Regarding the QRS-11 solid state gyropscope. I think a bit of explanation is helpful.
This device controls the autopilot via inertia data, that is fed into it from accelerometers on the aircraft. The QRS-11 uses that inertia data to help the autopilot know where it is in 3D space and to fly the plane.
It follows, therefore, that if you feed the QRS-11 false intertia data (all devices have a backdoor and the QRS-11 is no exception. It could in theory be used to allow an aircraft to be taken over and flown remotely, e,g, in the case of a hijack) then the aircraft loses its sense of position and control is lost, as the autopilot has no data to tell it where it is, it gets disoriented. Give it a false height reading higher than the current position and the autopilot flies the aircraft into the ground trying to compensate.
Now do you understand how the QRS-11 could be used to bring down an aircraft?