Summary
Hardened Aircraft Shelter (Building Number 4112), built sometime between 1987 and 1989 at RAF Alconbury for the United States Air Force. It is one of 13 contemporary shelters built to accommodate the Lockheed TR-1A reconnaissance aircraft with its 103ft (31m) wingspan. Its design was undertaken by the Property Services Agency (PSA) Directorate of Defence Works, based on research undertaken by the New Mexico Engineering Research Institute at the University of New Mexico, with the PSA's Directorate of Civil Engineering Services developing the design to withstand the weapons threat. Detailed designs were produced by Turner Wright and Partners, civil engineers. It was constructed by Fairclough Civil Engineering Limited.
Reasons for Designation
The Hardened Aircraft Shelter (Building Number 4112), built sometime between 1987 to 1989 to accommodate the Lockheed TR-1A Dragon Lady reconnaissance aircraft, is listed at Grade II* for the following principal reasons:
Historic interest:
* as one of a group of buildings at RAF Alconbury specifically constructed as part of the USAF redevelopment of the base to accommodate TR-1A reconnaissance aircraft: a key component of NATO’s strategy to gather intelligence on the Warsaw Pact countries and the only base in Europe to be associated with the use these unique military aircraft;
* it embodies the strong political ties and co-operation that existed between the United Kingdom and United States (‘the special relationship’) throughout the Cold War.
Architectural interest:
* as a particularly important building associated with an internationally significant Cold War airbase, with a design that reflects both a military response to accommodating the wingspan of the TR-1A and NATO’s concerns in the 1980s to harden its bases against first attack;
* as only 13 examples of this type of HAS were built globally, all at Alconbury, they are regarded as rare and unique examples of national and international significance;
* it survives well and retain significant external and internal features, including blast defector fences, personnel doors with entrance telephones, supply/extract ventilation systems, and shelter lighting.
Group value:
* it forms an important group with contemporaneous inter-related infrastructure that supported the deployment of TR-1A reconnaissance aircraft, all of which reflect one of the key themes of the Cold War, the worldwide surveillance and gathering of intelligence by the superpowers, which was Alconbury’s principal role during this period.
History
AIRFIELD
RAF Alconbury began life in early 1938 when the Air Ministry acquired 150 acres of farmland on Alconbury Hill to test its viability as a satellite airfield. After a successful test in May by the Fairey Battles of Number 63 Squadron from nearby RAF Upwood, Little Stukeley landing ground, as it was probably known at the time, was provisionally accepted as Britain’s first satellite airfield on 2 June. Although Battles arrived again on 1 September 1939 with Number 52 Squadron, they left again just six days later, and Alconbury quickly became a satellite airfield to RAF Wyton, Cambridgeshire. The facilities at this time were rudimentary, consisting of a briefing room and bomb stores. However, this changed in 1941, when three runways were laid out, and a watch tower and operations room (listed Grade II) were added, along with around 26 additional aircraft hardstandings and two T2-Type hangars for aircraft maintenance. Numerous pre-fabricated buildings were also erected for accommodation and specialist technical purposes along a unit headquarters.
Alconbury’s long association with the United States Army Air Force (USAAF) commenced in 1942 with the arrival of the 8th Air Forces 93rd Bomb Group with their Consolidated B-24 Liberators. The airfield subsequently filled a variety of roles under the 8th Air Force, including the activation of the 482nd Bomb Group (Pathfinder) on 10 August 1943, the only USAAF group to be activated outside the United States, with a specific role in developing radar and other electronic navigational devices for ‘blind bombing’ and ‘bombing through cloud’.
On the 1 March 1944, Station 547, the Abbots Ripton Strategic Air Depot, built immediately to the east of the airfield, became operational. It consisted of four T2 hangars, technical shops and additional hard standings. A taxi-way was also laid out across the Abbots Ripton road to allow aircraft to pass between the airfield and the depot.
In November 1945, the airfield was handed back to the RAF and taken over by Number 264 Maintenance Unit. On 28 March 1949 Abbots Ripton was placed in care and maintenance, and in 1954 it was administratively combined with RAF Alconbury.
On 1 June 1953, with heightened international tension following several major crises, including the Berlin Blockade (1948-1949) and the Korean War (1950-1953), the airfield was reactivated under the United States Air Force in Europe (USAFE) as one of the bases for the US 3rd Air Force. Major construction work subsequently took place in 1954, including a new 9,000 ft runway, a new control tower and numerous other infrastructure, including hangars and bomb stores for both nuclear and conventional weapons.
From 1959 Alconbury assumed what was to be its principal Cold War role as the home to various reconnaissance squadrons, with the 10th Tactical Reconnaissance Wing with their Douglas RB-66b Destroyer aircraft being the first to arrive in August. The airfield was substantially remodelled between 1977 and 1980, being provided with a new set of bomb proof, hardened structures. Most notable was the construction of 28 Hardened Aircraft Shelters (HAS), built to a standard NATO design, and intended to hold, initially, reconnaissance Phantom aircraft. A series of Squadron Operations and Command Centres were also built along with ‘Hush Houses’.
On 22 February 1983 Alconbury received a pair of Lockheed TR-1A Dragon Lady reconnaissance aircraft, an upgraded version of the very high altitude and long-range surveillance aircraft which was better known as the U-2 ‘spy plane’. The primary function of these aircraft, with their ultra-high technology equipment, was to fill a serious gap in the collection of intelligence, particularly from the Warsaw Pact countries. To manage TR-1A operations, Strategic Air Command (SAC) had activated the 17th Reconnaissance Wing (RW) on 1 October 1982, with the 95th Reconnaissance Squadron (RS) its flying component. It became operational five months later when three more TR1-As arrived out of an eventual dozen. To accommodate aircraft with 103-foot (31m) wingspans, thirteen extra-wide hardened aircraft shelters (Building Numbers 4100 to 4112) were built in the northern section of the airfield at an estimated total cost of some $42,980,900, with a further £13,610,000 spent on new taxiways, engine run-up areas and concrete aprons. To service the electronic components of the reconnaissance aircraft and process the data received, an Avionics and Photography Interpretation Centre (Building Number 210), which is listed Grade II*, was built at a cost of around $18 million, while three combined buildings housing the Physiological Support Division (PSD) and 17th RW Squadron Operations (Building Numbers 199, 200, and 201) were constructed at a total cost of around $12,470,000. Most of the TR-1A project at Alconbury was financed through NATO funding and is believed to have exceeded $134,000,000 when it was completed in 1990. In the same year TR-1A aircraft from Alconbury participated in operation Desert Shield after Iraq's invasion of Kuwait, and Desert Storm to liberate Kuwait.
The supposed end of the Cold War saw the beginning of the end of flying at Alconbury. The TR-1As left in September 1993 and all flying ceased in early 1995, although part of the airfield remained in use by the Americans for communications duties, while other parts were adapted for commercial use as well as a police training centre for Cambridge Constabulary. Alconbury finally closed as a USAFE base in 2022.
The majority of the airfield is currently being developed as Alconbury Weald, a new settlement of around 6,500 homes, with supporting infrastructure and facilities, including shops, schools, health and leisure facilities.
HARDENED AIRCRAFT SHELTER (BUILDING NUMBER 4112)
The deployment of Hardened Aircraft Shelters at United States Air Force (USAF) bases in Europe has its origins in the Arab-Israeli War of 1967, which demonstrated the vulnerability of parked aircraft to bombing and strafing runs. As the USAF believed a Soviet attack, even from conventional weapons, could destroy a significant proportion of its European air power, it instigated a new building programme called the ‘Theater Air Base Vulnerability Evaluation Exercise’ (TAB VEE), which was designed to improve runways and provide shelter for aircraft from the blast and fragmentation of a conventional bomb exploding nearby, but not from a direct hit. Construction of the first generation of TAB VEE aircraft shelters commenced in 1969, and by April 1972 324 had been constructed in Germany, Netherlands, Italy and Turkey. Each shelter, which was assigned with a single fighter aircraft, consisted of concrete walls on three sides and a slightly arched concrete roof. The shelters were initially open at the front, but the design was modified at a later date to include a single sliding door. A second-generation shelter, referred to as a Hardened Aircraft Shelter (HAS) rather than a TAB VEE shelter, was introduced around 1972 following the deployment of F-111 aircraft whose wing spans exceeded the TAB VEE shelter’s openings. A third generation shelter, which saw the replacement of the second generations double Dutch door with an externally mounted door, was introduced in around 1976. At Alconbury, however, the deployment of the Lockheed TR-1A reconnaissance ‘spy’ plane with its 31m (103ft) wingspan prevented it from using the airfield’s existing aircraft shelters, and a new generation of shelters had to be designed and built. As research for large span shelters had already been undertaken at the New Mexico Engineering Research Institute (NMERI) at the University of New Mexico, this work was passed to the Property Services Agency (PSA), who were responsible for the maintenance of buildings and associated installations except for any item supplied and fitted directly by USAF personnel or under USAF arrangement, to see if it could be adapted for the TR-1A. Civil engineers at the PSA Directorate of Works took the design lead whilst the PSA’s Directorate of Civil Engineering Services developed the design to withstand weapons threat. Detailed designs and working drawings for 13 shelters were then produced by consultants Turner Wright and Partners, with the civil engineers Mott, Hay and Anderson developing the mechanical and electrical design. The shelters, the largest in Europe, if not the world, were constructed between 1987 and 1989 by Fairclough Civil Engineering Limited. The loop taxiway, shelter pavements and all other hard standings were completed before work commenced in July 1987 by AR Construction.
Details
Hardened Aircraft Shelter (Building Number 4112), built sometime between 1987 and 1989 at RAF Alconbury for the United States Air Force. It is one of 13 contemporary shelters built to accommodate the Lockheed TR-1A reconnaissance aircraft with its 103ft (31m) wingspan. Its design was undertaken by the Property Services Agency (PSA) Directorate of Defence Works, based on research undertaken by the New Mexico Engineering Research Institute at the University of New Mexico, with the PSA's Directorate of Civil Engineering Services developing the design to withstand the weapons threat. Detailed designs were produced by Turner Wright and Partners, civil engineers. It was constructed by Fairclough Civil Engineering Limited.
MATERIALS: the shelter has a reinforced-concrete foundation and foundation edge beams, a reinforced-concrete arch superstructure with a galvanised steel lining, and steel front and rear doors infilled with concrete. It forms a pair with HAS Building Number 4111 which stands at the opposite side of a Y-shaped hardstanding. Earthen berms planted with trees partly conceal the shelter on its north-west, south-east and south-west sides.
PLAN: the shelter is rectangular on plan, aligned roughly north-east to south-west, and measures 42m wide and 35m long with a maximum height of 10m. On its left-hand side is a single-storey personnel access door.
EXTERIOR: the shelter has a three-centred arched profile in cross section, with the front face of the arch having a continuous 50mm thick steel rebound plate. The double-leaf front doors have 12mm thick armour-plated steel skin on each side and are stabilised by a rolled hollow steel section (RHS) framework. Each leaf is constructed from six prefabricated full-height panels that were welded together on site after being fabricated in Italy. Two rail tracks set within the reinforced-concrete foundation slab allow for the lateral movement of the doors, with the RHS framework transferring an equal amount of weight to each rail. At the rear is a single-leaf sliding door, also of 12mm thick armour-plated steel, through which jet efflux was vented to a blast deflector fence. The doors are operated by rack and pinion gear driven by hydraulic motors located in the mezzanine plant room. On the left-hand side of the shelter there is a single-storey personnel door protected by a reinforced-concrete blast wall and roof. To the right-hand side of the door there is an entrance telephone and to the blast wall's external face there is a steel door concealing a diesel generator refuelling panel. On the roof there are T-shaped ventilators.
INTERIOR: the floor is of exposed reinforced concrete and the walls are of exposed corrugated steel. It retains 13 supply/extract ventilation systems for normal use, dedicated smoke extract and standby generator cooling, and two further systems for vehicle exhaust extraction. The original shelter lighting, a combination of high bay and underwing units, also survives. At the rear left-hand corner of the shelter there is a pair of rooms, one above the other, the lower one being the sensor readiness area, which retains no original equipment, and the upper one a plant room accessed by a metal staircase, which contains an hydraulic power unit for operating the doors.
