de Havilland Comet – The World’s First Commercial Jetliner

de Havilland DH-106 Comet

The De Havilland Comet was the world’s first commercial jet airliner making its first flight on July 27, 1949. A new age in passenger travel was ushered in when BOAC entered the aircraft into service in May 1952.

It was a great source of pride for the United Kingdom which was lagging behind in commercial aircraft development following World War II.

When the first prototype was flown, it was immediately apparent that the type would set new standards for both flight performance and passenger comfort.    

The aircraft had a pressurised cabin, was quieter than the other passenger aircraft of that era, and powered by four jet engines buried within the wings.

Being the first commercial passenger jet, it was subjected to extremely rigorous testing including both pressure and water tank trials.  

The second prototype 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 flew on January 9, 1951 and then in May of the same year, it entered service with a flight to Johannesburg.

The aircraft was so popular that Queen Elizabeth, the Queen Mother and Princess Margaret who were among other VIPs on a special flight in June 1953.    

With the introduction of the Comet, flight times were slashed in half with scheduled flights from London to Tokyo taking just 36 hours compared to the 86½ hours on the BOAC Argonauts which previously plied 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.    

BOAC Comet 1 at Entebbe Airport, Uganda in 1952
BOAC Comet 1 at Entebbe Airport, Uganda in 1952

Disaster

With all its glory, the Comet sadly had devastating accidents in January 1954 near the island on Elba, and then three months later when another Comet disappeared near Naples. Both aircraft had departed Rome.

Investigators from the Air Accident Investigation Board (AAIB) found that there were catastrophic failures of the pressure cabin due to metal fatigue.  

The passenger windows on the aircraft were square, and the cyclical pressurisation and de-pressurisation of the fuselage accelerated the stress levels around the corners, causing fractures in the structure and almost instant failure of the airframe. Also, the thickness of the aluminium fuselage was similar to that of a credit card.

A previous Comet accident in 1953 near Calcutta attributed severe turbulence as the cause of the crash and not related to the Elba or Naples disasters.  

With the structural problems identified in the Comet 1, they were all withdrawn from service and the production line at Hatfield was halted.  

Relaunch

Taking the lessons learned from the crashes, de Havilland relaunched the Comet with a stronger and larger version of the aircraft while some of remaining aircraft were modified to Comet 1X or 1XB standard with a reinforced structure and elliptical window apertures. 

All production Comet 2s were also modified to alleviate the fatigue problems, with even more engineering upgrades in the Comet 3 and 4.

Development flying and route proving with the Comet 3 allowed accelerated certification of what was destined to be the most successful variant of the type, the Comet 4. The Comet 4 which was based on the Comet 3 but with improved fuel capacity, first flew on 27 April 1958 and received its Certificate of Airworthiness five months later.

With the Comet 4, BOAC was able to inaugurate the first regular jet-powered transatlantic services on 4 October 1958 between London and New York, but by the end of the month, rival Pan American World Airways was flying the Boeing 707 on the same route.

Both the Boeing 707 and the Douglas DC-8 jets were larger, faster, had longer ranges and were more cost-effective than the Comet. The American manufacturers as well as others benefitted from the lessons learned from the Comet accidents which were freely shared by de Havilland.

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