In a bit of a different note, FAA and EASA have two different approaches for Flight Simulators. All licensed FSs according to both regulations should have certain basic common requirements such as the components related to "flying" ex. yoke, trims, flaps, etc And engine controls, radio communication, lights, engine start-up systems, landing and a few other requirements are mandatory.
With FAA, they allow some sort of a relief as a basic PC based desktop simulator can be used to log hours officially. but for this your hardware and software in the computer needs to be authorized by FAA.
But when it comes to EASA,they do not allow such desktop based products to log hours. According to EASA, they require an enclosed cockpit with feedback mechanism and quite a few other simulated requirements which FAA does not demand.
Software used in FAA approved desktop product can be even Microsoft Flight Simulator, Xplane, Lockheed's Prepar3d but with NO extra plugins such as weather, textures installed! and the frame rates are match and set by the manufacture. if you amend any of the defined criteria your licence is invalid. And some of the PC based FS manufacture also have their own software developed and any airport can be modeled on request.
But with EASA, the simulator manufacture have their own software or have a very selective customized software only for requested airport/countries/approaches or all the world! that you can specify. For example the A320 simulator from a popular European manufacture has their own software and their hardware - exact replication of the A320 cockpit.
Now when it comes to simulating mal-functions, failures (not sure about bugs though) almost all of the abnormal events are simulated in a professional commercial trainer. But you have a point, I do not know if a situation like the A320 nose gear landing with 90` angled could be simulated! and consequences could be judge from. But the point is when you train for any possible problem solving mechanism within the given time referring the FCOM or any other material and follow the steps or dealing with the situation with your own "airmanship" if nothing works come with the amount of training. when you encounter a failure in a system your training for other failures come into action and act like a background problem solving system to rectify the new problem!
Code0