Originally Posted by Mansfield
Flight Test Guide For Certification Of Transport Category Airplanes, never refers to a stick pusher as a stall “avoidance” device.
That might as well be true, sir. Yet it is written in The Book, page132:
Originally Posted by DP Davies
It follows from all these considerations, therefore, that the stick pusher must always prevent the natural stall being reached in service.
However, I was wrong claiming that pusher is not a warning device; I simply considered forward movement of the column to be secondary effect of pusher acting. It is not as trivial as that. Pusher both prevents the stall and warns.
Originally Posted by DP Davies
If a stick pusher is used to meet the stall requirements it must provide two qualities: clear and unmistakable identification of the stall, by a sharp positive forward movement of the control column, and an adequate nose down pitch by the aircraft.
Nevertheless, I still consider that appeals for modifying or omitting the stick-pushers come from people unable to perceive that there are hard, insurmountable aerodynamic limits. Inability to tell saviour from killer comes into play, too.
Originally Posted by Pool
We all know about the shortcomings of big props in severe weather (ATR72 Q400). Was there ever a major grounding and redesign?
We don't know and you assume incorrectly. Icing on big props is a known quantity, there are equipment and procedures that enable to deal with icing safely. ATR was practically grounded after Roselawn, boots got redesigned, yet the ailerons were not. Instead ATR drivers were told that they need to push when faced with unusual roll behaviour in ice. I spent six winters in ATR and wasn't really uncomfortable with that. As far as I can tell, Q400 tolerates ice quite well (nb: that is not to say that one can approach icing lightly in Q400, one can't in any aeroplane). For the n-th time: the Buffalo accident was not icing related, except for INCR REF SPEEDS switch. If there was any ice on the airframe at all, buildup was so small that id did not affect the aerodynamics of the aeroplane. This fact was known a couple of months after the accident, yet lot of people simply glossed over it.