Hi Chris,
Yes.
Failures on airplanes are based on a complex algortihm given factors like total miles flown, total passengers, days since last maintenance, etc ...
If an airplane has a failure, it can be a random failure. Electrical, Hydraulical, Engine, besides others.
Even if you have your failures turned off on fs2004/fs2002, we turn them on. The same applies to crash detection on airplanes and building, and crash due to overstress.
So, every flight is unique. You don't know what will happen. BUT, don't start thinking that everytime you fly you'll have a failure. No. Failures have a very very minimum probability to happen, even more than right now all of our airplanes are new so the reability coeficients are as higher as possible.
Regards,