It was probably a heart attack or stroke. This can happen, and even though it's rare, you don't want to be onboard if the only pilot becomes incapacitated.
I don't know how to land a Citation.
I could take off using the Microsoft simulator, but I crashed every landing but one, and I still went off the runway. Don't count on me.
The beauty of MS Fsim (and I am an addict) is that you dont have to land one, the big jets pretty much land themselves. Type in the VOR freq. for the runway, set all the autopilot options, align airplane along the glide slope, and you are done.
Once you touchdown, set spoilers up, reverse thrusters and apply brakes, you should not overshoot the runway. Unless its a big plane on a small strip.
The best kept secret in the airlines industry is there are no pilots who can actually take off and land those things, thats why there are always two in the cockpit. One guys only knows how to take off and the other guy only knows how to land.
Hopefully you'll never have to fly on the one where they goofed in the pilot scheduling and scheduled only two takeoffers or two landers.......