Originally Posted by OG
you cannot abandon the handling requirements altogether, so there must be something there appropriate to the failure probability level
I must admit that I'm not expert on this, but I believe system failures are addressed in FAR/JAR 25.1309. The general principle is that there must be an inverse relationship between the probability of a failure condition and its effect on 'continued safe flight and landing' of the airplane. This implies that an assessment must be made of the ability of the pilot to deal with the effects. The FAA and EASA have both published extensive guidance material on how this principle is to be applied.