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De Havilland
Comet 1 & 2

The first commercial jet airliner
De Havilland DH106 Comet 1 (GALVG) De Havilland DH106 Comet 1 (GALVG)
The De Havilland 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.
 
The first 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 large, single main wheel (these being replaced by a four wheel bogie unit on production aircraft) together with four Ghost 50 Mk1 engines buried within the wings and a pressurised cabin to facilitate high altitude travel in absolute comfort. Designed by Ron Bishop (designer of the DH Mosquito) the 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 prototype (G-5-2 / G-ALZK) flew 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 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, the Queen Mother and Princess Margaret who were VIP’s on a special flight in June 1953.  
 
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 equivalent piston engine aircraft, scheduled flights from London to Tokyo on 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, Comets carried over 30,000 passengers and at least 8 Comet flights departed London each week, destined for Johannesburg, Tokyo, Singapore and Columbo.  
 
Sadly the history of the Comet 1 is dominated by the two devastating accidents to G-ALYP, which was destroyed off Elba in January 1954 and G-ALYY which disappeared near Naples in April of the same year.
 
Following the recovery of the wreckage extensive investigation carried out at the Royal Aircraft Establishment (RAE) Farnborough by the Air Accident Investigation Board (AAIB) and it reported to the National Board of Enquiry that the primary cause was a catastrophic failure of the pressure cabin due to metal fatigue.  It identified that despite extensive testing in the design stage, the cyclical pressurisation and de-pressurisation of the fuselage had accelerated the stress levels around the corners of the ADF and some the main passenger windows, causing disastrous fractures in the structure and almost instant failure of the airframe.
 
Previously an 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 or Naples disasters.
 
With the identification of the structural problem inherant in the earlier series, all Comet 1's were withdrawn from service and the production line at Hatfield was halted.
 
De Havilland set about relaunching Comet with a stronger and larger version of the aircraft whilst a small number of remaining aircraft were modified to Comet 1X or 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 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 Comet 2's were for commercial use but with confidence in the aircraft 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.
 
The Comet story does not end there 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 a real step 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.

Variants

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's were recalled and were damaged in testing or were scrapped.
Comet 1X
2 conversions
Comet 1A's rebuilt with heavier-gauge skins to a Comet 2 standard for the fuselage.
Comet 1XB
4 conversions
Comet 1A's 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)

Survivors

Comet 1A                             
(G-APAS/XM823) 
RAF Museum, Cosford, UK
www.rafmuseum.org.uk                                                                 
A number of nose and fuselage sections are also preserved at Museums around the world.

More information