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111-543: The de Havilland DH.106 Comet is the world's first commercial jet airliner . Developed and manufactured by de Havilland in the United Kingdom, the Comet 1 prototype first flew in 1949. It features an aerodynamically clean design with four de Havilland Ghost turbojet engines buried in the wing roots, a pressurised cabin , and large windows. For the era, it offered a relatively quiet, comfortable passenger cabin and

222-538: A by-election in March 1935 , at which he was opposed by an Independent Conservative candidate sponsored by Randolph Churchill . In May 1935, he was in effect saying that Germany should have a predominant place in central Europe, so that Britain could be free to pursue her colonial interests without rival. He was a prewar member of the Anglo-German Fellowship . In November 1936 Sandys put forward to

333-709: A capacity of 24 seats. 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. Nevertheless, the British Overseas Airways Corporation (BOAC) found the Type IV's specifications attractive, and initially proposed a purchase of 25 aircraft; in December 1945, when a firm contract was created,

444-426: A combination of gravity and a hand-pump. Power was syphoned from all four engines for the hydraulics, cabin air conditioning , and the de-icing system ; these systems had operational redundancy in that they could keep working even if only a single engine was active. The majority of hydraulic components were centred in a single avionics bay. A pressurised refuelling system, developed by Flight Refuelling Ltd , allowed

555-403: A dedicated station, with a table across from the flight engineer. Several of the Comet's avionics systems were new to civil aviation. One such feature was irreversible, powered flight controls , which increased the pilot's ease of control and the safety of the aircraft by preventing aerodynamic forces from changing the directed positions and placement of the aircraft's control surfaces . Many of

666-528: A different approach and started development of the 787 in 2003 with a new composite frame and more fuel-efficient engines. This would prove to be the smarter choice as the lighter airframe paired with two next generation engines ( Trent 1000 and GEnx ) was much less costly to operate then the quad engine A380. The final blow to the A380 program came when Emirates cancelled a major order in 2018 and left Airbus without enough demand to continue production. It cancelled

777-428: A faster rate of climb further cut flight times. In August 1953 BOAC scheduled the nine-stop London to Tokyo flights by Comet for 36 hours, compared to 86 hours and 35 minutes on its Argonaut (a DC-4 variant) piston airliner. ( Pan Am 's DC-6B was scheduled for 46 hours 45 minutes.) The five-stop flight from London to Johannesburg was scheduled for 21 hr 20 min. In their first year, Comets carried 30,000 passengers. As

888-610: A jet aircraft has confirmed one opinion I had formed after flying as a passenger in the Lancastrian jet test beds, that few, if any, having flown in a jet-propelled transport, will wish to revert to the noise, vibration and attendant fatigue of an airscrew-propelled piston-engined aircraft" The first purpose-built jet airliner was the British de Havilland Comet which first flew in 1949 and entered service in 1952 with BOAC. It carried 36 passengers up to 2500 miles (4000 km) at

999-688: A key role in the creation of the European Movement . He established the United Europe Movement in Britain in 1947 following a speech of his father-in-law, Winston Churchill, in Zurich on 19 September 1946 when Churchill had called for the "European family" to be recreated and provided with "a structure under which it can dwell in peace, in safety and in freedom". In 1947, Joseph Retinger , who had been instrumental in setting up

1110-466: A larger 36-seat version. With no time to develop the technology necessary for a proposed tailless configuration, Bishop opted for a more conventional 20-degree swept-wing design with unswept tail surfaces, married to an enlarged fuselage accommodating 36 passengers in a four-abreast arrangement with a central aisle. Replacing previously specified Halford H.1 Goblin engines, four new, more-powerful Rolls-Royce Avons were to be incorporated in pairs buried in

1221-692: A member of the Consultative Assembly of the Council of Europe from 1950 until 1951. Sandys was elected to parliament once again at the 1950 general election for Streatham and, when the Conservatives regained power in 1951, he was appointed Minister of Supply . For most of his time in that role, his private secretary was Jack Charles. As Minister of Housing from 1954, he introduced the Clean Air Act and in 1955 introduced

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1332-404: A second Comet 1A and never operated the type in commercial service. Both early accidents were originally attributed to pilot error, as overrotation had led to a loss of lift from the leading edge of the aircraft's wings. 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

1443-436: A significantly more-spacious environment. BOAC installed 36 reclining "slumberseats" with 45 in (1,100 mm) centres on its first Comets, allowing for greater leg room in front and behind; Air France had 11 rows of seats with four seats to a row installed on its Comets. Large picture window views and table seating accommodations for a row of passengers afforded a feeling of comfort and luxury unusual for transportation of

1554-616: A smaller fin and rudder since the hazards of asymmetric thrust were reduced. The engines were outfitted with baffles to reduce noise emissions, and extensive soundproofing was also implemented to improve passenger conditions. Placing the engines within the wings had the advantage of a reduction in the risk of foreign object damage , which could seriously damage jet engines. The low-mounted engines and good placement of service panels also made aircraft maintenance easier to perform. The Comet's buried-engine configuration increased its structural weight and complexity. Armour had to be placed around

1665-522: A speed of 450mph (725 km/h). Serious structural problems arose not even two years after entering service and prompted several changes in design. The last original Comet was retrofitted in 1958. Also developed in 1949 was the Avro Canada C102 Jetliner , which never reached production; however, the term jetliner came into use as a generic term for passenger jet aircraft. These first jet airliners were followed some years later by

1776-588: A superior product: American Airlines ordered the pioneering Comet (but later cancelled when the Comet ran into metal fatigue problems), Canadian, British and European airlines could not ignore the better operating economics of the Boeing 707 and the DC-8, while some American airlines ordered the Caravelle. Boeing became the most successful of the early manufacturers. The KC-135 Stratotanker and military versions of

1887-468: A water tank that could be safely configured to increase pressures gradually. 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. The windows were also tested under a pressure of 12 psi (83 kPa), 4.75 psi (32.8 kPa) above expected pressures at

1998-527: The Automatic Direction Finder , which had caused a catastrophic break-up of the aircraft in high-altitude flight. The exact origin of the fatigue failure could not be identified but was localised to the ADF antenna cut out. A countersunk bolt hole and manufacturing damage that had been repaired at the time of construction using methods that were common, but were likely insufficient allowing for

2109-524: The BAC One-Eleven and Douglas DC-9 twinjets ; Boeing 727 , Hawker Siddeley Trident and Tupolev Tu-154 trijets ; and the paired multi-engined Ilyushin Il-62 , and Vickers VC10 . The world-renowned supersonic Concorde first flew in 1969 but proved to be an economical disaster. Only 14 ever entered service, and the last Concorde was retired in 2003. The 1960s jet airliners were known for

2220-621: The Council of Europe and Western European Union until 1972 when he announced his retirement. The next year he was made a member of the Order of the Companions of Honour . In 1974 he retired from parliament and was awarded a life peerage on 2 May. As the title of Baron Sandys was already held by another family, he followed the example of George Brown and incorporated his first name in his title, changing his surname to Duncan-Sandys . He

2331-706: The European League for Economic Cooperation in 1946, approached Sandys, then Honorary Secretary of the UEM, to discuss ways the League and the United Europe Movement might cooperate on questions relating to European integration. They decided to call a small conference of existing organisations working for European unity – the European League for Economic Cooperation, the United Europe Movement,

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2442-646: The Norwegian campaign and was wounded in action; this left him with a permanent limp. His father-in-law gave him his first ministerial post as Financial Secretary to the War Office from 1941 to 1944 during the wartime coalition government. Sandys had been wartime Parliamentary Secretary to the Ministry of Supply . W. A. Robotham who had been in the Ministry as "Chief Engineer of Tank Design" wrote that he

2553-1129: The Nouvelles Equipes Internationales , the European Parliamentary Union , and the European Union of Federalists . This took place in Paris on 20 July 1947 where ELEC, the UEM, the EPU and the EUF agreed to establish the Committee for the Co-ordination of the International Movements for European Unity. The EPU did not however subsequently ratify its participation in the committee but the Nouvelles Equipes Internationales agreed to join. In December 1947,

2664-802: The Sud Aviation Caravelle from France, the Tupolev Tu-104 from the Soviet Union (2nd in service), and the Boeing 707 , Douglas DC-8 and Convair 880 from the United States. National prestige was attached to developing prototypes and bringing these early designs into service. There was also a strong nationalism in purchasing policy, so that US Boeing and Douglas aircraft became closely associated with Pan Am , while BOAC ordered British Comets. Pan Am and BOAC, with

2775-542: The Tupolev Tu-144 , have been superseded. The 1970s jet airliners introduced wide-body (twin-aisle) craft and high-bypass turbofan engines . Pan Am and Boeing "again opened a new era in commercial aviation" when the first Boeing 747 entered service in January 1970, marking the debut of the high-bypass turbofan which lowered operating costs, and the initial models which could seat up to 400 passengers earned it

2886-505: The green belts . He was appointed Minister of Defence in 1957 and quickly produced the 1957 Defence White Paper that proposed a radical shift in the Royal Air Force by ending the use of fighter aircraft in favour of missile technology. Though later ministers reversed the policy, the lost orders and cuts in research were responsible for several British aircraft manufacturers going out of business. As Minister of Defence he saw

2997-711: The secret services , and threatened with prosecution under section 6 of the Official Secrets Act 1920 . Sandys reported the matter to the Committee of Privileges which held that the disclosures of Parliament were not subject to the legislation, though an MP could be disciplined by the House. The Official Secrets Act 1939 was enacted in reaction to this incident. During the Second World War Sandys fought with 51st (London) HAA Regiment in

3108-592: The "1912 Club" a "fanciful vision" of England in 1950 (including peace in Europe ) . In 1937, Sandys was commissioned into the 51st (London) Anti-Aircraft Brigade, Royal Artillery , of the Territorial Army (TA). In 1938, he asked questions in the House of Commons on matters of national security that reflected his TA experience. He was subsequently approached by two unidentified men, presumably representing

3219-412: The "Type IV" (of five designs), and in 1945 awarded a development and production contract to de Havilland under the designation Type 106 . The type and design were to be so advanced that de Havilland had to undertake the design and development of both the airframe and the engines. This was because in 1945 no turbojet engine manufacturer in the world was drawing-up a design specification for an engine with

3330-574: The 'headless man' whose identity was concealed during the scandalous divorce trial of Margaret Campbell, Duchess of Argyll , in 1963. Sandys died on 26 November 1987 at his home in London. He is buried in the churchyard of St Nicholas in Child Okeford , Dorset. His grave is marked by a horizontal white slab. From Sandys's first marriage, with Diana Churchill: From his second marriage, with Marie-Claire Schmitt: Among Sandys's other interests

3441-543: The 1950s, used the simpler turbojet engine; these were quickly supplanted by designs using turbofans , which are quieter and more fuel-efficient. The first airliners with turbojet propulsion were experimental conversions of the Avro Lancastrian piston-engined airliner, which were flown with several types of early jet engine, including the de Havilland Ghost and the Rolls-Royce Nene . They retained

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3552-484: The 707 remain operational, mostly as tankers or freighters . The basic configuration of the Boeing, Convair and Douglas aircraft jet airliner designs, with widely spaced podded engines underslung on pylons beneath a swept wing, proved to be the most common arrangement and was most easily compatible with the large-diameter high-bypass turbofan engines that subsequently prevailed for reasons of quietness and fuel efficiency . The Pratt & Whitney JT3 turbojets powered

3663-534: The 767 on long-distance overseas routes that did not require the capacity of larger airliners. By the late 1980s, DC-10 and L-1011 models were approaching retirement age, prompting manufacturers to develop replacement designs. McDonnell Douglas started working on the MD-11 , a stretched and upgraded successor of the DC-10. Airbus, thanks to the success of its A320 family, developed the medium-range A330 twinjet and

3774-615: The Abell Committee reported its findings. No apparent fault in the aircraft was found, and the British government decided against opening a further public inquiry into the accident. 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. Comet flights resumed on 23 March 1954. On 8 April 1954, Comet G-ALYY ("Yoke Yoke"), on charter to South African Airways ,

3885-409: The Comet 1 with more powerful engines, the Comet 2, was being developed, and orders were placed by Air India , British Commonwealth Pacific Airlines , Japan Air Lines , Linea Aeropostal Venezolana , and Panair do Brasil . American carriers Capital Airlines , National Airlines and Pan Am placed orders for the planned Comet 3, an even-larger, longer-range version for transatlantic operations. Qantas

3996-492: The Comet appeared to have achieved success for de Havilland. Popular Mechanics wrote that Britain had a lead of three to five years on the rest of the world in jetliners. As well as 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. A slightly longer version of

4107-413: The Comet's fuel tanks to be refuelled at a far greater rate than by other methods. The cockpit was significantly altered for the Comet 4's introduction, on which an improved layout focusing on the onboard navigational suite was introduced. An EKCO E160 radar unit was installed in the Comet 4's nose cone , providing search functions as well as ground and cloud-mapping capabilities, and a radar interface

4218-414: The DH 108 gained a reputation for being accident-prone and unstable, leading de Havilland and BOAC to gravitate to conventional configurations and, necessarily, designs with less technical risk. The DH 108s were later modified to test the DH.106's power controls. In September 1946, before completion of the DH 108s, BOAC requests necessitated a redesign of the DH.106 from its previous 24-seat configuration to

4329-557: The Ghosts alone were considered powerful enough and some airlines concluded that rocket motors were impractical. Sprite fittings were retained on production aircraft. Comet 1s subsequently received more powerful 5,700 lbf (25 kN) Ghost DGT3 series engines. From the Comet 2 onward, the Ghost engines were replaced by the newer and more powerful 7,000 lbf (31 kN) Rolls-Royce Avon AJ.65 engines. To achieve optimum efficiency with

4440-610: The Helsinki Olympic Games with G-ALYS on 4 August 1952. Queen Elizabeth, the Queen Mother and Princess Margaret were guests on a special flight of the Comet on 30 June 1953 hosted by Sir Geoffrey and Lady de Havilland. Flights on the Comet were about twice as fast as advanced piston-engined aircraft such as the Douglas DC-6 (490 mph (790 km/h) vs 315 mph (507 km/h), respectively), and

4551-597: The Mediterranean off the Italian island of Elba with the loss of all 35 on board. With no witnesses to the disaster and only partial radio transmissions as incomplete evidence, no obvious reason for the crash could be deduced. Engineers at de Havilland immediately recommended 60 modifications aimed at any possible design flaw, while the Abell Committee met to determine potential causes of the crash. BOAC also voluntarily grounded its Comet fleet pending investigation into

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4662-666: The Royal Navy with helping to locate and retrieve the wreckage so that the cause of the accident could be determined. 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. On 19 October 1954, the Cohen Committee was established to examine the causes of the Comet crashes. Chaired by Lord Cohen ,

4773-571: The Structures Department at the RAE, said he was not surprised by this, noting that the difference was about three to one, and previous experience with metal fatigue suggested a total range of nine to one between experiment and outcome in the field could result in failure. The RAE also reconstructed about two-thirds of G-ALYP at Farnborough and found fatigue crack growth from a rivet hole at the low-drag fibreglass forward aperture around

4884-435: The advancement of the more economical turbofan technology, which passes air around the engine core instead of through it. Jet airliners that entered service in the 1960s were powered by slim, low-bypass turbofan engines, many aircraft used the rear-engined, T-tail configuration, such as the BAC One-Eleven , Boeing 737 , and Douglas DC-9 twinjets ; Boeing 727 , Hawker Siddeley Trident , Tupolev Tu-154 trijets ; and

4995-494: The aircraft could be profitable with a load factor as low as 43 per cent, commercial success was expected. The Ghost engines allowed the Comet to fly above weather that competitors had to fly through. 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). In summer 1953, eight BOAC Comets left London each week: three to Johannesburg, two to Tokyo, two to Singapore and one to Colombo . In 1953,

5106-402: The aircraft when pulling out of a steep dive by over-manipulation of the fully powered flight controls. Investigators did not consider metal fatigue as a contributory cause. The inquiry's recommendations revolved around the enforcement of stricter speed limits during turbulence, and two significant design changes also resulted: all Comets were equipped with weather radar and the "Q feel" system

5217-439: The airframe during flight through severe weather. The Comet was withdrawn from service and extensively tested. Design and construction flaws, including improper riveting and dangerous stress concentrations around square cut-outs for the ADF (automatic direction finder) antennas were ultimately identified. As a result, the Comet was extensively redesigned, with structural reinforcements and other changes. Rival manufacturers heeded

5328-409: The armed forces of the newly independent countries of East Africa. He remained in the shadow cabinet until 1966 when he was sacked by Edward Heath . He had strongly supported Ian Smith in the dispute over Rhodesia's Unilateral Declaration of Independence . He was not offered a post when the Conservatives won the 1970 general election, but instead served as leader of the United Kingdom delegation to

5439-426: The break-up was found to have begun with a left elevator spar failure in the horizontal stabilizer . 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. Examination of the cockpit controls suggested that the pilot may have inadvertently over-stressed

5550-418: The causes of the accident. Media attention centred on potential sabotage ; other speculation ranged from clear-air turbulence to an explosion of vapour in an empty fuel tank. The Abell Committee focused on six potential aerodynamic and mechanical causes: control flutter (which had led to the loss of DH 108 prototypes), structural failure due to high loads or metal fatigue of the wing structure, failure of

5661-586: The committee tasked an investigation team led by Sir Arnold Hall , Director of the RAE at Farnborough, to perform a more-detailed investigation. Hall's team began considering fatigue as the most likely cause of both accidents and initiated further research into measurable strain on the aircraft's skin. 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 time,

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5772-779: The committee was renamed the International Committee of the Movements for European Unity and Sandys was elected its chairman and Retinger its Honorary Secretary. The Committee organised the Congress of Europe , held in The Hague from 7–11 May 1948 with 750 delegates from across Europe. Following the Congress, the International Committee was transformed into the European Movement. Sandys served as

5883-399: The control surfaces, such as the elevators, were equipped with a complex gearing system as a safeguard against accidentally over-stressing the surfaces or airframe at higher speed ranges. The Comet had a total of four hydraulic systems : two primaries, one secondary, and a final emergency system for basic functions such as lowering the undercarriage. The undercarriage could also be lowered by

5994-472: The controls was de Havilland chief test pilot John "Cats Eyes" Cunningham , a famous night-fighter pilot of the Second World War, along with co-pilot Harold "Tubby" Waters, engineers John Wilson (electrics) and Frank Reynolds (hydraulics), and flight test observer Tony Fairbrother . The prototype was registered G-ALVG just before it was publicly displayed at the 1949 Farnborough Airshow before

6105-511: The crack from propagating. 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. A further test reproduced the same results. Based on these findings, Comet 1 structural failures could be expected at anywhere from 1,000 to 9,000 cycles. Before the Elba accident, G-ALYP had made 1,290 pressurised flights, while G-ALYY had made 900 pressurised flights before crashing. Dr P. B. Walker, Head of

6216-505: The engine cells to contain debris from any serious engine failures; also, placing the engines inside the wing required a more complicated wing structure. The Comet 1 featured 5,050 lbf (22.5 kN) de Havilland Ghost 50 Mk1 turbojet engines. 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. These were tested on 30 flights, but

6327-405: The entire fuselage was tested in a dedicated water tank that was built specifically at Farnborough to accommodate its full length. In water-tank testing, engineers subjected G-ALYU to repeated repressurisation and over-pressurisation, and on 24 June 1954, after 3,057 flight cycles (1,221 actual and 1,836 simulated), G-ALYU burst open. Hall, Geoffrey de Havilland and Bishop were immediately called to

6438-456: The fuselage of the Comet; it also had the advantage of simplifying the manufacturing process. When several of the fuselage alloys were discovered to be vulnerable to weakening via metal fatigue, a detailed routine inspection process was introduced. As well as thorough visual inspections of the outer skin, mandatory structural sampling was routinely conducted by both civil and military Comet operators. The need to inspect areas not easily viewable by

6549-488: The help of advertising agencies and their strong nautical traditions of command hierarchy and chain of command (retained from their days of operating flying boats ), were quick to link the "speed of jets" with the safety and security of the "luxury of ocean liners " in the public 's perception . Aeroflot used Soviet Tupolevs , while Air France introduced French Caravelles . Commercial realities dictated exceptions, however, as few airlines could risk missing out on

6660-541: The imperfect nature of the hole created by punch-riveting could cause fatigue cracks to start developing around the rivet. Principal investigator Hall accepted the RAE's conclusion of design and construction flaws as the likely explanation for G-ALYU's structural failure after 3,060 pressurisation cycles. Jet airliner Most airliners today are powered by jet engines, because they are capable of safely operating at high speeds and generate sufficient thrust to power large-capacity aircraft. The first jetliners, introduced in

6771-460: The investigation, the Royal Navy conducted recovery operations. The first pieces of wreckage were discovered on 12 February 1954 and the search continued until September 1954, by which time 70 per cent by weight of the main structure, 80 per cent of the power section, and 50 per cent of the aircraft's systems and equipment had been recovered. The forensic reconstruction effort had just begun when

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6882-424: The jetliner flew smoothly and was highly responsive in a manner consistent with other de Havilland aircraft. Just over a year later, Rome's Ciampino airport, the site of the first Comet hull loss, was the origin of a more-disastrous Comet flight. On 10 January 1954, 20 minutes after taking off from Ciampino, the first production Comet, G-ALYP, broke up in mid-air while operating BOAC Flight 781 and crashed into

6993-412: The kerosene-filled fuel tanks, still cold from cruising at high altitude. The Comet's thin metal skin was composed of advanced new alloys and was both riveted and chemically bonded, which saved weight and reduced the risk of fatigue cracks spreading from the rivets. The chemical bonding process was accomplished using a new adhesive , Redux , which was liberally used in the construction of the wings and

7104-414: The large single-wheeled main landing gear , which was replaced on production models starting with G-ALYP by four-wheeled bogies . 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. The clean, low-drag design of the aircraft featured many design elements that were fairly uncommon at

7215-597: The last Comet 4, used as a research platform, made its final flight in 1997. The most extensive modification resulted in a specialised maritime patrol derivative, the Hawker Siddeley Nimrod , which remained in service with the Royal Air Force until 2011, over 60 years after the Comet's first flight. On 11 March 1943, the Cabinet of the United Kingdom formed the Brabazon Committee , which

7326-461: The latest widebody airliners are the Airbus A380 (first flight in 2005), Boeing 787 (first flight in 2009) and Airbus A350 (first flight in 2013). These improvements allowed longer ranges and lower cost of transportation per passenger. Sukhoi Superjet 100 and Airbus A220 (formerly Bombardier CSeries) are examples of narrowbodies with similar level of technological advancements. The A380

7437-415: The lessons learned from the Comet when developing their own aircraft. Although sales never fully recovered, the improved Comet 2 and the prototype Comet 3 culminated in the redesigned Comet 4 series which debuted in 1958 and remained in commercial service until 1981. The Comet was also adapted for a variety of military roles such as VIP, medical and passenger transport, as well as surveillance;

7548-470: The naked eye led to the introduction of widespread radiography examination in aviation; this also had the advantage of detecting cracks and flaws too small to be seen otherwise. Operationally, the design of the cargo holds led to considerable difficulty for the ground crew, especially baggage handlers at the airports. The cargo hold had its doors located directly underneath the aircraft, so each item of baggage or cargo had to be loaded vertically upward from

7659-518: The new powerplants, the air intakes were enlarged to increase mass air flow. Upgraded Avon engines were introduced on the Comet 3, and the Avon-powered Comet 4 was highly praised for its takeoff performance from high-altitude locations such as Mexico City where it was operated by Mexicana de Aviacion , a major scheduled passenger air carrier. The earliest production aircraft, registered G-ALYP ("Yoke Peter"), first flew on 9 January 1951 and

7770-406: The nickname "Jumbo Jet". The Boeing 747 revolutionized air travel by making commercial air travel more affordable as ticket prices fell and airlines improved their pricing practices. Other wide-body designs included the McDonnell Douglas DC-10 and Lockheed L-1011 TriStar trijets , smaller than the Boeing 747 but capable of flying similar long-range routes from airports with shorter runways. There

7881-480: The normal service ceiling of 36,000 ft (11,000 m). One window frame survived 100 psi (690 kPa), about 1,250 per cent over the maximum pressure it was expected to encounter in service. 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. The prototype's maiden flight, out of Hatfield Aerodrome, took place on 27 July 1949 and lasted 31 minutes. At

7992-463: The order total was revised to 10. 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. On whether we grasp this opportunity and so establish firmly an industry of the utmost strategic and economic importance, our future as a great nation may depend. Duncan Sandys , Minister of Supply, 1952. A design team

8103-528: The original Boeing 707 and DC-8 models; in the early 1960s the JT3 was modified into the JT3D low-bypass turbofan for long-range 707 and DC-8 variants. The de Havilland and Tupolev designs had engines incorporated within the wings next to the fuselage , a concept that endured only within military designs while the Caravelle pioneered engines mounted either side of the rear fuselage. The 1960s jet airliners include

8214-499: The paired multi-engined Ilyushin Il-62 , and Vickers VC10 . The rear-engined T-tail arrangement is still used for jetliners with a maximum takeoff weight of less than 50 tons. As of April 2023, 15,591 Boeing 737s have been ordered and 11,395 delivered, and it remains the most produced jet aircraft. Other 1960s developments, such as rocket-assisted takeoff ( RATO ), water-injection , and afterburners (also known as reheat) used on supersonic jetliners (SSTs) such as Concorde and

8325-486: The period. Amenities included a galley that could serve hot and cold food and drinks, a bar , and separate men's and women's toilets. Provisions for emergency situations included several life rafts stored in the wings near the engines, and individual life vests were stowed under each seat. One of the most striking aspects of Comet travel was the quiet, "vibration-free flying" as touted by BOAC. For passengers used to propeller-driven airliners, smooth and quiet jet flight

8436-473: The powered flight controls, failure of the window panels leading to explosive decompression, or fire and other engine problems. The committee concluded that fire was the most likely cause of the problem, and changes were made to the aircraft to protect the engines and wings from damage that might lead to another fire. The cost of solving the Comet mystery must be reckoned neither in money nor in manpower. Prime Minister Winston Churchill , 1954. During

8547-512: The program after realizing it would never recoup the €25 billon ($ 30 billion) spent on research and development . In all, 251 A380s were produced for and flown by 14 airlines. As of June 2023, Boeing has produced 1,054 787s for 34 airlines and has 592 unfulfilled orders. Duncan Sandys Duncan Edwin Duncan-Sandys, Baron Duncan-Sandys CH , PC ( / s æ n d z / ; 24 January 1908 – 26 November 1987),

8658-633: The rationalisation (merger) of much of the British military aircraft and engine industry. Sandys continued as a minister at the Commonwealth Relations Office , later combining it with the Colonies Office, until the Conservative government lost power in 1964. In this role he was responsible for granting several colonies their independence and was involved in managing the British response to several conflicts involving

8769-487: The related long-range A340 quad-jet. In 1988, Boeing began developing what would be the 777 twinjet, using the twin-engine configuration given past design successes, projected engine developments, and reduced-cost benefits. In addition, Boeing also released a major update on their 747, the 747-400 . The most modern airliners are characterized by increased use of composite materials, high-bypass ratio turbofan engines, and more advanced digital flight systems. Examples of

8880-513: The remainder of the coalition and in the Churchill Caretaker Ministry . While a minister he was chairman of a War Cabinet Committee for defence against German flying bombs and rockets , on which he frequently clashed with the scientist and intelligence expert R. V. Jones . However, he lost his seat in the 1945 general election . He resigned his TA commission as a lieutenant-colonel the following year. Sandys played

8991-406: The same conditions. As a result, de Havilland re-profiled the wings' leading edge with a pronounced "droop", and wing fences were added to control spanwise flow. A fictionalised investigation into the Comet's takeoff accidents was the subject of the novel Cone of Silence (1959) by Arthur David Beaty , a former BOAC captain. Cone of Silence was made into a film in 1960, and Beaty also recounted

9102-573: 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 cut out. The failure then occurred longitudinally along a fuselage stringer at the widest point of the fuselage and through a cut out for an escape hatch. The skin thickness was discovered to be insufficient to distribute the load across the structure, leading to overloading of fuselage frames adjacent to fuselage cut outs. (Cohen Inquiry accident report Fig 7). The fuselage frames did not have sufficient strength to prevent

9213-652: The start of flight trials. A year later, the second prototype G-5-2 made its maiden flight. The second prototype was registered G-ALZK in July 1950 and it was used by the BOAC Comet Unit at Hurn from April 1951 to carry out 500 flying hours of crew training and route-proving. Australian airline Qantas also sent its own technical experts to observe the performance of the prototypes, seeking to quell internal uncertainty about its prospective Comet purchase. Both prototypes could be externally distinguished from later Comets by

9324-491: The story of the Comet's takeoff accidents in a chapter of his non-fiction work, Strange Encounters: Mysteries of the Air (1984). The Comet's second fatal accident occurred on 2 May 1953, when BOAC Flight 783 , a Comet 1, registered G-ALYV, crashed in a severe thundersquall six minutes after taking off from Calcutta-Dum Dum (now Netaji Subhash Chandra Bose International Airport ), India, killing all 43 on board. Witnesses observed

9435-503: The stresses involved, were both located along the failure crack. Once the crack initiated the skin failed from the point of the ADF cut out and propagated downward and rearward along a stringer resulting in an explosive decompression. It was also found that the punch-rivet construction technique employed in the Comet's design had exacerbated its structural fatigue problems; the aircraft's windows had been engineered to be glued and riveted, but had been punch-riveted only. Unlike drill riveting,

9546-417: The then widely held view that jet engines were too fuel-hungry and unreliable for such a role. As a result, committee member Sir Geoffrey de Havilland , head of the de Havilland company, used his personal influence and his company's expertise to champion the development of a jet-propelled aircraft; proposing a specification for a pure turbojet -powered design. The committee accepted the proposal, calling it

9657-458: The thrust and specific fuel consumption that could power an aircraft at the proposed cruising altitude (40,000 ft (12,000 m)), speed, and transatlantic range as was called for by the Type 106. First-phase development of the DH.106 focused on short- and intermediate-range mailplanes with small passenger compartments and as few as six seats, before being redefined as a long-range airliner with

9768-416: The time, including a swept-wing leading edge, integral wing fuel tanks, and four-wheel bogie main undercarriage units designed by de Havilland. Two pairs of turbojet engines (on the Comet 1s, Halford H.2 Ghosts, subsequently known as de Havilland Ghost 50 Mk1s) were buried in the wings. The original Comet was the approximate length of, but not as wide as, the later Boeing 737-100 , and carried fewer people in

9879-439: The top of the baggage truck, then slid along the hold floor to be stacked inside. The individual pieces of luggage and cargo also had to be retrieved in a similarly slow manner at the arriving airport. The Comet was powered by two pairs of turbojet engines buried in the wings close to the fuselage. Chief designer Bishop chose the Comet's embedded-engine configuration because it avoided the drag of podded engines and allowed for

9990-567: The two inboard piston engines, the jets being housed in the outboard nacelles. The first airliner with jet power only was the Nene-powered Vickers VC.1 Viking G-AJPH , which first flew on 6 April 1948. The early jet airliners had much lower interior levels of noise and vibration than contemporary piston-engined aircraft, so much so that in 1947, after piloting a jet powered aircraft for the first time, Wing Commander Maurice A. Smith, editor of Flight magazine, said, "Piloting

10101-463: The wing roots; Halford H.2 Ghost engines were eventually applied as an interim solution while the Avons cleared certification. The redesigned aircraft was named the DH.106 Comet in December 1947. Revised first orders from BOAC and British South American Airways totalled 14 aircraft, with delivery projected for 1952. As the Comet represented a new category of passenger aircraft, more rigorous testing

10212-468: The wingless Comet on fire plunging into the village of Jagalgori, leading investigators to suspect structural failure. After the loss of G-ALYV, the Government of India convened a court of inquiry to examine the cause of the accident. Professor Natesan Srinivasan joined the inquiry as the main technical expert. A large portion of the aircraft was recovered and reassembled at Farnborough, during which

10323-806: Was historic architecture . He formed the Civic Trust in 1957 and was its president; the Royal Institution of British Architects made him an honorary Fellow in 1968, and the Royal Town Planning Institute made him an honorary member. He was also a trustee of the World Security Trust. Between 1969 and 1984 he was President of Europa Nostra and acted for the preservation of the European cultural and architectural heritage. His business activities included

10434-580: Was 12 years old. His mother married Frederick Hamilton Lister in October that year, becoming Mildred Helen Lister. He was educated at Eton College and Magdalen College, Oxford . Sandys entered the diplomatic service in 1930, serving at the Foreign Office in London as well as at the embassy in Berlin . He became Conservative Party Member of Parliament (MP) for Norwood in south London in

10545-523: Was a British politician and minister in successive Conservative governments in the 1950s and 1960s. He was a son-in-law of Winston Churchill and played a key role in promoting European unity after World War II . Sandys, born on 24 January 1908 at the Manor House, Sandford Orcas , Dorset, was the son of George John Sandys , a Conservative Member of Parliament (1910–1918), and Mildred Helen Cameron. Sandys's parents divorced in January 1921 when he

10656-524: Was a development priority. 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. Sections of pressurised fuselage were subjected to high-altitude flight conditions via a large decompression chamber on-site and tested to failure. Tracing fuselage failure points proved difficult with this method, and de Havilland ultimately switched to conducting structural tests with

10767-539: Was a novel experience. For ease of training and fleet conversion, de Havilland designed the Comet's flight deck layout with a degree of similarity to the Lockheed Constellation , an aircraft that was popular at the time with key customers such as BOAC. The cockpit included full dual-controls for the captain and first officer, and a flight engineer controlled several key systems, including fuel, air conditioning and electrical systems. The navigator occupied

10878-492: Was a write-off. 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 . The aircraft plunged into a dry drainage canal and collided with an embankment, killing all five crew and six passengers on board. The accident was the first fatal jetliner crash. In response, Canadian Pacific cancelled its remaining order for

10989-716: Was also the market debut of the European consortium Airbus , whose first aircraft was the twinjet Airbus A300 . In 1978, Boeing unveiled the twin-engine Boeing 757 to replace its 727 , and the wide body twin-engine 767 to challenge the Airbus A300 . The mid-size 757 and 767 launched to market success, due in part to 1980s extended-range twin-engine operational performance standards ( ETOPS ) regulations governing transoceanic twinjet operations. These regulations allowed twin-engine airliners to make ocean crossings at up to three hours' distance from emergency diversionary airports . Under ETOPS rules, airlines began operating

11100-459: Was built into the Comet 4 cockpit along with redesigned instruments. Sud-Est 's design bureau, while working on the Sud Aviation Caravelle in 1953, licensed several design features from de Havilland, building on previous collaborations on earlier licensed designs, including the DH 100 Vampire ; the nose and cockpit layout of the Comet 1 was grafted onto the Caravelle. In 1969, when the Comet 4's design

11211-399: Was commercially promising at its debut in 1952. Within a year of the airliner's entry into service, three Comets were lost in highly publicized accidents after suffering catastrophic mishaps mid-flight. Two of these were found to be caused by structural failure resulting from metal fatigue in the airframe , a phenomenon not fully understood at the time; the other was due to overstressing of

11322-622: Was created Baron Duncan-Sandys , of the City of Westminster , on 2 May 1974. He was an active early member of the Conservative Monday Club . In 1935, Sandys married Diana Churchill , daughter of the future prime minister Winston Churchill . They divorced in 1960. In 1962, he married Marie-Claire ( née Schmitt), who had been previously married to Robert Hudson, 2nd Viscount Hudson . The marriage lasted until Sandys's death. It has long been speculated that he may have been

11433-542: Was discontinued in 2019 and the last plane was delivered to Emirates in 2021. Airbus began designing it in the 90s with the expectation that airlines would be moving many people between large hubs with just one flight. Their focus was on building a very large plane with a conventional metal airframe and engines to supersede the Boeing 747 . However, airlines started to operate more direct, point-to-point flights between smaller cities which made twin engine jets more attractive and economical to operate. For comparison, Boeing took

11544-577: Was formed in 1946 under the leadership of chief designer Ronald Bishop , who had been responsible for the Mosquito fighter-bomber. Several unorthodox configurations were considered, ranging from canard to tailless designs; All were rejected. The Ministry of Supply was interested in the most radical of the proposed designs, and ordered two experimental tailless DH 108s to serve as proof of concept aircraft for testing swept-wing configurations in both low-speed and high-speed flight. During flight tests,

11655-411: 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. On 26 October 1952, the Comet suffered its first hull loss when a BOAC flight departing Rome's Ciampino airport failed to become airborne and ran into rough ground at the end of the runway. Two passengers sustained minor injuries, but the aircraft, G-ALYZ,

11766-463: Was introduced, which ensured that control column forces (invariably called stick forces) would be proportional to control loads. This artificial feel was the first of its kind to be introduced in any aircraft. The Comet 1 and 1A had been criticised for a lack of " feel " in their controls, and investigators suggested that this might have contributed to the pilot's alleged over-stressing of the aircraft; Comet chief test pilot John Cunningham contended that

11877-632: Was knowledgeable on army matters. Robotham of Rolls-Royce who had headed development of the Meteor tank engine in WWII was surprised and pleased when in 1963 Sandys said "I regard the adoption of the Meteor tank engine as the absolute turning-point in the history of British tank development", at the opening of a Rolls-Royce aero engine factory at East Kilbride (aero engines being Rolls-Royce's main business). From 1944 to 1945 he served as Minister of Works for

11988-817: Was modified by Hawker Siddeley to become the basis for the Nimrod, the cockpit layout was completely redesigned and bore little resemblance to its predecessors except for the control yoke. Diverse geographic destinations and cabin pressurisation alike on the Comet demanded the use of a high proportion of alloys, plastics, and other materials new to civil aviation across the aircraft to meet certification requirements. The Comet's high cabin pressure and high operating speeds were unprecedented in commercial aviation, making its fuselage design an experimental process. 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

12099-486: Was on a leg from Rome to Cairo (of a longer route, SA Flight 201 from London to Johannesburg), when it crashed in the Mediterranean near Naples with the loss of all 21 passengers and crew on board. The Comet fleet was immediately grounded once again and a large investigation board was formed under the direction of the Royal Aircraft Establishment (RAE). Prime Minister Winston Churchill tasked

12210-706: Was subsequently lent to BOAC for development flying by its Comet Unit. 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. On 2 May 1952, as part of BOAC's route-proving trials, G-ALYP took off on the world's first jetliner flight with fare-paying passengers and inaugurated scheduled service from London to Johannesburg . The final Comet from BOAC's initial order, registered G-ALYZ, began flying in September 1952 and carried cargo along South American routes while simulating passenger schedules. Prince Philip returned from

12321-499: Was tasked with determining the UK's airliner needs after the conclusion of the Second World War . One of its recommendations was for the development and production of a pressurised, transatlantic mailplane that could carry 1 long ton (2,200 lb; 1,000 kg) of payload at a cruising speed of 400 mph (640 km/h) non-stop. Aviation company de Havilland was interested in this requirement, but chose to challenge

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