Connecting 2 pixhawk together for more safety

i use pixhawk 2.1 and it is very good autopilot but i want to use 2nd board for more safety
also i see one auto pilot that connect 2 of them together for more safety but it is good as pixhawk

i have some question :
1 . is any one connect 2 pixhawk together?
2 . did you feel need to use 2 autopilot , and is it make the flight safer ?
3 . and what is you tip to do this ?

It’s possible, but for full isolation you need to create your own PWM buffers.
Provided that you have done great job integrating the pixhawk, it is very unlikely to be the part to fail.

I agree with previous comment. In the many years I’ve spent on drone forums , I can’t remember a case where an Autopilot board failed during flight (if setup correctly). What is more likely to fail is a bad sensors integration/installation with bad vibrations, bad wiring, bad powering, etc.

yes I agree with you ,but i had a idea to have more safety ,
what abut use better IMU or AHRS in system did you thing can make the pixhawk 2.1 more safe ?