@Vargas Fan the Trident was very much hobbled by early design decisions leading to a situation in which growth to meet customer needs led to, among other things, the plane getting a fourth engine, also in the tail.... The avionics were almost impossibly advanced for the era.
I remember hearing about the brief career of the four engined Trident (Quadrant?). The crash of BEA Flight 548 didn't help, with the sales of the American mid rangers like the 727 catching up. While in that case there seems to have been some issues with the design of the droops lever, it seems mainly to have been the fault of the autocratic Captain Keyes and his health problems.
I think 548 was an example of how CRM can save planes, yes.
Sadly a B-17 crashed today in Connecticut, engine problems and crashed just short of the runway.