Originally Posted by
Compton3fox
My concern with more aural callouts is that the brain may simply ignore them or hear what it expects to hear in what we suspect was a high workload phase. Good points made about my suggested protection for simultaneously feather of 1 and 2 in-flight. You would be able to feather 1 by one but not at the same time without doing something different to the normal process for feathering just before engine shutdown. So if you try to pull the condition levers when you meant to pull the flaps, chances are, you will use the process you normally use and you will not be able to move the levers. This would then prompt you to look down and see what was preventing them from moving which would show you your error. The process for a simultaneous airborne feather would be very rarely used so unlikely to be done subconsciously or via muscle memory. The risk is that if you did need to do it, would you remember how in the heat of the moment?
The counter to all this is, has this ever happened before? And how likely is it to happen again vs. the potential other things that could go wrong with such a change.
If you add a mechanism which under some circumstances prevents a propeller being feathered then you have to factor in the risk that a failure of that mechanism prevents feathering when you need it. Adding complexity generally has a downside that needs to be considered.