Langford Lodge airfield, which is located close to the village of Crumlin, in County Antrim, is commonly perceived and remembered as an American base in World War Two. Initially though, the site was one of about 50 in the United Kingdom which were developed in 1940/41 by the Ministry of Aircraft Production as Satellite Landing Grounds. SLGs were small, minimally equipped airfields to which new aircraft produced by the factories were flown for temporary storage under the auspices of RAF Maintenance Units prior to their being taken to a particular MU where they were fitted out for use by operational squadrons. One or more SLGs were allocated to each MU and Langford Lodge was one of five in Northern Ireland initially allocated to and used by No 23 MU at RAF Aldergrove. Aircraft storage at Langford Lodge commenced on 9 May 1941 but soft ground conditions quickly caused problems and it was decided to provide tarmac runways. Construction of the runways was well advanced by the end of July that year and RAF aircraft were stored at the site until May, 1942.
 
Meanwhile, although the USA was avowedly at peace prior to 7 December 1941, secret meetings which took place throughout the preceding year between representatives of that country and the UK resulted in an agreed strategy for joint engagement of the Axis powers in the event of the USA joining the war. A decision to construct an aircraft maintenance depot at Langford Lodge to provide for repair of American aircraft operated by British forces in addition to American-operated aircraft was one element of this. It was agreed that the Ministry of Aircraft Production would construct runways, buildings and mains services while the United States Army Air Force would take responsibility for operating the depot. In the event, the USAAF decided that to a large extent the operation of the depot would be subcontracted to the Lockheed Overseas Corporation, a subsidiary of the Lockheed Aircraft Corporation, in what proved to be a series of contracts renewable every 6 months. In February 1942, construction of the air depot commenced, the work being accorded absolute priority over all other construction in Northern Ireland. Large numbers of local people were employed to assist with its construction and subsequent administration and to facilitate commuting to and from the site a new rail track was laid by the Great Northern Railway from Crumlin to a terminus at Gortnagallon, half a mile from the actual airfield.
 
The Air Depot at Langford Lodge was officially activated in July 1942, under the command of Col E W Hill, 8th Air Force Service Command, USAAF. However, it was September before it began to operate as intended, only partially at first because construction of buildings and services was far from complete. One of the first aspects of its planned function to be put into effect was overhaul of Pratt & Whitney, Wright and Allison engines, assembly lines being established in Hangar 7. During October/November, 1942, some B-24 Liberator aircraft of the 8th Air Force's 44th Bomb Group, recently arrived in the UK, were modified at the depot but it was January 1943 before all the buildings in what eventually proved to be merely a first phase of construction were sufficiently complete to allow the depot to be fully operational. Essentially, Langford Lodge was one of four primary air depots in the UK which during the period up to July 1944 when the contractual arrangements with Lockheed were terminated, provided complete logistical, ie supply and service back-up facilities to the USAAF, initially the 8th Air Force and then also the 12th, 9th and 15th Air Forces, albeit less extensively,. The other two, larger, depots were at Burtonwood and Warton in Lancashire but there were links between all three which were formalised by the setting up of a Base Air Depot Area organisation (BADA) in September 1943, at which time Langford Lodge was officially designated the 3rd Base Air Depot. As well as overhauling engines, maintaining and repairing aircraft already in service. a significant function of the BADs was preparing new aircraft for supply to combat units. Bomber aircraft were flown directly to the UK from the USA by the north or south Atlantic ferry routes and normally arrived at Prestwick or Nutts Corner, St Mawgan. St Eval or Valley. Fighter aircraft were shipped to Liverpool or Belfast. Both types were then taken to one or other of the BADs for assembly (if required), inspection and modification for use in the European Theatre of Operations. By 1944 however, Langford Lodge had come to specialise in experimental engineering while Burtonwood and Warton concentrated on proven modifications, a reflection of their much greater size. There was a little-publicised instance of this during May 1944 when Lockheed's Chief Test Pilot, the California-based Tony LeVier was at Langford Lodge assisting the Experimental Engineering Section with tests which succeeded in producing a 'fix' for the Allison engines which had been the cause of persistent problems in P-38 Lightnings at high power settings at moderate to high altitudes. In the process, as LeVier recalled in an article published only months before his death in February 1998, the depot's instrument specialist effectively designed the world's first Mach meter, by adopting a dual manifold pressure indicator to warn pilots when the aircraft's speed was approaching its critical Mach number. The depot also specialised in propeller overhaul and the manufacture of modification kits.
 
Termination of the contract with Lockheed reflected no real shortcomings on the company's part, merely that the combined capacities of Burtonwood and Warton for assembly/modification work had increased sufficiently to enable them to meet the logistical demand in that aspect. In fact, during the period that Lockheed had run the depot, through its subsidiary the Lockheed Overseas Corporation, 3250 aircraft were assembled, 11000 were serviced and 450000 components were overhauled. This was an outstanding achievement, all the more so because the relationship between LOC and the USAAF had not been an easy one, basically because of a few significant differences between the civilian and military ways of doing things. Furthermore, as USAAF Station 597, the depot had been subject to a series of bewildering administrative/organisational changes, being designated or known as, variously, "Scheme Y" Northern Ireland, HQ First Service Area; Langford Lodge Air Depot; 2029th Air Depot (Prov); 403rd Air Depot and 3rd Base Air Depot. In its heyday, about 7000 people had been employed comprising about 1000 military personnel, about 3000 Lockheed staff and about 3000 local civilians, paid for from Lockheed funds. From July 1944 until its closure at the end of July 1945, the base functioned as a Storage and Experimental Station, continuing to do some of the work for which it had previously been responsible and, as the war moved towards a conclusion salvaging increasing numbers of war-weary aircraft. For a few months in 1944, Langford Lodge was also the base for Ferrying Squadrons of the 27*' Air Transport Group. Following its closure in 1945, the airfield was placed in Care and Maintenance until 1952 when it was refurbished and used briefly to accommodate the RAF's No 5 Air Navigation School until its disbandment in January, 1953. Five years later, the airfield and buildings were acquired on behalf of the Martin Baker Company to facilitate development of the company's aircraft ejection seat enterprise. Written by the late Ernie Cromie BEM