Comet 4C (nose section) of the North East Aircraft Museum, Britain

Unfortunately, the North East Aircraft Museum only possesses the nose section. The Comet was the world's first passenger jet aircraft to enter airline service, on 2. May 1952, but it soon experienced several crashes, resulting in the aircraft being grounded.

The traditional story surrounding the Comet is that it was 'ahead of its time' and therefore it was unlucky in suffering from the 'unknown' problem of metal fatigue.

The truth of the matter is that the British Government and BOAC gave the go-ahead to an aircraft which they knew had not been tested properly, and even when crashes started occuring, it took five incidents before the aircraft was grounded indefinitely.

It was only then that the testing which should have been done beforehand was carried out. This resulted in a report of February 1955, revealing severe problems with metal fatigue.

Beginnings

     

Initial planning for the post-war era of jet aircraft can be traced as far back as 1941.

In 1946, the contract for the design of a jet airliner was awarded to De Havilland, with a finishing deadline of 1952, which was an almost impossible deadline. It turned out that project was to require 3 years from its final inception until its maiden flight, whereas previous aircraft tended to require 7 years.

Nevertheless, 8 Comets had already been sold before they were even built.

The design was placed under the leadership of Ronald Bishop.

A decision was made to set up the production line before the prototype had flown. This involved a huge financial risk - there would be great financial problems if they had to change the design.

The Comet first flew on 27. July 1949, flown by John Cunningham. It was the star attraction at the 1949 Farnborough Air Show but during its flight at the show, a panel buckled, showing that the skin was too thin.

A basic problem here was that De Havilland insisted on using their own Ghost engine, whereas BOAC had wanted the more powerful Rolls-Royce Avon. Using the less-powerful Ghost meant reducing the weight. This need to reduce weight even meant that the early aircraft were not painted.

The RAE (Royal Aircraft Establishment) at Farnborough had already found problems with fatigue. Bishop was asked to test for fatigue, but he was apparently relectant to do so. RAE also informed BOAC, but they did not want to delay for tests either.

By November 1951, the Ministry of Supply threatened to stop the project because of continuing concerns over fatigue, BOAC becoming anxious as well. Nevertheless an amazing decision was taken that full-scale testing would be carried out but the aircraft would still go into service as planned (in reality, this full-scale testing was not actually carried out until the Comet fleet had been grounded, a few years later).

It flew commercially (with BOAC) for the first time on 2. May 1952, flying to Johannesburg.

Prior to the introduction of the Comet, the most successful airliner was the Lockheed Constellation which flew at a speed of 400 km/hr at less than 9000 meters. The Comet flew at 800 km/hr., and flew higher above the worst weather, and more efficiently - at height the engines produce less power but there is less drag on the aircraft, therefore fuel consumption above 9000 metres is less than below. Further it had none of the vibration associated with piston-engined aircraft.

In the first year of service, 28.000 passengers were carried, and it was ordered by Canadian Pacific, Air France and the Canadian Air Force. Over 50 aircraft were ordered. (The arrival of the Boeing 707 was still three years into the future)

Before the first year was out, work started on the Comet 2 (with Avon engines). Orders were received from British Commonwealth Pacific Airlines, Japan Airlines and from Brazil. Production was considered to be too large for the main factory alone and a duplicate line was established at Shorts in Belfast.

In Autumn 1952, the Comet 3 was announced, capable of carrying 76 passengers, and at the end of the year, Pan Am ordered three of these planned Comet 3s.

Competition from the Boeing 707

     

The Comet is held by some sources to be direct inspiration for the Boeing 707, at least in part anyway. Representatives from Boeing had a chance to see the aircraft at the Farnborough Air Show in 1950, and at that time and in the early 50s, Boeing was the only American manufacturer with experience of large jet aircraft, with the B47.

Boeing poured $15 million into the Boeing 707 project, a quarter of Boeing's net worth (incidentally, the design was simply the 707th. to come from the design office). They did consider the 44 passengers of the Comet to be too small and aimed to double the number. They also disliked the idea of the engines being hidden in the wing, close to the fuselage - an engine failure was considered to be potentially disastrous. Instead the engines were contained in pods below the wing, away from the fuselage.

The 707 first flew on 15. July 1954, it was 39 meters long and weighed 72.575 kg . The Pratt and Whitney engine was three times as powerful as the Ghost engine used in the first Comets. Another difference, especially important in view of subsequent events, was that the fuselage wall was four and a half times as thick, and additionally was strengthened, at intervals, with titanium strips.

Disaster Strikes

     

Incident No. 1

A Comet taking off from Rome overshot the runway. No-one was hurt and an investigation blamed the pilot. The pilot, Foote, was forced to sign a confession that it was his fault, and he was moved to the freighter division. In reality, De Havilland knew there could be problems with the plane's take-off performance - they were relying on the experience of pilots to over-ride this deficit.

Incident No. 2

Crash-on take-off, with 11 people killed. De Havilland had no choice but to re-design the wing. Nevertheless, Foote was never re-instated to the Comet fleet.

This aircraft was being delivered to Canadian Pacific. But instead of going the simple way across the Atlantic, Canadian Pacific attempted to display it as a record-setter - it was to go the other way, and in so doing establish a new elapsed-time air record from Britain to Australia.

The aircraft CF-CUN, named "Empress of Hawaii", did not become airborne on takeoff from Karachi and crashed into the dry bed of a river. CF-CUN was the first passenger jetliner involved in a fatal accident. Canadian Pacific canceled their order for two more aircraft.

Incident No. 3

On 2. May 1953, on the first anniversary of the introduction of the Comet into BOAC service, a Comet crashed after leaving Calcutta. The accident investigators blamed it on bad weather.

Incident No. 4

On 10. January 1954, Comet G-ALYP, which had logged 3600 hours, crashed into the sea after taking off from Rome. The difficulties arose at the top of its climb, at about 10.500 meters - the pilot had been talking to a colleague on another aircaft and transmission had cut off instantaneously. The Comets were grounded but only for a short period - 10 weeks after the crash, flights resumed. This was before an investigation had taken place - they were still fishing the evidence out of the Mediterreanean.

At a meeting of the 140 Comet crew, an agreement to return to work was passed by just one vote.

Incident No. 5

Two weeks after flying resumed, on 3. April 1954 another Comet, G-ALYY of South African Airways (on charter from BOAC), was lost, again after leaving Rome, and again the difficulties arose at the same height. Every Comet was grounded indefinitely.

It was only now that testing was carried out at Farnborough. The immediate evidence from the wreckage was that the aircaft had suffered catastrophic explosion of the fuselage. The tests showed that the Comets had suffered catastrophic metal fatigue (equivalent to the effect of a 250kg bomb). Initially Farnborough had been primarily worried about the wings, but it was now learnt about the fuselage as well. The thin nature of the aircraft's skin had not been helped by rivets around the windows, forming the source of cracks. The square windows themselves were of the wrong shape (the Americans had already been very dubious about this shape of window), and De Havilland had decided to rivet them in, after experiencing great difficulties with their original methods. Also, de Havilland had failed to take full notice of the short period within which pressures change, as the Comet climbs or descends.

All of Farnborough's findings became fully available to all aircraft manufacturers.

Again amazingly, an inquiry at the time absolved De Havilland, BOAC and the British Government of any blame, saying that the effects of fatigue were unknown. No compensation was given for loss of life.

As detailed below, the Comet did rise again as the Comet 4, but only 79 were built. The original Comet had expected over 1,000 sales.

Within 5 years, De Havilland was taken over..

Comet 4

     

The Comet arose from these disasters as the Comet 4, although by then its initial lead had suffered a considerable setback, and they had competition not just from the Boeing 707 but also from the Douglas DC8. It did however enter transatlantic service 22 days before the Boeing 707, and was capable of carrying twice as many passengers as the early Comets.

The discontinued Comet 3 was used as a testbed for the Comet 4, and BOAC ordered the type in 1955. These were introduced into BOAC in 1958. Only one American company ordered the type - Capitol Airways, but that order was cancelled when Capitol was taken over by United Airways.

113 were built.They also served with Mexicana, Eygpt Airlines, Aerolinas Argentina, Malaysian Airlines and Singapore Airlines. It flew with Dan Air of Britain until 1980.

The 4C was the most successful of the Comet 4 types, and the last two 4C aircraft were used for development of the Nimrod.

Apart from its civil use, it also went into Transport Command, RAF as the first jet military transport. It served in this role until 1975, when it was replaced by the VC10.

Comet production ended in 1962.

De Havilland Comet

Variants

     

  • Prototype as above.

  • Mk 1 first flew 9. Jan. 1951. MTOW (Maximum Take-Off Weight) 47.600kg. 9 built (5 crashed).

  • Mk 1A First customer Canadian Pacific. MTOW - 49895 kg . 10 built (3 crashed)

  • Mk 1B MTOW - 53.070 kg . Had oval windows. Four Mk 1A were upgraded to this standard.

  • Mk 2X Mark 2 prototype with Avon engines.

  • Mk 2 MTOW - 54430 kg . First flew on 27. August 1953. Crashes stopped production, but some were upgraded.

  • Mk C2 used by RAF. Reinforced and had oval windows.

  • Mk 3 First flew 19. July 1954. Due to crashes, Mk 3 program was abandoned. Although the Mark 3 was used as a testbed for the Mark 4. In this guise a Comet 3 circled the Earth in 1955. From Hatfield, it went to Australia, New Zealand, Fiji, Hawaii, Vancouver, Montreal and then London non-stop. This was the first round-the-world trip by a commercial jet aircraft and the first jet journey across the Pacific.

  • Mk 4 different alloy used for the fuselage. First flew 27. April 1958. Entered service with BOAC in October 1958. MTOW - 73480 kg . First London - NY service. 28 built

  • Mk 4A shorter range version of Comet 4. Ordered by Capitol Airways.

  • Mk 4B shorter span version

  • Mk 4C combination of the fuselage of the 4B and the wings of the Mk 4.. First flew on 31. October 1959. Delivered on 14. January 1960. MTOW identical to Mk. 4. 23 built

  • Mk 5 Project never brought to fruition.

De Havilland Comet

Nimrod

     

The Comet 4C was developed into a military aircraft - the Nimrod maritime patrol aircraft, which entered RAF service in 1969. This had a shorter fuselage with an extended "double-bubble" cross-section, the lower bay being a weapons and equipment accommodation bay.

The Nimrod has Spey turbofans instead of Avons, and can cruise with two of these engines switched off.

49 were built plus two rebuilds from Comet 4Cs. Further-upgraded Nimrods are due to enter service in 2005.

Links

     

Other Comet pages on the Internet