Bristol Britannia 253 (Britannia C.1)

The Bristol 253 was the production version of the Britannia designed specifically for the Royal Air Force, which operated it as the Britannia C.1. It derived from the Series 200, a long-range, mixed passenger and freight development that Bristol had intended for the airlines but which found no civil customer; the company eventually offered it to the RAF instead, and the Series 250 became the militarised expression of that concept. The Ministry of Supply contracted for it under specification C176P and, in 1959, RAF Transport Command purchased the whole series: three Model 252s, designated Britannia C.2, and twenty Model 253s, the Britannia C.1. The 252s had originally been ordered with the intention of leasing them to civil charter operators, whereas the 253 was built from the outset to RAF requirements. In this way an aircraft conceived for the Empire routes ended up as the backbone of Britain's strategic airlift.

The essential difference between the two military versions lay in the cabin floor. The 253 received a heavy-duty floor over its full length and provision for rearward-facing seats, an arrangement the RAF preferred for crash safety. It shared with the 252 the large forward freight door that distinguished the Series 250 from the civil 310s, and it was in essence a freighter that could also be used for troop carrying and medical evacuation. Power came from four Bristol Proteus turboprops: the Proteus 765 of 4120 ehp was initially fitted to the 252s, while the military Proteus 255, similar to the 765 and with water-methanol injection to offset the loss of engine performance in certain conditions, delivered 4455 ehp in the 253. The propellers were four-blade de Havilland units. With a maximum payload of 37 400 lb the 253 could cover 4628 statute miles in still air at a cruising speed of 360 mph, and its empty weight was 90 600 lb. Those payload and range figures explain why the RAF valued it so highly over the piston-engined Hastings it replaced.

The RAF was already familiar with the Britannia through the type's troubled development: the second prototype, G-ALRX, had been lost in February 1954 on the mudflats of the Severn Estuary after a failed reduction gear caused an engine fire, and inlet icing problems with the Proteus had delayed the airliner's entry into service with BOAC. By the time the C.1s reached the squadrons those faults had been cured and the aircraft had earned a reputation as a reliable and quiet machine.

The twenty C.1s were given the names of stars, such as Bellatrix, Argo, Vega, Sirius, Regulus, Schedar and Arcturus. The first, XL636 "Argo", was delivered to 99 Squadron at RAF Lyneham, Wiltshire, on 4 June 1959, and 511 Squadron was re-formed at the same station on 15 December 1959 as the second Britannia unit for long-range trooping flights. Both squadrons had previously flown the Handley Page Hastings and, before that, the Avro York. At first each unit operated its aircraft separately; in September 1960 central servicing was introduced and the fleet was pooled, with crews from both squadrons flying any aircraft. In June 1970, when Lyneham became the home of the new Lockheed Hercules, the Britannia fleet moved to RAF Brize Norton in Oxfordshire, which was already accommodating the Short Belfasts of 53 Squadron and the VC10s of 10 Squadron.

For sixteen years the C.1 was the RAF's long-range transport par excellence. It flew the Far East route via El Adem, Aden and Gan to Changi in Singapore, and it carried out the evacuations of British citizens from the Congo in 1960, from Kuwait and Belize in 1961 and from Aden in 1967. That last theatre claimed the only C.1 destroyed in service: on 12 October 1967 XL638 "Sirius" was damaged beyond repair after over-running the runway at RAF Khormaksar. The rest of the fleet survived intact into the mid-1970s, when the perceived easing of the Cold War reduced the need for a large strategic airlift capability. The Britannias were withdrawn in late 1975, 511 Squadron disbanded on 6 January 1976 and the aircraft were stored at RAF Kemble and St Athan.

Far from going to the scrapyard, the ex-RAF machines were eagerly snapped up by freight operators: they had the strengthened floor, the large forward door, relatively low flying hours and economical operating costs. Civilianised and redesignated 253F, they returned to the cargo role for which the Series 200 had been conceived. That second life was not free of accidents: on 30 September 1977 an Interconair 253 crashed on a ferry flight, and on 16 February 1980 a Redcoat Air Cargo 253F came down at Billerica, Massachusetts, shortly after taking off from Boston, with wind shear and turbulence among the contributing factors. In Zaire several airlines kept Britannias on regular cargo flights from N'djili into the early 1990s, thanks to spare parts bought from the Royal Aircraft Establishment and from Cubana. Today XM496 "Regulus" survives complete at Cotswold Airport, Kemble, in RAF colours, while at the Cosford museum a civil 312, G-AOVF, wears Air Support Command livery as XM497 "Schedar".