As avionic type haas quoted me as a Boost engine wizz!! I should point out that the biggest problem we had with them was lack of use, resulting in the fuel draining back to the centre fuel tank. This required the fuel system to be bled, my dodge was to bleed it but instead of doing a blow out to clear the residual fuel out of the system, was to replace the fuse & go straight for a start & most times that would fix the problem. I do recall that the run procedure was via the control switch on the overhead panel which could be selected to the rpm required, "eg" idle, climb & take off.
Wookey has commented on the crewing for the Trident. It was a very complicated aircraft & very advanced for it`s time. However in BEA (Best Ever Airline) we flew with a third pilot, other airlines like Northeast used a Flight Engineer. Their main task was monitering the systems as any failure had to be dealt with manually, "eg" generator or hydrualic failure.