It's a shame this has deteriorated into a slanging match. I'm sure all parties are correct to a certain extent. My understanding is that roll back is a very real but also rare phenomenon occurring in very specific conditions. The RJ is not effected by it. The information is readily available from BAe and all companies should give extensive training in avoiding the conditions that can cause it. engine mods remove the problem all together. Similarly the pitch oscillation problem is an ice related condition which is real but rare and not as deadly as the ATR control reversal problem for example. Not deadly at all in fact and a fix has been found. The air quality issue is again quite openly publicised and the All Operators Memos from BAe cover the causes and the solution in detail. Incidentally they have also just discovered a possible problem with nose wheel centring on landing related to incorrect oleo charge. The information relating to all these problems, including a list and analyisis of all incidents is readily available so why not do some sensible research instead of wild speculation? By the way you might not be aware that some ERJ 145 operators have experienced air contamination problems. That aircraft also has a pitch trim problem. Name any aircraft that does not carry some mods to compensate for post production problems and someone will pop up to correct you. What matters is that the Manufacturer works with the Authority and the Operators to get them fixed, either by modification,operating procedure or both.