DH-106 Comet

Where the Comet 2 had been a Series 1 adapted to take the Rolls-Royce Avon engine, the Comet 3 was an altogether larger and improved aircraft. The first announcement of the Comet 3 was at Farnborough in September 1952, for introduction in 1957. It would be 15 feet longer than the Series 2, offering a variety of seating arrangements from 58 to 76 passengers. An improved Avon, now with annular-ring combustion chambers, raised the thrust of each engine from 7,300 to 10,000 lb, fuel capacity would increase by 20%, and the all-up weight would be 150,000 lb.

BOAC ordered five of the new aircraft, in addition to their other orders, and Pan-Am ordered three, with an option on seven more. This was regarded as a landmark, and expected to trigger sales to other American airlines. Needless to say, this all evaporated after the tragedies at Elba and Naples.

A single Comet 3 prototype, G-ANLO, was built. Its construction straddled the start of the crash investigation. Although it was too late to incorporate major structural change, it was given oval windows and the exhausts were canted away from the fuselage. Aerodynamics and systems

would be identical on the Series 4, and a lot of development work could usefully be done on G-ANLO, minimising delays. In fact it managed 80% of certification, and the first commercial flight of a Comet 4 was on 2 October 1958, only one year after the intended introduction of the Series 3.

The Series 3 (and particularly the Series 4) was so different to the Series 1/2 that there was a suggestion in government that the name should be changed. This was rejected by both de Havilland and BOAC, who were keen to restore the Comet’s reputation, not to bury it.

G-ANLO remained at de Havilland for conversion to “B” specification, with shorter wings and without its distinctive pinion tanks. After that, it passed to the Ministry of Supply under a new registration, XP915. It continued with its development role, becoming one of four aircraft types used at the Blind Landing Experimental Unit (BLEU) at RAE Bedford. In 1964, it was used to evaluate the Comet as a potential replacement for Avro Shackletons, used by RAF Coastal Command. A particular attraction was the Comet’s ability to dash quickly to a target, and then to fly slowly for long enough, or “loiter” over the target.