Regarding the 737-400 crash years ago, was the crew concerned by an engine vibration gauge, or some such gauge? Is it also true that the Flight Attendants never reported to the cockpit that something appeared to be wrong with one of the engines?
Onboard the 747 (400) which departed San Francisco not too long ago and had numerous compressor stalls etc in an outboard engine, the flying pilot used aileron instead of rudder as the plane wandered from its initial departure heading. The heavily-loaded jumbo jet barely missed a high hill off the departure end of the airport. The crew at the controls stated that there was so much engine vibration that it shook both flight instrument panels, which might have made the "rudder ball", or a similar indicator, very difficult to read. The extra crew onboard were shouting from the back, that the flying pilot must use rudder inputs, from what I remember.
This is not meant as criticism of any of those pilots at the controls, but haven't several major lessons been learned (not just more hand-flying currency for 747-4 FOs: both Captains fly so many legs on the very long flights that the FOs go to the simulator once each six months just for approach/landing currency...maybe even laymen can see the problem here) regarding both panel vibration and CRM from the cabin, so that cabin crewmembers don't just assume that the engine gauges in the cockpit always reflect what can be seen or heard from some passenger windows?
Years ago at least six of us were ferried with flight bags in a very full Navaho from "Branch of Peace" airport up to Dubuque, Iowa, in order to ferry a few repossesed Bandeirantes back on a clear day. Two of our pilots, after takeoff, figured that our plane had been overloaded by about 800 pounds. The FBO owner (J. *.) was not known to be the most conscientious, and very many Part 135 airplanes would not have had a positive climb rate even with the correct engine feathered etc, at max gross weight-we could have ended up as dead meat. Do you think that the pilots on that flight would have refused to takeoff far overweight, if their jobs were at risk? A very young pilot who later ferried one of the Bandits solo had reportedly never even flown the type, which often required type ratings in the heavier series.