neatishead in Norfolk, would continue to operate the surveillance and control system. The measure resulted in the loss of 55 civilian jobs and the transfer of over 200 RAF personnel from Buchan. Around 92 military and civilian personnel were expected to remain to operate the remote radar head. Buchan ceased to be a RAF station on 1 September 2004 and the operational part of the station was downgraded and renamed Remote Radar Head Buchan. Manned operations formally ceased at RAF Buchan on 26 November 2004 and the domestic site was officially downsized on 31 March 2005. Post-closure Buchan continues to operate as a Remote Radar Head, inputting radar data to the UK Air Surveillance and Control System (UKASACS). The separate domestic accommodation site, located in nearby Boddam, was sold by the Ministry of Defence to a private developer. In 2009 the Officers' Mess was converted into the four star Buchan Braes Hotel. A large part of the domestic site is now home to an Army Cadet Force unit. See also Improved United Kingdom Air Defence Ground Environment – UK air defence radar system in the