The Dawn of the Jet-age

Sir Geoffrey de Havilland celebrated his 67th birthday on July 27, 1949. At the twilight of a career that had spanned two World Wars, he had, literally, seen the entire history of manned flight. From the days when he designed, built, and taught himself to fly his own aircraft in 1909, Sir Geoffrey had gone on to found his own company and build over 80 aircraft types, both civil and military. The man was a true pioneer.

On this occasion, the design team led by engineer Ron Bishop and chief test pilot John Cunningham (who shared his boss’s birthday) had a special treat for him: the first test flight of the D.H.106 prototype, the world’s first jet-powered airliner, was scheduled for this day. The sleek machine — with its four Frank Halford-designed de Havilland Ghost engines buried in the wings — performed beautifully. Sir Geoffrey was convinced he had a winner that would revolutionize air transport and named it ‘Comet’, in a nod to the D.H.88 Comet, the sleek, twin-engine, purpose-built racing monoplane which had famously won the London to Melbourne air race in 1934, thus cementing the company’s place in aviation history.

Development

The Brabazon Committee, spurred on by Sir Geoffrey, had made funding available for this new commercial project. Now de Havilland Aircraft, and Britain, was about to leap ahead of the entire aviation world with its new jet-propelled passenger transport.

Across the ‘pond’, US manufacturers were uninterested in developing anything that radical. The great piston-engine prop-liners such as the Lockheed 749 and 1049 Constellations and Douglas DC-6 roared their way across the skies, and both their manufacturers were content to develop variants of those dominant types. The United States Air Force (USAF) wanted a fast jet-bomber, and Boeing had just demonstrated a prototype in 1947; but development issues would delay the B-47 Stratojet’s entry into service until 1951. Meanwhile there was no talk of a jet-powered civil airliner in the USA, and Canadian attempts to build one met with little support.

That meant Britain had a working prototype and wide-open skies in which to fly it. So the de Havilland team worked tirelessly to refine their design. With a starting order for 14 Comets from state-owned BOAC (British Overseas Airways Corporation) and two for the Air Ministry, they were all set to go.

The challenges of designing such a revolutionary type were legion. The flight controls of the revolutionary new aircraft were to be hydraulically powered — a ‘first’ on the Comet, which has since become standard. The Comet was designed to fly at altitudes up to 40,000 feet — high into the stratosphere and above the weather. But temperatures at these altitudes were as low as minus 70°C. The cabin had to be pressurized to an unprecedented level. Accordingly, de Havilland’s engineers pioneered the use of ‘bleed air’ from the turbine engines to heat and pressurize the cabin.

The dangers of a pressurization failure were recognized early in the design and testing phases. The aircraft cabin was designed “like a submarine”, in the words of an engineer on the project. The team built a water tank large enough to submerge a full-scale fuselage, and subjected it to a series of tests designed to rule out the possibility of structural failure. The cabin was designed to a safety factor of 2.5 times the pressure it would undergo in line service.

Operational success

The second prototype of the Comet flew in late 1950, and the first production version, registered G-ALYP, in January 1951. BOAC operated the world’s first jet-powered passenger flight from London to Johannesburg, South Africa on May 2, 1952, and it was an instant success. Leaving London-Heathrow at 3pm, it reached Johannesburg in less than 24 hours, despite stops in Rome, Beirut, Khartoum (Sudan), Entebbe (Uganda), and Livingstone (Zambia; then in Northern Rhodesia/Zimbabwe).

By contrast a BOAC Lockheed 049 Constellation would take an additional seven hours to do the same trip. The Comet, climbing to a cruise altitude of 40,000ft, was quiet, smooth, and could fly above the weather. In one stroke, all the great propeller airliners of the world were rendered obsolete.

The British press was jubilant. The Comet’s second destination was Colombo, Ceylon (now Sri Lanka) via Rome, Beirut, Bahrain, Karachi and Bombay (Mumbai). By the summer of 1953, eight BOAC Comets left London each week on scheduled services: three to Johannesburg, two to Tokyo, two to Singapore and one terminating in Colombo.

With no other jet-powered airliner in development (the Avro Canada C102 had been cancelled) the world’s leading airlines raced to place orders for the Comet and its variants. Air France and its rival Union Aéromaritime de Transport (UAT; later to become UTA) bought Comet 1As. Air-India and Japan Air Lines placed orders, as did Canadian Pacific Air Lines and British Commonwealth Pacific Airlines (BCPA, based in Sydney, Australia, later taken over by Qantas). In the USA, Pan Am, Capital Airlines and National Airlines placed orders for the Comet 3, a longer-range version designed for trans-Atlantic routes. Airlines in Brazil and Venezuela joined the queue. Britain’s aviation industry had gained a stranglehold on the future — or so it seemed.

Disaster strikes early

But then a series of accidents and incidents began. On October 26, 1952 a BOAC aircraft, registered G-ALYZ, on the Johannesburg service, ran off the runway on takeoff from Rome. Fortunately, there were only minor injuries to some of the 35 passengers and eight crew members, but the aircraft was destroyed. The cause was attributed to “an error of judgement by the captain in not appreciating the excessive nose-up attitude of the aircraft during the takeoff.” The lack of ‘feel’ due to the powered controls was identified as a contributing causal factor.

The second Comet accident occurred on March 3, 1953 at the Karachi-Mauripur airbase of Britain’s Royal Air Force (RAF) in Pakistan, during the delivery flight to Australia of Canadian Pacific Air Lines’ (CPAL) first Comet 1A, registered CF-CUN and named Empress of Hawaii. The airline was to launch its jet service to Canada via Honolulu from Sydney, and the brand-new airplane was being positioned to Australia. The pilots had never conducted a night takeoff before, especially at close to the airplane’s maximum weight.

The Comet failed to become airborne, in similar circumstances to those which caused the pilot of the BOAC Comet at Rome to rotate, or raise the nose, early during takeoff. As such, the aircraft, which had yet to gain sufficient airspeed for takeoff, ran off the runway and was totally destroyed.

This was the world’s first fatal jet accident, with all five crew members and six passengers losing their lives. The cause of the early and rapid rotation was later discovered to be a combination of the powered controls added to the Comet’s slender wings. After the accident CPAL cancelled its remaining orders for a second Comet 1A and, subsequently, three examples of the Comet 2.

The first fatal Comet accident in line service was to BOAC’s Flight 783, soon after take-off from Dum Dum Airport, Calcutta (now Kolkata), India on May 2, 1953. The aircraft, registered G-ALYV, appeared to break apart in mid-air, and the subsequent inquiry found the probable cause to be “Structural failure of the airframe during flight through a thunder squall.” Today it would probably be attributed to an encounter with a particularly severe thunderstorm cell known as a ‘microburst’; but such phenomena were not well understood at the time.

Despite these highly publicized accidents, BOAC and other customers continued to operate the Comet. However, not long after the May 1953 crash of BOAC’s Comet 1 at Calcutta, in June and July of the same year two more Comets were destroyed in non-fatal accidents: on June 25, a UAT Comet 1A, F-BGSC, on landing at Dakar, Senegal; and on July 25, another BOAC Comet 1, G-ALYR, while taxiing, again at Calcutta.

But worse was to come. On January 10, 1954 the first production Comet 1, BOAC’s G-ALYP, crashed into the Mediterranean Sea a few minutes after takeoff from Rome-Ciampino on a scheduled flight to London. BOAC voluntarily grounded its Comet fleet pending an investigation into this latest tragedy.

Initial conclusions

A media frenzy ensued, with speculations of sabotage or an onboard explosion. With no witnesses to the accident and no radio transmissions by the crew, recovery of the wreckage for analysis was imperative. The Royal Navy undertook to recover the remains, and the first pieces were dredged up within a month. Further exploration until September 1954 led to 70% of the structure being retrieved from the ocean bed. A panel of enquiry led by Charles Abell, Deputy Operations Director (Engineering) of BOAC, was duly convened to investigate the latest tragedy to Britain’s most prestigious product.

The panel found no fault with the aircraft. Despite intense commercial and media pressure, the British government decided against instituting a public enquiry into the accident, and Comet flights were permitted to resume in March 1954.

Another tragedy

But only a few weeks after the loss of G-ALYP, on April 8, 1954, another BOAC Comet 1, G-ALYY, en route from London to Johannesburg and operating on behalf of South African Airways, crashed off the coast of Naples, Italy. This time a public enquiry and investigation board under the auspices of the Royal Aircraft Establishment was tasked with finding the cause. The Comet’s Certificate of Airworthiness was revoked, BOAC grounded its entire fleet, and de Havilland halted production of its showpiece Comet jetliner.

The crown jewel of British industry was in jeopardy.

End of Part 1 — part 2 is here

This is part of a series on the propliners of the 1950s and the slow transition to the jet age. It all began with the DC-3 of course, and my columns move through the other Douglas propliners, the Boeing 377, Lockheed’s Electras and the elegant Constellation. The Brabazon Committee which sparked such a wave of innovation in the UK with the Vickers Viscount, the Bristol Britannia and the ill-fated de Havilland Comet. Many other significant aircraft, such as Avro Canada’s innovative but aborted C-102 passenger jet and the Sud-Aviation Caravelle, which led us into the start of the Jet Age have columns too.

A few quirky segues I couldn’t resist: the ‘Double Sunrise’ flights between my two homelands Ceylon and Australia; the wonderful Carvairs and that very British habit of taking your car on holiday. I also had to write a paean to my beloved A380 and all my pilot friends in the Gulf as COVID ended that little dream.

Thanks for reading and I hope you enjoyed the series as much as I have relished writing them. My special thanks to my old friend, mentor, editor and repository of knowledge Roger Thiedeman, for all the encouragement and support throughout this project.

I love airplanes. As an airline captain I flew many including the A380 and Boeing 777. But wish I’d had the opportunity to fly some of these old propliners.