We don´t model failures as a feature. The few you can find now are remnant from our internal system-modeling tests that we decided to make available for everyone. So consider them a goodie, and the "missing ones" not really missing ;-)
A few of the default X-Plane failures work as well.
We plan to add more failures in the future - after completing the basic aircraft (FMS, 3D cabin, ...)
Cheers, Jan