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Old 03-08-2019, 06:37 AM   #41  
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Originally Posted by rickair7777 View Post
So you're saying you had alpha?

https://youtu.be/335GdTqtyLs?t=59
Thanks for re-hacking my Dos Gringos currency!
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Old 03-08-2019, 06:46 AM   #42  
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Originally Posted by ptarmigan View Post
I would add that many professional pilots *think* they would recognize a stall. Unfortunately the are mistaken, hence my article on the topic.
That’s a big part of the problem. With the exception of some military pilots most airline pilots entire stall experience is in light aircraft with straight wings. There stall characteristics are vastly different then a awept wing high performance jet. Most simulators have no fidelity in reproducing stalls and even if they could the violence that often accompanies a stall/departure from controlled flight in high performance aircraft will always be missing. Essentially we have no real training for the post departure regime.
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Old 03-08-2019, 07:01 AM   #43  
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My line of thinking is to avoid getting to the stick shaker in the first place. Airspeed decay due to distraction, bias, or fatigue is a common problem. I don't think adding an addition level to a warning system is going grind my gears like it will for some.
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Old 03-08-2019, 07:40 AM   #44  
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Originally Posted by sailingfun View Post
That’s a big part of the problem. With the exception of some military pilots most airline pilots entire stall experience is in light aircraft with straight wings. There stall characteristics are vastly different then a awept wing high performance jet. Most simulators have no fidelity in reproducing stalls and even if they could the violence that often accompanies a stall/departure from controlled flight in high performance aircraft will always be missing. Essentially we have no real training for the post departure regime.
And most airliners have different stall characteristics than swept-wing high performance jets. But having had the chance to see straight wing and swept probably gives a bit of advantage to mil pilots (that, and the fact that many airframe types actually do real-world stall training.)
For example, if I tried the rudder dance in a MD-88 or 717 at high AOA, it's not like it was in the high performance jets I flew in the military, and might actually shear off the tail in some regimes.
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Old 03-08-2019, 07:54 AM   #45  
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And most airliners have different stall characteristics than swept-wing high performance jets. But having had the chance to see straight wing and swept probably gives a bit of advantage to mil pilots (that, and the fact that many airframe types actually do real-world stall training.)
For example, if I tried the rudder dance in a MD-88 or 717 at high AOA, it's not like it was in the high performance jets I flew in the military, and might actually shear off the tail in some regimes.
All airliners I have flown have swept wings. The fear of shearing the vertical stabilizer is not a issue at stall speeds.
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Old 03-08-2019, 07:54 AM   #46  
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Originally Posted by sailingfun View Post
That’s a big part of the problem. With the exception of some military pilots most airline pilots entire stall experience is in light aircraft with straight wings. There stall characteristics are vastly different then a awept wing high performance jet. Most simulators have no fidelity in reproducing stalls and even if they could the violence that often accompanies a stall/departure from controlled flight in high performance aircraft will always be missing. Essentially we have no real training for the post departure regime.
The Colgan event was not a swept wing aircraft, nor particularly high performance, nor one of unconventional stall characteristics, nor did it lack for stall warning, nor cockpit data. All were present, all were active, all conventional.

The emphasis on training for airlines is stall avoidance. Renslow wasn't in a stalled state until he took the aircraft there, held it there, failed to increase power beyond partial, and continued to increase AoA throughout the evolution. This wasn't an accelerated stall, and it wasn't a tip stall or deep stall state in a swept wing aircraft, nor a stalled state in which aerodynamic control was limited, blanked-out, or reversed. It was entirely avoidable, and entirely recoverable.

Depending on circumstance, in a swept wing aircraft, especially in the arrival and approach phse, it's possible to force the aircraft into a state from which recovery is not possible in a swept wing aircraft, given the altitude loss that will be involved in recovery, in some cases. This was not the case with the Colgan flight.
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Old 03-08-2019, 09:32 AM   #47  
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Originally Posted by ptarmigan View Post
This is the common perception of this accident, and one I used to share as well. However, many pilots will simply not recognize a real stall when it happens to them outside of the training environment, and that is a sad fact. Reading it again, maybe we are not saying something so different. Once a person has created a mental model of the aircraft state confirmation bias kicks in so to that extent it true that they will ignore cues.

What I like about q-alpha is that it prevents the errant mental model in the first place. Ideally you have that an an AoA gauge that you are trained on.
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.
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Old 03-08-2019, 09:51 AM   #48  
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Originally Posted by sailingfun View Post
All airliners I have flown have swept wings. The fear of shearing the vertical stabilizer is not a issue at stall speeds.
It is an issue at any speed.
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Old 03-08-2019, 09:52 AM   #49  
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Originally Posted by Adlerdriver View Post
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.
The assumption is that if the aircraft had been barking airspeed constantly, the Colgan crew would have not taken the airplane to the shaker, and beyond. The Captain pushed the power to the 70 degree point, the pusher then broke the stall, but the FO put the flaps to 0. Clearly, the startle factor with confusion, was an issue in this accident.

For reasons of mitigating inadvertent activation, the stick shaker margin has been significantly reduced from its original design. In fact, in the patent, the auto-pilot was to remain on, and do the recovery procedure, not the pilot.
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Old 03-08-2019, 11:10 AM   #50  
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Originally Posted by Mesabah View Post
The assumption is that if the aircraft had been barking airspeed constantly, the Colgan crew would have not taken the airplane to the shaker, and beyond. The Captain pushed the power to the 70 degree point, the pusher then broke the stall, but the FO put the flaps to 0. Clearly, the startle factor with confusion, was an issue in this accident.

For reasons of mitigating inadvertent activation, the stick shaker margin has been significantly reduced from its original design. In fact, in the patent, the auto-pilot was to remain on, and do the recovery procedure, not the pilot.
The pusher didn't really break the stall - the CA fought it and won. 160lbs is pretty much a full panic pull. I don't think he knew he was fighting the stick pusher, I believe he thought he was fighting aerodynamic forces.

Quote:
After the first stick pusher activation, the captain applied a
41-pound pull force to the control column, and the roll angle reached 105° right wing down.
After the second stick pusher activation, the captain applied a 90-pound pull force, and the roll
angle reached about 35° left wing down and then 100° right wing down. After the third stick
pusher activation, the captain applied a 160-pound pull force.
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