Originally Posted by
Adlerdriver
ptarmigan,
Q-alpha video:
A circle of lights changing color and a mechanical voice calling attention to an airspeed problem.
What's the difference between that and either (or both) PF and PM noting the airspeed problem on their airspeed indicator while the PM constantly repeats "airspeed" until a correction?
Same question for the stall recognition and entry into stick-shaker. How is the "errant mental model" going to be prevented any more effectively? Why is a voice announcing "stall" and a red circle of lights is any more effective than a stick-shaker, airspeed indicator in the red-zipper and pitch at the PLI.
Pilots manage to ignore audible gear warning systems now and then. I don't see why this system is any different. It seems to me that it has the potential to put the PF or perhaps the whole crew into audio overload as they try to communicate effectively to resolve the situation with that thing blaring constantly in their ears.
Q-alpha warning starts quite a bit earlier as it is looking at both q and alpha, independently. The actual margin prior to stall for just an alpha based system is quite low.
Essentially the q-alpha would alert quite a bit earlier. As I recall from his SETP presentation, the system would alert significantly higher than a system based solely on alpha, I think the numbers were something like 30% over Vs as opposed to around 9% for current systems.