Trident 1s were re-engined in the 60s iirc.
Hot summers day take off weight limited out of home base.
Infamous incident T3 out of Malaga lost a donk and diverted to Madrid as a larger station without anyone checking the missed approach climb/ WAT limits. As often happened incompetent controller lined up an Iberia which led to a missed approach going down hill; skipper then on the ball..pointed nose down towards lower terrain, accelerated, cleaned up and did a circuit: the Trident on approach was well on the back side of the drag curve.