BOAC DC-7C G-AOIC taking off from Manchester UK in April 1958 for a non-stop flight to New York (Idlewild) (later JFK)Swissair DC-7C in 1961DC-7CF freighter of BOAC in 1961 converted with forward and rear freight doors
TheDouglas DC-7 is a retired American airliner built by theDouglas Aircraft Company from 1953 to 1958. A derivative of theDC-6, it was the last major piston engine-powered passenger aircraft made by Douglas, being developed shortly after the earliest jet airliner—thede Havilland Comet—entered service and only a few years before the jet-poweredDouglas DC-8 first flew in 1958. Larger numbers of bothDC-7B andDC-7C variants were also built, with a handful of aircraft converted to cargo hauling or fire-fighting after their commercial transport days had passed.
Unlike other far more successful propeller-driven Douglas aircraft, such as theDC-3 and DC-6, no examples of the DC-7 remain in service as of 2020.[1]
American Airlines revived the designation when they requested an aircraft that could fly across theUnited States coast-to-coast non-stop in about eight hours. (Civil Air Regulations then limited domestic flight crews to 8 hours' flight time in any 24-hour period.[4][5]) Douglas was reluctant to build the aircraft until American Airlines presidentC. R. Smith ordered 25 at a total price of $40 million, thus covering Douglas' development costs.[6]
The DC-7 wing was based on that of theDC-4 and DC-6, with the same span; the fuselage was 40 inches (100 cm) longer than theDC-6B. Four eighteen-cylinderWright R-3350 Duplex-Cyclone Turbo-Compound engines provided power.[7] The prototype flew in May 1953 and American received their first DC-7 in November, inaugurating the first non-stop east-coast-to-west-coast service in the country (unrealistically scheduled just under the eight-hour limit for one crew) and forcing rivalTWA to offer a similar service with itsSuper Constellations. Both aircraft frequently experienced inflight engine failures, causing many flights to be diverted. Some blamed this on the need for high-power settings to meet the national schedules, causing overheating and failure of the engines' power recovery turbines.[8]
The DC-7 was followed by theDC-7B with slightly more power and optional fuel tanks over the wing in the rear of the engine nacelles (selected by Pan Am and South African Airways), each carrying 220 US gallons (833 L; 183 imp gal).South African Airways used this variant to fly Johannesburg to London with one stop. Pan Am's DC-7Bs started flying transatlantic in summer 1955, scheduled 1 hr 45 min faster than theSuper Stratocruiser from New York to London or Paris.
Early DC-7s were purchased only by U.S. carriers. European carriers could not take advantage of the small range-increase of the early DC-7, so Douglas released an extended-range variant, theDC-7C (Seven Seas) in 1956. Two 5 ft (1.5 m) wingroot inserts added fuel capacity, reducedinterference drag and made the cabin quieter by moving the engines farther outboard; the optional nacelle fuel tanks previously seen on Pan American's and South African's DC-7Bs were made standard. The fuselage, which had been extended over the DC-6Bs with a 40-inch (100 cm) plug behind the wing for the DC-7 and DC-7B, was lengthened again with a 40-inch plug ahead of the wing to give the DC-7C a total length of 112 ft 3 in (34.21 m).
Since the late 1940sPan Am and other airlines had scheduled a few non-stop flights from New York to Europe, but westward non-stops against the prevailing wind were rarely possible with an economic payload. TheLockheed Super Constellation and DC-7B that appeared in 1955 could occasionally make the westward trip, but in summer 1956 Pan Am's DC-7C finally started doing it fairly reliably.BOAC was forced to respond by purchasing DC-7Cs rather than wait on the delivery of theBristol Britannia. The DC-7C found its way into several other overseas airlines' fleets, includingSAS, which used them on cross-polar flights to North America and Asia. The DC-7C sold better than its rival, theLockheed L-1649A Starliner, which entered service a year later,[9] but sales were cut short by the arrival ofBoeing 707 andDouglas DC-8 jets in 1958–60.
Starting in 1959 Douglas began converting DC-7s and DC-7Cs intoDC-7F freighters to extend their useful lives. The airframes were fitted with large forward and rear freight doors and some cabin windows were removed.
The predecessorDC-6, especially the DC-6B, established a reputation for straightforward engineering and reliability. Pratt & Whitney, manufacturer of the DC-6sDouble Wasp engines, did not offer an effective larger engine apart from theWasp Major, which had a reputation for poor reliability.[citation needed] Douglas turned toWright Aeronautical for a more powerful engine. TheDuplex-Cyclone had reliability issues of its own, and this affected the DC-7's service record. Carriers who had both DC-6s and DC-7s in their fleets usually replaced the newer DC-7s first once jets started to arrive. Some airlines retired their DC-7s after little more than five years of service, whereas most DC-6s lasted longer and sold more readily on the secondhand market.
Morten Beyer, an airline executive who participated in the decision to buy second-hand DC-7s atRiddle Airlines (later known as Airlift International), said Riddle became comfortable with buying the DC-7, notwithstanding known engine problems, after seeing its success with carriers likeSwissair that made an effort to "baby" the Wright engine. According to Beyer, many passenger carriers had competed on speed and operated the engine at its limits, where it tended to break down. Riddle apparently was able to operate the DC-7 reliably by similarly babying the engine.[10]
Basic price of a new DC-7 was around $823,308 (£570,000).[11]
Price of a DC-7B was around $982,226 (£680,000) in 1955, rising to $1,184,490 (£820,000) in 1957.[11]
Similarly, the price of a DC-7C was $1,155,560 (£800,000) in 1956, increasing to $1,343,385 (£930,000) by 1958.[12]
Cost of the DC-7F "Speedfreighter" conversion was around $166,112 (£115,000) per aircraft.[12]
First long-range variant with higher gross weight and fuel capacity, with most of the added fuel in saddle tanks in enlarged engine nacelles. (Only Pan Am and South African DC-7Bs had the saddle tanks.) 112 built.
DC-7C Seven Seas
Longer-range variant with non-stop transatlantic capability, improved 3,400 hp (2,500 kW) R-3350 engines and increased fuel capacity mainly in longer wings, 121 built.
Seventeen DC-7s remained on the U.S. registry in 2010,[13] they were used mainly for cargo and asaerial firefightingairtankers. Due to itsengine problems, the DC-7 has not had the same longevity as the DC-6, which is still used by a number of commercial operators.[citation needed]
A DC-7 (N8210H) still owned by Douglascrashed into a school yard in thePacoima area ofLos Angeles, California, following a midair collision withNorthrop F-89J Scorpion52-1870, resulting in the deaths of the four crewmembers aboard the DC-7, the pilot of the Scorpion jet, and three students on the ground.[15][16]
March 5, 1957
AnAmerican Airlines DC-7B (N316AA) on a flight fromIdlewild International Airport (nowJFK Airport) inNew York City toDallas Love Field inDallas, TX suffered failure of the #1 engine. The propeller and nose section detached and struck the fuselage, leading to decompression. The pilot made a successful emergency landing at Memphis; there were no fatalities or injuries. The plane was repaired and returned to service.[17]
June 28, 1957
AnEastern Air Lines DC-7B (N808D) collided with a parked Eastern Air Lines Lockheed L-1049 (N6212C) at Miami International Airport after returning from a training flight. Fuel leaked and both aircraft burned out.[18]
February 1, 1958
Pan Am Flight 70, a DC-7C (N733PA,Clipper Blue Jacket), landed wheels-up atSchiphol Airport as a result of pilot error; all 16 on board survived. The aircraft was repaired and returned to service as a freighter.[19] See also July 26, 1970 below.
March 10, 1958
A DC-7B (N846D) still owned by Douglas crashed at Long Beach, California during a test flight before delivery to Eastern Air Lines.[20]
March 25, 1958
Braniff Flight 971, a DC-7C (N5904), crashed shortly after takeoff fromMiami while attempting to return after an engine caught fire. Nine passengers out of 24 people aboard died in the accident.[21]
ASabena DC-7C (OO-SFA) crashed nearCasablanca–Anfa Airport during the attempted landing. All nine crewmembers and 52 of the 56 passengers died.[22]
September 24, 1959
TAI Flight 307, a DC-7C, crashed atBordeaux airport with the loss of 54 lives. After takeoff, the aircraft failed to gain altitude and collided with trees 3 km (1.9 mi) from the start of the takeoff.
November 16, 1959
National Airlines Flight 967, a DC-7B on a flight fromTampa, Florida, toNew Orleans, crashed into theGulf of Mexico. All 42 occupants perished. Although sabotage was suspected, no definite cause of the crash was determined due to a lack of evidence. The aircraft was owned by Delta Air Lines.[23]
February 26, 1960
AlitaliaFlight 618, a DC-7C (I-DUVO), crashed atShannon Airport, Ireland, shortly after takeoff following a loss of altitude while making a left turn with 34 fatalities out of 52 passengers and crew. No cause was established for this accident.[24]
Northwest Orient Airlines Flight 1-11, a DC-7C (N292), ditched off Polillo Island, Philippines due to failure of the number two engine and fire; one person (out of 58 on board) died when the number two propeller separated and penetrated the fuselage.[25]
February 18, 1961
A Pan Am DC-7CF (N745PA) struck a mound of earth short of the runway in Stuttgart while attempting an ILS approach, shearing off the undercarriage and #1 engine. The pilots retained control and were able to climb away, then make a belly landing at Nurnberg airport. The aircraft was written off.[26]
November 1, 1961
APanair do Brasil DC-7C (PP-PDO) flying fromSal toRecife crashed into a hill about 2.7 km (1.7 mi) short of the runway at Recife. Forty-five passengers and crew out of the 88 persons aboard lost their lives. The accident was attributed topilot error.[27][28]
Northwest Airlines Flight 292, a DC-7C (N285) with 7 crew and 95 passengers,[30] made a successful water landing inSitka Sound just before 1 p.m. local time after struggling with propeller problems for 45 minutes[31] while operating as a military charter flight betweenMcChord Air Force Base andElmendorf Air Force Base. The plane stayed afloat for 24 minutes after coming to rest in the water, giving the occupants ample time to evacuate into life rafts with only 6 minor injuries reported. All passengers and crew were quickly rescued by U.S. Coast Guard ships.[32] The cause was an overspeeding propeller when the blower section on engine number two failed.
Eastern Air Lines Flight 663 crashed a few minutes after takeoff fromJohn F. Kennedy Airport in New York after taking evasive action to avoid a possible collision with another airliner (Pan Am Flight 212, a Boeing 707). All 84 passengers and crew died.
December 7, 1968
A North American Aircraft Trading DC-7C (VR-BCY) crashed during approach toUli Airstrip following triple engine failure during a relief flight, killing all four crew.[33]
June 5, 1969
A Swedish Red Cross DC-7B (SE-ERP) was shot down by a Nigerian Air Force MiG-17 and crashed at Eket, Nigeria, killing all four crew. The aircraft was operating a supply flight from Fernando Po (now Bioko) to Biafra.[34]
July 26, 1970
An ARCO ferry flight of a DC-7CF (VR-BCT), from Kinshasa suffered an explosive failure of the #3 engine. The pilots succeeded in making a belly landing on 2 engines (engine #4 having been inoperable for the entire flight), however the plane was damaged beyond repair. This aircraft had previously crashed in 1958.[35]
October 2, 1970
A Spantax DC-7C (EC-ATQ) was written off at Barajas Airport.[36]
December 31, 1972
Professional Baseball playerRoberto Clemente and 4 others in a chartered DC-7 died when the planecrashed shortly after takeoff from San Juan, Puerto Rico. Only parts of the fuselage and the body of pilot Jerry Hill were recovered. The cause was traced to maintenance and pilot errors.[37]
June 21, 1973
A Skyways International DC-7C (N296) crashed in theEverglades six minutes after takeoff fromMiami International Airport, apparently caused by an onboard fire and/or severe turbulence. Three crew members, the sole occupants, died. The aircraft was on lease to Warnaco Incorporated.[38]
March 3, 1974
A Douglas DC-7C/F (EI-AWG) operating an Aer Turas Teo charter flight from Dublin landed atLuton Airport on runway 08 just after midnight but failed to achieve reverse thrust. Normal braking application also was ineffective and the emergency pneumatic brakes were applied. All main wheel tires burst. The aircraft overran the runway and continued over the steep bank at the eastern perimeter finally coming to rest in soft ground 90 metres beyond. The situation had also been made worse by an inadvertent application of forward thrust by the crew in trying to achieve reverse thrust. Three of the six passengers and two of the four crew were injured. The badly damaged aircraft was written off.[39]
October 4, 1976
An Emirates Air Transport DC-7CF (TZ-ARC) struckMount Kenya due to a premature descent, killing the four crew.[40]
September 12, 1977
A Safe Air Cargo DC-7BF (N6314J) crashed on climbout fromYakutat Airport after an engine lost power and caught fire, killing the four crew. 14 CFR 91 subpart D was revised in the wake of this accident.[41]
September 6, 1978
An Advance Aviation Inc. DC-7CF (N244B) was being used to smuggle marijuana when it crashed near Farmerville, Louisiana due to pilot error, killing one of six on board. Thirty-five bales of marijuana were recovered from the wreckage.[42]
June 22, 1979
A Go Transportation DC-7CF (N357AL) crashed on climbout from Barstow Airport due to overloading and loss of engine power (caused by improper 100octane fuel), killing one of six crew.[43]
September 14, 1979
A Butler Aircraft Inc. DC-7 (N4SW) transporting company employees toMedford, Oregon, crashed on the crest of Surveyor Mountain nearKlamath Falls, Oregon. The crash, which claimed the 12 occupants aboard, was attributed to the crew's decision to undertake a night flight at low altitude.
1980
An Aero Services Corp. DC-7CF (N8219H) was shot down and crashed in Colombia during a smuggling flight.[44]
July 27, 1980
A Lambda Air Cargo DC-7CF (CP-1291) burned out on the ground at Trujillo Airport.[45]
November 28, 1980
A Central Air Service DC-7B (N816D) crashed nearPecos Municipal Airport, Texas, soon after takeoff killing the pilot and co-pilot onboard. The plane entered a steep 90° left bank after takeoff, descended fast with the no. 2 prop feathered and crashed in a field.[46]
October 9, 1986
A T&G Aviation DC-7C (N5903) ditched off Dakar due to engine problems, killing three of four crew.[47]
December 8, 1988
A T&G Aviation DC-7CF (N284) was shot down by a SAM-7 missile fired by thePolisario Front andcrashed in theWestern Sahara, killing the five crew. A second T&G DC-7 (N90984) was also hit, losing an engine, but was able to land safely. Polisario soldiers thought the aircraft were Moroccan C-130s.[48][49]
c/n 44285"Charlie 21" – DC-7 on static display at Iliff Preschool inDenver, Colorado. It was installed in 1971 and serves as a kindergarten classroom.[52][53]
Empty weight: 72,763 lb (33,005 kg) *Operating weight empty: 78,890 lb (35,780 kg)
Max takeoff weight: 143,000 lb (64,864 kg) *Maximum landing weight: 109,000 lb (49,000 kg)
Fuel capacity: 7,824 US gal (6,515 imp gal; 29,620 L) in eight wing tanks; oil capacity 246 US gal (205 imp gal; 930 L)
Powerplant: 4 ×Wright R-3350-988TC18EA1-2 18-cylinder turbo-compound air-cooled radial piston engines, 3,400 hp (2,500 kW) each for take-off at sea level
2,800 hp (2,100 kW) in low blower at sea level
2,850 hp (2,130 kW) in low blower at 4,300 ft (1,300 m)
1,900 hp (1,400 kW) maximum cruise in low blower at 14,800 ft (4,500 m)
1,800 hp (1,300 kW) maximum cruise in high blower at 24,400 ft (7,400 m)
Propellers: 4-bladedHamilton-Standard Hydromatic 34E60-345, 14 ft 0 in (4.27 m) diameterconstant-speed fully-feathering reversible propellers
Performance
Maximum speed: 406 mph (653 km/h, 353 kn) rated power in high blower at 22,700 ft (6,900 m)
Cruise speed: 346 mph (557 km/h, 301 kn) recommended at 21,600 ft (6,600 m) and 110,000 lb (50,000 kg) gross weight
^Breffort, Dominique.Lockheed Constellation: From Excalibur to Starliner, Civilian and Military Variants. Paris: Histoire and Collecions, 2006.ISBN2-915239-62-2
^Beyer, Morten S. (2009).Flying Higher. Bloomington, Indiana: Trafford Publishing. pp. 108–109.ISBN978-1-4251-6652-6.
^Aircraft Accident Report: Douglas DC-7C, N285 Northwest Airlines, Inc. Ditching in Sitka Sound, Alaska October 22, 1962. Washington, D.C.: Civil Aeronautics Board. 19 September 1963. p. 1.
^"DC-7 Ditches In Sea Near Sitka; All Safe".The Seattle Daily Times. 22 October 1962.
^Sims, Ward T. (23 October 1962). "102 Saved As Plane Ditches".Seattle Post Intelligencer.
Germano da Silva, Carlos Ari César. "Buraco negro."O rastro da bruxa: história da aviação comercial brasileira no século XX através dos seus acidentes 1928–1996 (in Portuguese). Porto Alegre: Edipucrs, Second edition, 2008.ISBN978-85-7430-760-2.
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Colombia
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Rhodesia Flown by civilian sanctions busterJack Malloch
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