Site Records

Site Name: RAF Sandwich ('YTM') R3 GCI ROTOR Radar Station

[Source: Nick Catford]

In April 1958, 491 Signals Unit was formerly disbanded and RAF Sandwich closed. The station remained in use on a non-operational basis for RAuxAF FCU summer camps before the site was placed on care and maintenance on 20th September 1958. The GPO retained a presence in the bunker. The domestic site was completely vacated by 1st December 1958 although the married quarters were retained under the control of RAF Manston for use by families of airmen on overseas postings.

In 1959 the ‘1958 plan’ evolved into a system called ‘Plan Ahead’, which was intended to be a centralised and fully automated air defence system to meet the threat from manned bombers. In addition it was to co-ordinate Lightning interceptor aircraft and Bloodhound surface to air missiles, which were coming into service. It was, however, too ambitious for existing computer and data transmission hardware, and with fears of escalating costs ‘Plan Ahead’ was scaled down in 1961 under a scheme known as Linesman/Mediator. This was a comprehensive plan to integrate air defence and air civilian traffic control using common equipment as far as practicable - Linesman referred to the air defence aspects and Mediator to the air traffic control aspects.

In 1961 the now empty bunker was considered as a Sub Regional Control by the Home Office but the Air Ministry would not release it. In 1965 Kent County Council considered the bunker for a County Control but again the Air Ministry refused to release the site so the Council were forced to find an alternative location constructing their purpose built County Control at Springfield to the west of Maidstone in 1967.

In 1965 with increasing civil air traffic the CAA had proposed siting a radar and air traffic control room at Sandwich as part of the Mediator programme. Part of the site was returned to its former civilian owners and the rest of the site (some 17 acres in all) including the bunker was transferred to the Civil Aviation Authority. All the earlier RAF radars had been dismantled; the CAA constructed two new rectangular buildings with gantries for the Marconi T264A primary radars and two circular buildings for the Secondary Surveillance Radar (SSR) these were previously called IFF.

The old GCI radar bunker remained empty and unused. The old RAF guardhouse had its roof removed and new single storey office annexe was built around it; a new operations room built in the new annexe. The new station was commissioned in 1967 controlling the Eastern approach to Heathrow and Gatwick. Although operated by the CAA, the station was also a reporting radar for the Linesman/Mediator system and as such supplied radar information for both military and civilian purposes. At this time the Kent Regional Health Board wanted to use the vacant bunker as a central record store for which it would receive a grant for civil defence purposes. However with the axing of civil defence money in 1968 they abandoned the proposal.

In 1974 following the completion of the final stage of the Linesman/Mediator Air Defence Data Centre and control room at West Drayton the manned CAA ops room at Sandwich was closed. One engineer was retained at Sandwich to service the remotely controlled radars. These radars were subsequently removed and the station vacated prior to 1980.

In 1979, with the issue of RAF Air Staff Requirement (ASR888), the UK Linesman was to be replaced by a new Improved Command and Communication System (ICCS) to be known as IUKADGE (Improved United Kingdom Air Defence Ground Environment). The contract to build the new system was awarded to UKADGE Systems Ltd (UKSL) - a consortium comprising Hughes Aircraft, Marconi and Plessey. The contract was formally signed in September 1981 with a planned completion date of August 1986.

During this period in 1980 the bunker was surveyed as possible replacement for the Dover Castle sub regional control but was found to be in poor condition with the lower floor flooded and it was also considered too small and would have to be extended.

A requirement of IUKADGE was for a GCI in the South East area; both the R3 bunkers at Wartling and Sandwich were both considered but that at Wartling was in too poor condition so Sandwich was selected. The site was reacquired from the CAA by the RAF for £250,000. The bunker was stripped out by the main civilian contractor Arup and two new bunkers were attached to the original ROTOR bunker to provide a protected power supply, fuel and water stores, and plant space. The rebuild of the bunker took two years and was the first of four reconstructed R3 bunker now redesignated R3A to come on line. The building work was the subject of much local complaint, because of damage caused by vibration to buildings surrounding the site, during the installation of sheet piling around the deep excavations. Local residents wanting to complain about the building works were met with blanket denials from the MoD that the work was anything to do with them, whilst the CAA told callers that they no longer owned the site and in any case the work was being carried out by the MoD!

The re-activated site, now to be known as RAF Ash, was not re-fitted with any defence radar and did not become a fully operational radar station, instead it found a role as a reserve CRC (Control & Reporting Centre) with the radar picture and data being piped from other radar stations. The new R3A structure was EMP resistant and the filtered air handling plant enabled operation in an NBC environment.

On the surface two Boxer microwave towers connected Ash to the Air Defence Uniter network. At Swingate, a former CH station (two of its three receiving masts still in use for military communications) also housed until the late 1980s an Ace High tropospheric scatter station and also RAF Ash's UHF transmitter and datalink station. The two circular SSR buildings were retained: one was converted into the new station fire section and the other became a sports pavilion for use by units from RAF Manston.

An instructor demonstrates the intricacies of the Intercept Controllers role to students in the Operational Conversion Unit at RAF Ash

To make more use of the station during peacetime, an OCU (Operational Conversion Unit) for IUKADGE staff was set up on site.

Like the rest of the IUKADGE system, the buildings were ready before the equipment to put in them was. The original finish date of August 1986 was long overshot with the system falling further and further behind schedule because of problems with both hardware and software. The originally specified DEC VAX 785 machines were replaced with the VAX 8650.Software conflicts nearly led at one point to the ditching of the specified language (reused NATO Air defence Ground Environment or NADGE software) in favour of CORAL 66. The rebuilding ground to a halt by the late 1980s owing to the reluctance of the contractors UKSL to proceed any further, alleging non-payment of sums said to be in the region of £50 million!

The MoD attempted to kick-start the project by injecting cash. On 1st April 1991, RAF Manston had assumed administrative responsibility RAF Ash when the first of the IUKADGE installations came on line for training purposes, and the entire system was handed over to RAF control in January1992. Even after this date, UKSL were still very much involved with IUKADGE. Ongoing software problems had to be fixed under warranty. The OCU closed on1st October 1993, the role passing to the School of Fighter Control at Boulmer.

In 1993 RAF Ash became the Ground Environment ‘Operational Evaluation Unit’ testing all new equipment for use in SOC's and CRC's: everything from computers, consoles and paperclips to light strips! Ash continued to operate as a data switching point for the whole system. In 1995 the ADGE OPU was transferred the Air Warfare Centre at RAF Waddington and Ash finally closed on 31st December. The site was sold off by the MOD in 1998

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