Douglas DC-4 C-54B

The C-54B was the third production version of the Douglas C-54 Skymaster, the military derivative of the DC-4 that the United States Army Air Forces had taken over from the civil production line in 1942. It was introduced in March 1944, little more than a year after the first C-54A had been delivered, and it existed for one reason: to carry more fuel without stealing space from the payload. The C-54 and C-54A relied on auxiliary tanks installed inside the cabin, up to four in the C-54A, which took up a large share of the usable volume. In the C-54B the outer wing panels were redesigned to hold integral fuel tanks, which allowed two of those cabin tanks to be removed. Total fuel capacity rose from the C-54A's 3,620 US gallons to 3,740, and the space freed up made room for 49 seats, compared with 26 in the original C-54, or 16 stretchers in the medical evacuation layout.

The powerplant remained the fourteen-cylinder Pratt & Whitney R-2000 Twin Wasp: early aircraft left the factory with the -3 version and later production received the -7. Maximum take-off weight was quoted at about 33,142 kg, up from 30,872 kg for the C-54A. Production was shared between the two Douglas plants building the Skymaster: 100 airframes at Santa Monica, California, and 120 at Chicago, 220 in all, which made it the third most numerous member of the family after the C-54D (380) and the C-54A (252). Thirty of these aircraft were transferred to the United States Navy as the R5D-2; some were converted into staff transports as R5D-2F, later R5D-2Z, and at least one served as a radar and radio testbed with a dorsal mast and wingtip pods. Under the unified designation system of 1962 the surviving R5D-2s became C-54Ps and the VIP conversions VC-54Ps, while R5D-2s and R5D-3s re-engined to approximately C-54G standard became R5D-5s and, from 1962, C-54Ss.

The C-54B was also the direct basis for the versions that followed. The C-54D, the most numerous variant of all, was essentially a C-54B with more powerful R-2000-11 engines; the presidential VC-54C "Sacred Cow", covered in its own entry, was a hybrid that combined a C-54A fuselage with its four cabin tanks and the integral-tank wings of the C-54B to achieve maximum range. Douglas also projected the XC-112 on the C-54B, a pressurised version with Pratt & Whitney R-2800 engines that was never built as such; the single prototype, designated XC-112A and later YC-112A, became the starting point for the DC-6/C-118 family.

The most famous airframe of the series was the 100th production Skymaster, C-54B-1-DO 43-17126 (msn 18326), built at Santa Monica. Roosevelt earmarked it for Winston Churchill and it crossed the Atlantic in the summer of 1944 as an unfurnished shell, becoming the first C-54 in the Royal Air Force under the serial EW999 (the RAF received no further Skymasters until the spring of 1945). The fitting-out was entrusted to Armstrong-Whitworth Aviation at Whitley, Coventry, with furnishings by L. A. Rumbold & Co. of Kilburn: a conference room just inside the entrance door, cubicles for the entourage, a galley with lightweight bone china, the Prime Minister's private stateroom in the tail section, revised electrical, radio and oxygen systems and a built-in stairway, since the cabin floor stood 3 metres above the ground. The installation weighed 6,390 lb (2,898 kg) and left the aircraft with a basic empty weight of 44,680 lb (20,266 kg) and an authorised maximum take-off weight of 73,000 lb (33,112 kg), with fuel for a range of some 4,000 miles. It was ready in November 1944 and carried Churchill, among other journeys, home from Yalta and to Gatow, Berlin, for the Potsdam Conference. The RAF designated its Skymasters as the Skymaster I, a name also applied to the 22 C-54Ds supplied later.

In service the C-54Bs were spread across every theatre of Air Transport Command. The loss record reflects that dispersion: 42-72418 vanished in the China-Burma-India theatre on 17 March 1945 and its wreckage was never found; 42-72385 was destroyed on the ground at Yontan airfield, Okinawa, during a Japanese attack on 24 May 1945; 42-72372 crashed south-east of Biskra in severe turbulence on 18 June 1945 while being ferried from Casablanca to Karachi; and 42-72310 disappeared near Kunming on 4 July 1945. During the Korean War, 42-72457 crashed into the sea just after take-off from Ashiya Air Base, Japan, on 26 September 1950, killing 23 of the 51 on board, while flying the Allied airlift to the peninsula.

After the war hundreds of surplus Skymasters entered the civil market, and the C-54B, with its 49-seat capacity and wing tanks, was especially attractive to airlines. Its civil record also includes some of the worst accidents of the era: the Ruta de Colón of Aerovías Cubanas Internacionales (NC44567) crashed in Spain's Gredos mountains on 6 February 1947, killing 11; Eastern Air Lines Flight 605 dived into the ground near Bainbridge, Maryland, on 30 May 1947 with its 49 passengers and four crew, then the deadliest airliner crash in the United States; China National Aviation Corporation's C-54B N8342C struck Basalt Island, Hong Kong, on 21 December 1948, killing all 35 aboard including Quentin Roosevelt II; and a Curtiss Reid Flying Services C-54B hit the Tête de l'Obiou on 13 November 1950 with 58 people on board. Decades later they were still flying in Africa, Asia and the Caribbean: Avianca Flight 03 (HK-730) at Cartagena on 14 January 1966, Pan African Airlines' N90427 at Port Harcourt on 28 September 1968, Trans Mediterranean Airways' OD-ADI destroyed at Beirut on 28 December 1968, China Airlines' B-1801 shot down near An Loc on 28 November 1974 and African Lux's 9Q-CAM, shot down over Mozambique on 26 November 1977, illustrate a career that reached into the 1980s, with Caribbean Air Cargo's N98AS ditching off St. Croix on 28 March 1981. Sabena also converted one C-54B (c/n 10452) into a swing-tail freighter for Air Congo; it flew for that airline and for Air Zaire from 1966 to 1976, then for Zaire Air Service until 1984 and finally for Kinair Cargo until it crashed in 1988.