Originally Posted by
CONF iture
Why such additional layer of uncertainty that yokes would naturally prevent ?
Because someone above either of our paygrades on both the pilot and engineering side decided that the benefits outweighed the drawbacks.
Think about it logically - the difference between looking over at the yoke to confirm what you're seeing on the ADI or out the window (unless you're watching your colleague's inputs like a hawk, which I suspect isn't the case given the average PNF workload) and asking them directly is what - a second, maybe two?
Also, pilots do silly stuff, let them do those by themselves, automation is here to help not to put you deeper in the mud.
And the autotrim does help - specifically it helps a pilot who is in manual control maintain the attitude he is requesting, and if the protections are available they keep the attitude within the flight envelope. Lose the protections and the autotrim will do it's best to keep up with demand, even if that demand is inappropriate.
As part of the research I was talking about, it is possible that the A320's equivalent of Alt 2 (Alternate with no speed stability) may function differently when it comes to trim, I'll keep you updated.
Let him trim by hand if that's really what he wants.
Which he (or she) can do by holding on to the trim wheel if he or she does not like what the autotrim is doing (although I have yet to hear of autotrim behaving inappropriately due to a software or hardware failure).