Douglas DC-4

Design and development

The name "DC-4" had already been used for a prototype 52-seat precursor that first flew in 1935, but did not enter production and later became known as the DC-4E (to distinguish it from the DC-4 per se). The DC-4E had been rejected by airlines, following proving flights by United Airlines; it had become obvious that the design was too inefficient and unreliable to operate economically and partner airlines – United, American Airlines, Eastern, Pan American and TWA – recommended a lengthy list of changes. Douglas integrated the new requirements into an entirely new, smaller design, the DC-4A, with a simpler fuselage, Pratt & Whitney R-2000 Twin Wasp engines, and a single fin and rudder (rather than the tri-fin tail of the DC-4E). However, the tricycle landing gear and unpressurized cabins of the precursor were retained.

With the entry of the United States into World War II, in December 1941, the United States Army Air Forces took over the provisional orders for the airlines and allocated them the designation C-54 Skymaster. The first C-54 flew from Clover Field in Santa Monica, California, on 14 February 1942.

To meet military requirements, the first production aircraft had four additional auxiliary fuel tanks in the main cabin, which reduced the passenger seats to 26. The following batch of aircraft was the first built to military specifications, and was designated C-54A and built with a stronger floor and a cargo door with a hoist and winch. The first C-54A was delivered in February 1943. With the introduction of the C-54B in March 1944, the outer wings were changed to hold integral fuel tanks, allowing two of the cabin tanks to be removed; this allowed 49 seats (or 16 stretchers) to be fitted. The C-54C was a hybrid for Presidential use; it had a C-54A fuselage with four cabin fuel tanks and the C-54B wings with built-in tanks to achieve maximum range.

The most common variant was the C-54D, which entered service in August 1944, essentially a C-54B with more powerful R-2000-11 engines. With the C-54E the last two cabin fuel tanks were moved to the wings, which allowed more freight or 44 passenger seats.

In total, 1,163 C-54s (or R5D in US Navy service) were built for the United States military between 1942 and January 1946 and another 79 DC-4s were built after the war. A later variant, with more powerful Merlin engines allowing it to fly over 40% faster, was built in Canada as the Canadair North Star.

Operational history

The DC-4/C-54 proved to be a popular and reliable type, with 1,245 being built between May 1942 and August 1947, including 79 postwar DC-4s. Several remain in service as of 2022.

Douglas continued to develop the type during the war in preparation for a return to airline use when peace returned. Sales of new aircraft had to compete against 500 wartime ex-military C-54s and R5Ds which came onto the civilian market, many of which were converted to DC-4 standard by Douglas. DC-4s were a favorite of charter airlines such as Great Lakes Airlines, North American Airlines, Universal Airlines, and Transocean Air Lines. In the 1950s, Transocean (Oakland, California) was the largest civilian C-54/DC-4 operator.

Douglas produced 79 new-build DC-4s between January 1946 and August 9, 1947, the last example being delivered to South African Airways. Pressurization was an option, but all civilian DC-4s (and C-54s) were built unpressurized.

A total of 330 DC-4s and C-54s were used in the Berlin Airlift, which made them one of the most numerous types involved.

Purchasers of new-build DC-4s included Pan American Airways, National Airlines, Northwest Airlines, and Western Airlines in the US, and KLM Royal Dutch Air Lines, Scandinavian Airlines System, Iberia Airlines of Spain, Swissair, Air France, Sabena Belgian World Airlines, Cubana de Aviación, Avianca, Aerolíneas Argentinas, Aeropostal of Venezuela (1946), and South African Airways overseas. Several airlines used new-build DC-4s to start scheduled transatlantic flights between Latin America and Europe. Among the earliest were Aerolíneas Argentinas (1946), Iberia Airlines of Spain (1946), and Cubana de Aviación (1948).

Basic prices for a new DC-4 in 1946–47 were around £140,000-£160,000 (equivalent to £5,793,679 in 2025). In 1960, used DC-4s were available for around £80,000 (equivalent to £1,603,032 in 2025).

As of June 2020, two DC-4s were used for charters in South Africa by the South African Airways Museum Society, with both aircraft (ZS-BMH and ZS-AUB) carrying historical South African Airways livery.

Buffalo Airways of Yellowknife, Northwest Territories continues to operate the type commercially.

Surviving aircraft

Few DC-4s remain in service today.

The last two passenger DC-4s operating worldwide are based in Johannesburg, South Africa. They fly with old South African Airways (SAA) livery. They are ZS-AUB Outeniqua and ZS-BMH Lebombo and are owned by the South African Airways Museum Society and operated by Skyclass Aviation, a company specialising in classic and VIP charters to exotic destinations in Africa.