The Trident was a fine plane. It was fully nose to nose to the 727-100 of the same era. In several ways it was ahead of its time, for instance it was the plane which pioneered Cat III landings.
It suffered from the engine choise. It's RR Spey engines were always on the small side, and probably caused by the RR collapse and time consuming recovery following the RB-211 troubles the Speys were never uprated to cope with stretched Trident versions. So when the 727-200 became available with uprated P&W JT8D-15 and -17 engines, then the Trident was wiped out of the competition.
The Speys were also extremely noisy - even more noisy than the JD8Ds on the 727!!! But that was hardly an issue at that time.
The very latest versions - designated Trident 3B, I think - actually had a fourth engine on top of the #2 engine. It was some small engine which RR developed as a vertical lift engine for an alternative design to the Harrier VTOL fighter plane which was never built. It gave some 5000 lbs extra thrust during take-off only. It was shut down at 2000 feet or so.
First time I was on a BA Trident - from CPH to LHR - then shortly after take off the F/A delivered me one of the major London newspapers with a smile. The fat headline news on the front cover was: "Yesterday it happened again! A BA Trident suffered turbine blade failure on one of its RR engines and aborted take-off at Heathrow". I immediately remembered that never before had I been rolling so far for a take-off at CPH. My captain had read the news too!!!
I did feel slightly more comfortable going back the following day on a SAS DC-9. Anyway I enjoyed several more flights on the Trident during the following years.
I think that it all proves that those Spey engines were simply pushed too hard to push the Trident.
It was a great plane. It deserved to have been fitted with JT8D engines. Nothing wrong with RR engines, however, neither new nor old ones. But exactly when the Trident needed improved and uprated engines, then RR was in a financial coma and could not deliver. P&W could, and that made the 727 a winner in a time frame when technological advances in aviation went much faster than today.
The BA Tridents were configured with backward facing seats on row #1. Therefore I always asked for row #2. That way it was easy to enjoy a pleasant conversation with fellow pax on #1 row, making the flight seem shorter.
Best regards, Preben Norholm
Always keep your number of landings equal to your number of take-offs