The History of the 'Trident' by David Maltby
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de Havillands original proposal, the DH121, was a larger & more powerful aircraft than the Trident ended up being. BEA signed a Letter of Intent in 1957, which gave the go ahead for the development program to begin.
A full family of aircraft with higher capacity & new upgraded engines was intended. The Government decided, before production started, to get the Americans involved in the extended project. A US deligation including people from Boeing was given full access to the plans, but nothing came of it.
Soon after, the Boeing 727 emerged & eventually took the market, with a very similar design to the originally planed DH121.
Before production of the DH121 started, BEA decided that the design had to be modified. Passenger numbers had been droping & although this turned out to be just a dip in an upward trend, BEA insisted that the aircraft be scaled down with a capacity of only 79. This also meant that the proposed engines were now not needed & Rolls Royce Speys were used instead. With the design modified, BEA finally made a formal agreement for 24 aircraft in 1959.
In 1960, de Havilland became part of Hawker Siddeley, in the Government forced mergers which also saw the creation of BAC. The HS121, as it became known, was also given the name Trident by the Chairman of BEA. The Trident first flew in January 1962 and appeared at the Farnborough Air Show soon after in BEA colours.
BEA took delivery at the end of 1963 & after crew training & route proving, it entered service in March 1964. The early Tridents were found to be a bit underpowered, particularly lacking in takeoff performance. BEA crews had joked that it only took off because of the curvature of the earth. The improved Trident 1E had more engine power & also had high lift slats fitted & a bigger capacity. Improvements proposed by BEA eventually led to the more successful Trident 2, with more powerful Spey 512s & a much better range. The first Trident 2 entered service in 1968.
When BEA decided it needed to replace its Vanguard & Comet fleets, several options were explored. The Trident 3, with a 16ft 5in stretched fuselage & seating upto 180, was the chosen route. Because of the lack of development in new engines, the limited engine power offered by the Spey was not enough & a small booster had to be fitted in the base of the tail. This gave either the option of a shorter take off run or an increase in capacity. The extra engine, coupled with an overall reduction in fuel capacity, meant that the Trident 3 had a much shorter range than the Trident 2. The Trident 3 entered service in 1970.
One thing that the Trident did have in its favour was the ability to land blind. The automatic landing system, developed with Smiths Industries, was finally given full CAA approval in 1972. However by this time the Boeing 727 was established as the market leader & the choice of most foreign airlines. Even so, 117 Tridents were built in total, with the last coming off the production line in March 1978. One notable sale was the 35 aircraft sold to the Chinese national airline CAAC. The Trident was CAACs first western built short haul jet airliner. BEA & British Airways always kept faith with the Trident & it became one of BAs longest serving aircraft, finally being retired early in 1986, after 22 years service. It is not known for certain, but it is believed that the Trident remained in service with the Chinese Air Force until the mid 90s.
Many of the retired Tridents were used as fire training aircraft at airports around Britain & some can still be seen in various states of disrepair.
Examples of all 3 Trident types are now preserved at musuems in England.
1C at Cosford, 2E at Duxford & 3B at Wroughton.
