De Havilland DH106 Comet 1 (GALVG)
De Havilland DH106 Comet 1 (GALVG)
The De Havilland Aircraft Company DH106 Comet was the World’s first pressurised commercial jet airliner and it was the source of enormous national pride. Its introduction into BOAC service in May 1952, was greeted as the dawning of a new age in passenger travel.
Comet Production
Prototype Comet 1 Assembly Shop
The first DH106 Comet 1 prototype (G-5-1 / G-ALVG) flew at Hatfield for the first time on 27th July 1949, and it was immediately apparent that the type would set new standards for both flight performance and passenger comfort.  
The flight also took place on Sir Geoffrey de Havilland's 67th birthday, an occasion he shared with Chief Test Pilot John Cunningham, who was just 33-years old on the same day.
The first prototype had a large, single main wheel undercarriage (these being replaced by a four wheel bogie unit on production aircraft), together with four Ghost 50 Mk1 engines buried within the wings. The addition of a revolutionary pressurised passenger cabin facilitated high-altitude travel in absolute comfort.
Designed by R.E. 'Ron' Bishop (designer of the DH98 Mosquito) the DH106 Comet represented a new category of passenger travel and as such, it was subjected to extremely rigorous testing including both pressure and water tank trials.
The second DH106 prototype (G-5-2 / G-ALZK) flew just a year later, carrying out over 500 hours of flight test and route proving trials, with technical observers on board from interested International Airlines such as Qantas.
The first production aircraft (G-ALYP) flew on 9th January 1951, and it recorded the types first ‘fare-paying’ flight to Johannesburg with BOAC in May of the same year. The aircraft was an instant hit with the passengers including Queen Elizabeth II, the Queen Elizabeth, the Queen Mother and HRH Princess Margaret, who were all VIP’s on a special flight in June 1953.
The De Havilland DH106 Comet was heralded as the new age of commercial jet-powered air transport and many predicted that Britain would now lead the way in aircraft production around the world.
The DH106 Comet was only 93 feet in length, almost 15 feet shorter than its main competitor the Douglas DC6B.  It carried fewer people although this was in a significantly more spacious environment and BOAC opted to instal 36 reclining 'slumber-seats' with 45-inch (1,100 mm) centres thus allowing for greater leg room in front and behind. Air France chose 11 rows of seats with four seats to a row installed.
In the BOAC configuration, the large window and table seating gave a feeling of comfort and luxury, highly unusual for passenger air travel of the period. Other luxuries included a galley, serving hot and cold food and drinks, plus a bar and even separate men's and women's toilets. The structure also provided space for emergency situations including life-rafts, stored in the wings near the engines, and individual life-jackets were stowed under each seat.
One of the most striking aspects of DH106 Comet was the quiet, 'vibration-free flying' as publicised by BOAC suggesting that 'passengers more used to propeller-driven airliners would find the smooth and quiet jet flight a novel experience'.
DH106 Comet and Queen Elizabeth, The Queen Mother
HM Queen Elizabeth, The Queen Mother and Princess Margaret about to board a Comet in June 1953
Around 50% faster than the equivalent piston engine aircraft, scheduled flights from London to Tokyo on DH106 Comet took just 36 hours, compared to the 86½ hours recorded by aircraft such as the BOAC Argonauts, who had previously dominated the route.
In its first year, DH106 Comets carried over 30,000 passengers and at least 8 DH106 Comet flights departed London each week, destined for Johannesburg, Tokyo, Singapore and Colombo.  
Sadly, the history of the DH106 Comet 1 is dominated by the two devastating accidents. The first (G-ALYP) saw the aircraft destroyed off Elba in January 1954 and the second (G-ALYY) which disappeared near Naples in April of the same year.
Following the recovery of the wreckages, extensive investigation was carried out at the Royal Aircraft Establishment (RAE) Farnborough by the Air Accident Investigation Board (AAIB). It reported to the National Board of Enquiry that the primary cause was determined as catastrophic failure of the pressure cabin due to metal fatigue.  
It identified that despite extensive testing in the design stage, the cyclical pressurisation and subsequent depressurisation of the fuselage had accelerated the stress levels. This had caused cracks and fissures around the corners of the ADF, and some the main passenger windows, causing disastrous fractures in the structure and an almost instant failure of the airframe.
Previously, one aircraft (G-ALYV) had been destroyed near Calcutta in May 1953 although this accident was attributed to severe turbulence in a thunderstorm and not related to the Elba and Naples disasters.
With the identification of the structural problem inherent in the earlier series, all DH106 Comet 1 aircraft were withdrawn from service and the production line at Hatfield was halted.
De Havilland Aircraft Company set about relaunching DH106 Comet with a stronger, larger version of the aircraft whilst a small number of remaining aircraft were modified to DH106 Comet 1X or DH106 Comet 1XB standard, with a reinforced structure and (1XB) elliptical window apertures. 
One aircraft (G-ALYT) was also fitted with Avon 502 engines and larger intakes and appeared as the prototype DH106 Comet 2X.
De Havilland DH106 Comet 2X
De Havilland DH106 Comet 2X (G-ALYT) used for Crew Training at RAF Halton 1959-64
16 Production DH106 Comet 2 aircraft were manufactured for commercial use but with confidence in the type at an all-time low most were transferred to RAF service as the Comet C. Mk2 for Air Transport Command. 
Other examples meanwhile, served the RAF in electronic intelligence (2R) and training roles (T2) and a single Comet 2E (XV144) was used by the RAE for blind landing, head-up display and autopilot trials.
8 years had passed since the DH106 Comet first took to the air and during the period by far its biggest competitor had been busy developing the Boeing 707.  The US airlines opted for the home-built aircraft and the likes of Pan-Am introduced the 707 in October 1958 and this was soon followed y American Air Lines and Continental Airlines shortly afterwards.
As a measure of what had been lost was that Boeing produced 865 examples of the 707 during its operational life compared to 114 De Havilland DH106 comets across all four marks.
The Comet story does not end in the mid-1950s however as the Comet 3 and Comet 4 saw a re-birth of the type and their story is dealt with on a separate page.
The Comet 1 is widely thought to have been one of the biggest steps forward in aviation technology and design.
Despite the awful tragedies, one of the positive legacies will be the advances in techniques for air accident investigation which were the most extensive and ground-breaking ever seen.



Comet 1
13 Built
Production aircraft
Comet 1A
8 Built (1 scrapped)
Updated Comet 1 with higher weight and fuel capacity with water-methanol injection. All Comet 1A were recalled and were damaged in testing or were scrapped.
Comet 1X
2 conversions
Comet 1A rebuilt with heavier-gauge skins to a Comet 2 standard for the fuselage.
Comet 1XB
4 conversions
Comet 1A upgraded to a 1XB standard with a reinforced fuselage structure and oval windows.
DH 111 Comet Bomber
Not built
A nuclear bomb carrying design which received a negative evaluation from the Royal Aircraft Establishment.
Comet 2X
1 Built
Comet Mk 1 powered by four Rolls-Royce Avon 502 turbojet engines and used as a development aircraft for the Comet 2.
Comet 2E
2 Built
Comet 2 fitted with Avon 504's (Inner) and Avon 524's (Outer) and used by BOAC for proving flights.
Comet T2
2 Built
Comet 2 for the RAF as crew trainers.
Comet C2
8 Built
Comet 2 originally for commercial use but completed for use by the RAF.
Comet 2R
3 Built
Comet modified for use in radar and electronic systems development for the RAF to monitor Warsaw Pact signal traffic.


Specification (Comet 1)

Powerplant                             Four 4,450 lbst DH Ghost 50
Span 115 ft Maximum Weight 105,000 lb; (120,000 lb) 
Capacity 36 to 44 passengers
Cruising Speed 460 mph (400kn) 
Range (full load) 1,500 miles (1,300nmi / 2,400 km)



Comet 1A                             
RAF Museum, Cosford, UK                                                                 
A number of nose and fuselage sections are also preserved at Museums around the world.


Other information

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