On January 10, 1954 a Comet broke up in mid-air. [179] Dan-Air bought all of the surviving flyable Comet 4s from the late 1960s into the 1970s; some were for spares reclamation but most were operated on the carrier's inclusive tour charters; a total of 48 Comets of all marks were acquired by the airline. ", "On This Day: Comet inaugurates the jet age.". L'incidente provocò la distruzione del velivolo e la morte di tutti i 112 a bordo. [135] Olympic Airways was the only other customer to order the type. [147][148], Aeronautical engineering firms were quick to respond to the Comet's commercial advantages and technical flaws alike; other aircraft manufacturers learned from, and profited by, the hard-earned lessons embodied by de Havilland's Comet. The prototype Comet 3 first flew in July 1954, and was tested in an unpressurised state pending completion of the Cohen inquiry. [110] The fuselage escape hatch cut-outs retained their rectangular shape. [10] A number of unorthodox configurations were considered, ranging from canard to tailless designs;[N 4] All were rejected. [193], The last Comet to fly, Comet 4C Canopus (XS235),[1] is kept in running condition at Bruntingthorpe Aerodrome, where fast taxi runs are regularly conducted. [110] The Comet's Certificate of Airworthiness was revoked, and Comet 1 line production was suspended at the Hatfield factory while the BOAC fleet was permanently grounded, cocooned and stored. The Museum’s exhibit is the fuselage of the first of three Comet 1A airliners built at Hatfield in 1953 for Air France. Besides the 707 and DC-8, the introduction of the Vickers VC10 allowed competing aircraft to assume the high-speed, long-range passenger service role pioneered by the Comet. [28] The Ghost engines allowed the Comet to fly above weather which competitors had to fly through. [103], Prime Minister Winston Churchill, 1954. 8 April 1954: Suid-Afrikaanse Lugdiens (South African Airways) Flight 201, a chartered British Overseas Airways Corporation de Havilland DH.106 Comet 1, departed Rome at 1832 UTC, bound for Cairo. Following closely the design features of the two prototypes, the only noticeable change was the adoption of four-wheel bogie main undercarriage units, replacing the single main wheels. [98] The Comet fleet was immediately grounded once again and a large investigation board was formed under the direction of the Royal Aircraft Establishment (RAE). The earliest production aircraft, registered G-ALYP ("Yoke Peter"), first flew on 9 January 1951 and was subsequently lent to BOAC for development flying by its Comet Unit. The de Havilland Ghost (originally Halford H-2) was the de Havilland Engine Company's second turbojet engine design to enter production and the world's first gas turbine engine to enter airline service.A scaled-up development of the Goblin, the Ghost powered the de Havilland Venom, de Havilland Comet … Before the Elba accident, G-ALYP had made 1,290 pressurised flights, while G-ALYY had made 900 pressurised flights before crashing. [28], The Comet was an all-metal low-wing cantilever monoplane powered by four jet engines; it had a four-place cockpit occupied by two pilots, a flight engineer, and a navigator. Nine additional Comet 3 airframes were not completed and their construction was abandoned at Hatfield. Avon-powered Comets were distinguished by larger air intakes and curved tailpipes that reduced the thermal effect on the rear fuselage. The Certificate … [105] The first pieces of wreckage were discovered on 12 February 1954[106] and the search continued until September 1954, by which time 70 percent by weight of the main structure, 80 percent of the power section, and 50 percent of the aircraft's systems and equipment had been recovered. [165] The Comet 3 was destined to remain a development series since it did not incorporate the fuselage-strengthening modifications of the later series aircraft, and was not able to be fully pressurised. Flight Phase: Takeoff (climb) Flight Type: Scheduled Revenue Flight. %%EOF The Comet 4 was a further improvement on the stretched Comet 3 with even greater fuel capacity. [66] On 22 January 1952, the fifth production aircraft, registered G-ALYS, received the first Certificate of Airworthiness awarded to a Comet, six months ahead of schedule. ), BOAC, and de Havilland. Survivors: Yes. [82][138], In 1959 BOAC began shifting its Comets from transatlantic routes[139] and released the Comet to associate companies, making the Comet 4's ascendancy as a premier airliner brief. This wreckage was from the starboard side of the cabin just above the three front windows. British South American Airways merged with BOAC in 1949. Kodera, Craig, Mike Machat and Jon Proctor. [165] As a flying testbed, it was later modified with Avon RA29 engines fitted, as well as replacing the original long-span wings with reduced span wings as the Comet 3B and demonstrated in British European Airways (BEA) livery at the Farnborough Airshow in September 1958. BOAC's Comet 4s were leased out to Air Ceylon, Air India, AREA Ecuador, Central African Airways,[175] and Qantas Empire Airways;[81][176] after 1965 they were sold to AREA Ecuador, Dan-Air, Mexicana, Malaysian Airways, and the Ministry of Defence. [11][149] While the Comet's buried engines were used on some other early jet airliners, such as the Tupolev Tu-104,[150] later aircraft, such as the Boeing 707 and Douglas DC-8, would differ by employing podded engines held on pylons beneath the wings. Cone of Silence was made into a film in 1960, and Beaty also recounted the story of the Comet's takeoff accidents in a chapter of his non-fiction work, Strange Encounters: Mysteries of the Air (1984). [116] The fuselage frames did not have sufficient strength to prevent the crack propagating. ", "Metal to Metal Bonding – For Aircraft Structures: Claims of the Redux Process. 106 Comet 4C con numero di registrazione SU-ALD, numero di serie 6441 e costruito nel 1960. [102] Comet flights resumed on 23 March 1954. [21], The first prototype DH.106 Comet (carrying Class B markings G-5-1) was completed in 1949, and was initially used to conduct ground tests and brief early flights. [N 20], In responding to the report de Havilland stated: "Now that the danger of high level fatigue in pressure cabins has been generally appreciated, de Havillands will take adequate measures to deal with this problem. 1–4.". [54][55], The Comet was powered by two pairs of turbojet engines buried in the wings close to the fuselage. The wing was drastically redesigned from a 40˚ sweep. The DeHavilland Comet was the first production commercial jet airliner that went into service in 1952. Il 3 luglio 1970, un de Havilland DH.106 Comet 4 operante su tale rotta si schiantò alle pendici boscose del massiccio del Montseny, vicino ad Arbúcies , in Catalogna, Spagna. Fuselage alloys detailed in Directorate of Technical Development 564/L.73 and DTD 746C/L90. [102] The prestigious nature of the Comet project, particularly for the British aerospace industry, and the financial impact of the aircraft's grounding on BOAC's operations, both served to pressure the inquiry to end without further investigation. Hall, Geoffrey de Havilland and Bishop were immediately called to the scene, where the water tank was drained to reveal that the fuselage had ripped open at a bolt hole, forward of the forward left escape hatch cutout. Simons, Graham M. "Comet! BOAC installed 36 reclining "slumberseats" with 45-inch (1,100 mm) centres on its first Comets, allowing for greater leg room in front and behind;[31] Air France had 11 rows of seats with four seats to a row installed on its Comets. The Abell Committee, named after chairman C. Abell, Deputy Operations Director (Engineering) of BOAC, consisted of representatives of the Allegation Review Board (A.R.B. Following its first flight, the special order Comet 4C was described as "the world's first executive jet. The second accident was on 8th April 1954. [140] In 1960, as part of a government-backed consolidation of the British aerospace industry, de Havilland itself was acquired by Hawker Siddeley, within which it became a wholly owned division. [42] The undercarriage could also be lowered by a combination of gravity and a hand-pump. The de Havilland DH.88 Comet is a British two-seat, twin-engined aircraft built by the de Havilland Aircraft Company.It was developed specifically to participate in the 1934 England-Australia MacRobertson Air Race from the United Kingdom to Australia.. Development of the Comet was seen as both a prestige project and an entry into the use of modern techniques. De Havilland DH.106 Comet 1 G-ALYY, 1953. [146] Cunningham likened the Comet to the later Concorde, and added that he had assumed that the aircraft would change aviation, which it subsequently did. ", "The cost of solving the Comet mystery must be reckoned neither in money nor in manpower. [N 16] Professor Natesan Srinivasan joined the inquiry as the main technical expert. [N 21][159] A total of 12 of the 44-seat Comet 2s were ordered by BOAC for the South Atlantic route. [64] Upgraded Avon engines were introduced on the Comet 3,[64] and the Avon-powered Comet 4 was highly praised for its takeoff performance from high altitude locations such as Mexico City. [59], The Comet 1 featured 5,050 lbf (22.5 kN) de Havilland Ghost 50 Mk1 turbojet engines. [98] With the recovery of large sections of G-ALYP from the Elba crash and BOAC's donation of an identical airframe, G-ALYU, for further examination, an extensive "water torture" test eventually provided conclusive results. This artificial feel was the first of its kind to be introduced in any aircraft. It was the last leg of the new … [100][N 18] BOAC also voluntarily grounded its Comet fleet pending investigation into the causes of the accident. [27] Both prototypes could be externally distinguished from later Comets by the large single-wheeled main landing gear, which was replaced on production models starting with G-ALYP by four-wheeled bogies. It was re-assigned to RAE Farnborough as back-up fuselage for water-tank pressure testing, but not used. Le semiali nella parte interna avevano uno spessore maggiore, al fine di alloggiare i 4 motori che prendevano aria da aperture ovali al bordo d'attacco e terminavano in condotti di scarico subito dietro il bordo d'uscita. "Report of the court investigation on the accident to COMET G-ALYV", "B.O.A.C. While these lessons could be implemented on the drawing board for future aircraft, corrections could only be retroactively applied to the Comet. Witnesses observed the wingless Comet on fire plunging into the village of Jagalgori,[92] leading investigators to suspect structural failure. Developed and manufactured by de Havilland at its Hatfield Aerodrome in Hertfordshire, United Kingdom, the Comet 1 prototype first flew in 1949. Smith, Adrian. ", "I don't think it is too much to say that the world changed from the moment the Comet's wheels left the ground. As a result, the Comet was extensively redesigned, with oval windows, structural reinforcements and other changes. [30][60] Two hydrogen peroxide-powered de Havilland Sprite booster rockets were originally intended to be installed to boost takeoff under hot and high altitude conditions from airports such as Khartoum and Nairobi. First accident of a De Havilland Comet was on 10th January 1954. h�bbd``b`*~@�q�`V �o��C� H�^ ��@�D����- �I@��/&F�� .#���k� {� "Comet Service To South America Planned" (News). [72], Prince Philip returned from the Helsinki Olympic Games with G-ALYS on 4 August 1952. [118] Based on these findings, Comet 1 structural failures could be expected at anywhere from 1,000 to 9,000 cycles. The flight engineer, Mr David Walter Stanley Sayer, aged 40, held a British Flight Engineer's Licence endorsed for Comet 4 and DC-7B aircraft. [74], In their first year Comets carried 30,000 passengers. [18] From 1947 to 1948, de Havilland conducted an extensive research and development phase, including the use of several stress test rigs at Hatfield Aerodrome for small components and large assemblies alike. ", GB-High Wycombe: "Dismantlement and relocation of Gate Guardian Comet C2 XK699. Developed and manufactured by de Havilland at its Hatfield Aerodrome in Hertfordshire, United Kingdom, the Comet 1 prototype first flew in 1949. 25 0 obj <>/Filter/FlateDecode/ID[<9506D2B1A765E2F27D2FF7D425D3B6C8><7D0C510DC53E804094FA71E51B9D00C4>]/Index[10 27]/Info 9 0 R/Length 81/Prev 21416/Root 11 0 R/Size 37/Type/XRef/W[1 2 1]>>stream [194] Since the 2000s, various parties have proposed restoring Canopus, which is maintained by a staff of volunteers,[195] to airworthy, fully flight-capable condition. As the aircraft could be profitable with a load factor as low as 43 percent, commercial success was expected. [6] Aviation company de Havilland was interested in this requirement, but chose to challenge the then widely-held view that jet engines were too fuel-hungry and unreliable for such a role. For the 1930s racing aircraft, see, "During the next few years, the UK has an opportunity, which may not recur, of developing aircraft manufacture as one of our main export industries. The Comet design was finalized in 1945, as the British aircraft industry was attempting to establish a commercial aircraft industry post-World War II. Modifications to the interiors allowed the Comet 2s to be used in a number of different roles. It was later determined that the Comet's wing profile experienced a loss of lift at a high angle of attack, and its engine inlets also suffered a lack of pressure recovery in the same conditions. Prins, François. The Dash 8-400 is the most productive turboprop aircraft on the market. [58] However, the Comet's buried engine configuration increased its structural weight and complexity. Two passengers sustained minor injuries, but the aircraft, G-ALYZ, was a write-off. In April 1960, 13 Comets, 19 Britannias and 6 DC-7Cs. Netaji Subhash Chandra Bose International Airport, "Comet Engineering: The Performance of Airframe, Engines, and Equipment in Operational Service. DH106 Comet simulator at The de Havilland Museum, London Colney, UK. Although the fuselage failed after a number of cycles that represented three times the life of G-ALYP at the time of the accident, it was still much earlier than expected. Oakey, Michael, ed. 106 Comet.". While the pilot and air traffic control were both aware of it, the storm did not appear severe enough to restrict flight through it. [185] While painted in BOAC colours, it never flew for the airline, having been first delivered to Air France and then to the Ministry of Supply after conversion to 1XB standard;[185] this aircraft also served with the RAF as XM823. 192 Squadron RAF Comet 2R beyond repair on 13 September 1957, and three Middle East Airlines Comet 4Cs were destroyed by Israeli troops at Beirut, Lebanon, on 28 December 1968. "Preludes and Overtures: de Havilland Comet 1". Cause Mapping Example: Sir Geoffrey de Havilland built the first commercial jet that reached production, the Comet. The Imperial War Museum Duxford has a Comet 4 (G-APDB), originally in Dan-Air colours as part of its Flight Line Display, and later in BOAC livery at its AirSpace building. [143] The Bruntingthorpe Aerodrome also displays a related Hawker Siddeley Nimrod MR2 aircraft. [180], In military service the United Kingdom's Royal Air Force was the largest operator, with the 51 Squadron (1958–1975; Comet C2, 2R), 192 Squadron (1957–1958; Comet C2, 2R), 216 Squadron (1956–1975; Comet C2 and C4), and the Royal Aircraft Establishment using the aircraft. Short take-off and landing capabilities. In November 1965 BOAC retired its Comet 4s from revenue service, while other operators continued commercial passenger flights with the Comet until 1981. Proctor, Jon, Mike Machat and Craig Kodera. [97] Aviation author Bill Withuhn concluded that the Comet had pushed "'the state-of-the-art' beyond its limits. ", This page was last edited on 23 November 2020, at 23:35. The airplane operated on a flight from Algiers-Dar el Beida Airport (ALG) to Tripoli International Airport (TIP). In this model the maximum stress level at the margin of one of the outer row of rivet holes near the corner of the window was almost five times greater than in the areas of skin remote from the windows. [14][19][20] The entire forward fuselage section was tested for metal fatigue by repeatedly pressurising to 2.75 pounds per square inch (19.0 kPa) overpressure and depressurising through more than 16,000 cycles, equivalent to about 40,000 hours of airline service. [29], One of the most striking aspects of Comet travel was the quiet, "vibration-free flying" as touted by BOAC. BOAC flight crew revelled in standing a pen on end and pointing that out to passengers; invariably, the pen remained upright throughout the entire flight. endstream endobj 11 0 obj <> endobj 12 0 obj <> endobj 13 0 obj <>stream [117] A further test reproduced the same results. Comet Lost: Services Suspended. Furthermore, the captain was well-qualified, had considerable experience on this route, and had experience in similar weather conditions. The inquiry concluded that the aircraft had encountered extreme negative G forces during takeoff; severe turbulence generated by adverse weather was determined to have induced down-loading, leading to the loss of the wings. [83][84] Qantas was interested in the Comet 1 but concluded that a version with more range and better takeoff performance was needed for the London to Canberra route. [98][99] With no witnesses to the disaster and only partial radio transmissions as incomplete evidence, no obvious reason for the crash could be deduced. Download the PDF. 36 0 obj <>stream All early Comets were withdrawn from service for accident inquiries, during which orders from British Commonwealth Pacific Airlines, Japan Air Lines, Linea Aeropostal Venezolana, National Airlines, Pan American World Airways, and Panair do Brasil were cancelled. [33] Amenities included a galley that could serve hot and cold food and drinks, a bar, and separate men's and women's toilets. Trischler, Helmuth and Stefan Zeilinger, eds. [162], The Comet 3, which flew for the first time on 19 July 1954, was a Comet 2 lengthened by 15 ft 5 in (4.70 m) and powered by Avon M502 engines developing 10,000 lbf (44 kN). [187][188] In 2012, with the planned closure of RAF Lyneham, the aircraft was slated to be dismantled and shipped to the RAF Museum Cosford where it was be re-assembled for display. On 3 March 1953, a new Canadian Pacific Airlines Comet 1A, registered CF-CUN and named Empress of Hawaii, failed to become airborne while attempting a night takeoff from Karachi, Pakistan, on a delivery flight to Australia. [153], The square-windowed Comet 1 was the first model produced, a total of 12 aircraft in service and test. The Feb 1959 OAG shows eight transatlantic Comets a week out of London with 10 BOAC Britannias and 11 DC-7Cs. [64] The square windows of the Comet 1 were replaced by the oval versions used on the Comet 2, which first flew in 1953, and the skin thickness was increased slightly. [6] Out of all the Brabazon designs, the DH.106 was seen as the riskiest both in terms of introducing untried design elements and for the financial commitment involved. The failure then occurred longitudinally along a fuselage stringer at the widest point of the fuselage (accident report Fig 7). All production Comet 2s were also modified to alleviate the fatigue problems (most of these served with the RAF as the Comet C2), while a programme to produce a Comet 2 with more powerful Avons was delayed. In April, another Comet, this one operated by South African Airways, came apart in midair, again over the Mediterranean. The American jets were larger, faster, longer-ranged, and more cost-effective than the Comet. [50] At its introduction, Comet airframes would be subjected to an intense, high-speed operating schedule which included simultaneous extreme heat from desert airfields and frosty cold from the kerosene-filled fuel tanks, still cold from cruising at high altitude. [137] The Comet 4C had the Comet 4B's longer fuselage and the longer wings and extra fuel tanks of the original Comet 4, which gave it a longer range than the 4B. "Jet Jubilee (Part 1)". The low-mounted engines and good placement of service panels also made aircraft maintenance easier to perform. [126][129] The base price of a new Comet 4 was roughly £1.14 million (£22.97 million in 2016). [113] In 2012 a finite element analysis was carried out to find the stress values in a digital model of the Comet's cabin window loaded to a pressure differential of 8.25 psi. 546 or 746 of which the skin was made and in accordance with the advice I received from my Assessors, I accept the conclusion of RAE that this is a sufficient explanation of the failure of the cabin skin of Yoke Uncle by fatigue after a small number, namely, 3,060 cycles of pressurisation.". [71] In addition to the sales to BOAC, two French airlines, Union Aéromaritime de Transport and Air France, each acquired three Comet 1As, an upgraded variant with greater fuel capacity, for flights to West Africa and the Middle East. ", https://www.baaa-acro.com/sites/default/files/import/uploads/2017/04/G-ALYP.pdf, "Report of the Court of Inquiry into the Accidents to the Comet aircraft G-ALYP on 10 January 1954 and Comet G-ALYY on 8 April 1954", "XS235 - De Havilland DH-106 Comet 4C - United Kingdom - Royal Air Force (RAF) - David Oates", "Milestones in Aircraft Structural Integrity", "Aircraft Accident Report AAR8903: Aloha Airlines, Flight 243, Boeing 737-200, N73711", "De Havilland DH.106 Comet 4C, OD-ADT, MEA – Middle East Airlines. [76] Popular Mechanics wrote that Britain had a lead of three to five years on the rest of the world in jetliners. [182] Pilot error was blamed for the type's first fatal accident, which occurred during takeoff at Karachi, Pakistan, on 3 March 1953 and involved a Canadian Pacific Airlines Comet 1A. With the discovery of the structural problems of the early series, all remaining Comets were withdrawn from service, while de Havilland launched a major effort to build a new version that would be both larger and stronger. This was because in 1945 no turbojet engine manufacturer in the world was drawing up a design specification for an engine with the thrust and specific fuel consumption, that could power an aircraft at the proposed cruising altitude (40 thousand feet), speed, and transatlantic range as was called for by the Type 106. [56] The engines were outfitted with baffles to reduce noise emissions, and extensive soundproofing was also implemented to improve passenger conditions. The first Comet 4B flew on 27 June 1959 and BEA began Tel Aviv to London-Heathrow services on 1 April 1960. [151] Boeing stated that podded engines were selected for their passenger airliners because buried engines carried a higher risk of catastrophic wing failure in the event of engine fire. Built by De Havilland. On 11 March 1943, the Cabinet of the United Kingdom formed the Brabazon Committee, which was tasked with determining the UK's airliner needs after the conclusion of the Second World War. [77][78] A slightly longer version of the Comet 1 with more powerful engines, the Comet 2, was being developed,[79] and orders were placed by Air India,[80] British Commonwealth Pacific Airlines,[81] Japan Air Lines,[82] Linea Aeropostal Venezolana,[82] and Panair do Brasil. 0 The earliest production aircraft designated G-ALYP was loaned to the British Overseas Airways Company and inaugurated the first scheduled overseas flight from London to Johannesburg with fare-paying customers on-board. His licence was issued on 20 August 1969 and was valid until 21 August 1970. [25], The prototype was registered G-ALVG just before it was publicly displayed at the 1949 Farnborough Airshow prior to the start of flight trials. ", From 1944 to 1946, the design group prepared submissions on a three-engined twin-boom design, a three-engined canard design with engines mounted in the rear, and a tailless design that featured a. They ran smoothly and were less noisy than piston engines, had low maintenance costs, and were fuel-efficient above 30,000 ft (9,100 m). A de Havilland DH-106 Comet 1 passenger plane, registered G-ALYP, was destroyed in an accident 16 km S off Elba, Italy. The 2R ELINT series was operational until 1974, when replaced by the Nimrod R1, the last Comet derivative in RAF service. [65], The earliest production aircraft, registered G-ALYP ("Yoke Peter"), first flew on 9 January 1951 and was subsequently lent to BOAC for development flying by its Comet Unit. For VIP transport, the seating and accommodations were altered while provisions for carrying medical equipment including iron lungs were incorporated. El De Havilland DH 106 Comet va ser la primera producció comercial d'un avió de reacció. [166] Only two Comet 3s began construction with G-ANLO, the only airworthy Comet 3, demonstrated at the Farnborough SBAC Show in September 1954. [169] This variant became the Hawker Siddeley Nimrod and production aircraft were built at the Hawker Siddeley factory at Woodford Aerodrome. [62] Comet 1s subsequently received more powerful 5,700 lbf (25 kN) Ghost DGT3 series engines. [50], The Comet's thin metal skin was composed of advanced new alloys[N 13] and was both riveted and chemically bonded, which saved weight and reduced the risk of fatigue cracks spreading from the rivets. "[170], The Comet 5 was proposed as an improvement over previous models, including a wider fuselage with five-abreast seating, a wing with greater sweep and podded Rolls-Royce Conway engines. h�b``�e``2d T��, �b�P�����ê�/ci}(k^������`:[�&��Ma���g0 �� [152] In response to the Comet tragedies, manufacturers also developed various means of pressurisation testing, often going so far as to explore rapid depressurisation; subsequent fuselage skins were of a greater thickness than the skin of the Comet. [191] Comet 4Cs are exhibited at the Flugausstellung Peter Junior at Hermeskeil, Germany (G-BDIW),[192] the Museum of Flight Restoration Center near Everett, Washington (N888WA),[177] and the National Museum of Flight near Edinburgh, Scotland (G-BDIX). [144] In spite of the Comet being subjected to what was then the most rigorous testing of any contemporary airliner, pressurisation and the dynamic stresses involved were not thoroughly understood at the time of the aircraft's development, nor was the concept of metal fatigue. All outstanding orders for the Comet 2 were cancelled by airline customers. The Comet, registered G-ALYY, was under the command of Captain Wilhelm K. Mostert, with First Officer Barent J. Grove, Navigator Albert E. Sissing, Radio Officer Bertram E. Webstock, and Flight …