I found a few on Avsim (login required for download)...
Nasty Control Center V1.0 (FS2002)
File Description:
Allows more 'random' failures and recovery over a longer time period than MS System Failure. Define your own kind of failure like a fuel leckage.
DownloadRandom Failure v1.0 (FS2002 & FS2004)
File Description:
This is a random failure generator for MS Flight Simulator 2002 and 2004. It relies on Flight Simulator's built-in failure system, but does not requires the failures to be "planned" each time you start a flight. When Random Failure is running, just expect one or several failures to happen at any time, with a configurable probability. Random Failure is currently able to generate the following failures : altimeter, attitude indicator, mag compass, fuel indicators, direction indicator, vertical speed indicator, ADF, NAVs, COMs, transponder, first engine, pitot, vacuum and electrics. Needs FSUIPC (registered for FS2004).
DownloadAlert!! Lite v1.0 (FS2002)
File Description:
Alert!! Lite is the freeware version of Alert!! Pro, which will be available at the end of May. Alert!! Pro is a professional pilot fault monitoring system and complex failure generator expansion pack for Flight Simulator 2002. The program tries to satisfy the dream of almost all virtual pilots, to simulate the failure of various systems and instruments in player’s aircraft as close to real-life as it can be. For first time in Flight Simulator, pilots can try for example what happens when extracting landing gears or flaps over the allowed speed. With using Alert!! Pro airplanes must be operated within operational limits, otherwise the plane can suffer serious damage or can even lead to crash. With this program we created the real hard simulator flight which stands closer to reality than anything before. This is the dream of all virtual pilots. Alert !! Pro is simulating runway condition according to weather conditions, so brake effects are depending on the condition of the runway. Alert!! Lite and Alert!! Pro damage modelling is a complex system in the program, so damages will have effects on each other. For example an engine explosion shall cause the failure of flight controls too. The program can create and handle many kind of failures. Player can set the frequency and even properties of various failures in an user-friendly interface. Visite our website for more information:
http://www.flytechsoft.com DownloadFS Reliability Factor v1.6 (FS2004)
File Description:
FS Reliability Factor is a failure simulator which allows you to set the reliability percentage (based on flight time) for over sixty flight simulator sub-systems grouped in seven system categories: Autopilot, Control, Electrical, Engine, Fuel, Instrument and Radio. It then uses these reliability factors to simulate sub-system failures during flight. Reliability Factor is useful for people who would like to enhance their flight sim experience with a slight (realistic) chance that something might go wrong during their flight. It can also be set up to guarantee a failure, or a number of failures, during a given time period.
DownloadHope this helps.