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Old 10-20-2009, 09:33 PM   #1 (permalink)
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Default Horizontal Stabilizer (Tail) Stall Warning

Greetings,

Just a thought; If wings can stall, and therefore have stall warning devices on them, why not on the tail? A tail stall is rare, but quite dangerous, and mixing up a "regular" stall from tail stall is deadly.

I don't want to dig too far into the Colgan loss, but maybe if the aircraft had installed BOTH wing and tail stall warning vanes the crew would have been able to accurately differentiate between the two stalls and apply appropriate stall recovery.

This is an 'easier said than done' issue I realize, BUT---the importance of such a system cannot be overlooked especially for Flight Into Known Ice aircraft.

A tail stall warning device would stack the deck in OUR favor.

With honor and respect for the Colgan passengers AND crew,
block30
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Old 10-20-2009, 09:43 PM   #2 (permalink)
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Originally Posted by block30 View Post
Greetings,

Just a thought; If wings can stall, and therefore have stall warning devices on them, why not on the tail? A tail stall is rare, but quite dangerous, and mixing up a "regular" stall from tail stall is deadly.

I don't want to dig too far into the Colgan loss, but maybe if the aircraft had installed BOTH wing and tail stall warning vanes the crew would have been able to accurately differentiate between the two stalls and apply appropriate stall recovery.

This is an 'easier said than done' issue I realize, BUT---the importance of such a system cannot be overlooked especially for Flight Into Known Ice aircraft.

A tail stall warning device would stack the deck in OUR favor.

With honor and respect for the Colgan passengers AND crew,
block30
The various types of stall warning systems for angle of attack on the wing may not be very accurate in icing conditions. It seems that tail stall accidents/incidents are more prevalent in icing conditions. A tail stall warning system would be subject to the same inaccuracies from icing conditions and therefore probably wouldn't give you good info just when you need it the most. Just my guess.
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Old 10-20-2009, 11:35 PM   #3 (permalink)
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It seems that tail stall accidents/incidents are more prevalent in icing conditions.
Thats because a tail stall happens more readily during icing situations. It is for that reason many aircraft have a lower flap setting used for icing conditions to reduce the disrupted flow over the tail. Too bad those folks hadn't taken a class on that, or had the experience.

As for inaccuracies, I can only speculate, but I would assume if they developed the system those inaccuracies would and could be accounted for.
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Old 10-21-2009, 07:55 AM   #4 (permalink)
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I don't believe the colgan crew thought about a tail stall, much less tried to recover from one. I'm not sure either of them even knew there was such a thing as a tail stall.

I also don't think they had a tail stall...they just got real slow.
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Old 10-21-2009, 08:15 AM   #5 (permalink)
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I don't believe the colgan crew thought about a tail stall, much less tried to recover from one. I'm not sure either of them even knew there was such a thing as a tail stall.

I also don't think they had a tail stall...they just got real slow.
The evidence does point to a plain old wing stall versus tail stall, but what did the crew think was happening? Most importantly can we prevent other crews from thinking the wrong thing?

I just read an article that said the captain had watched NASAs icing video a few months previously. And for anyone who has watched that video, a large segment is dedicated to tail stalls.

I know particularly the video discusses a sign of tail stall is buffet in the controls versus an airframe buffet. Did the pilot confuse the shaker with a control wheel buffet? I don't know. I think he is being written off as an idiot waaaay too easily from our spot here on terra firma.

God bless.
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Old 10-21-2009, 08:20 AM   #6 (permalink)
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As far as inaccuracies due to ice; The wing stall warning system needs to be heated correct? Does that stall warning system work well in icing conditions?

I'm sure that is hard to tell because not many people have gotten truly close to stall in real icing conditions!

But I would think the same principle would apply to a tail stall warning device. The warning device should be heated.

Once again easier said than done, but it sure seems like a great cost to benefit ratio if these would be installed.
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Old 10-21-2009, 03:47 PM   #7 (permalink)
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The evidence does point to a plain old wing stall versus tail stall, but what did the crew think was happening? Most importantly can we prevent other crews from thinking the wrong thing?

I just read an article that said the captain had watched NASAs icing video a few months previously. And for anyone who has watched that video, a large segment is dedicated to tail stalls.

I know particularly the video discusses a sign of tail stall is buffet in the controls versus an airframe buffet. Did the pilot confuse the shaker with a control wheel buffet? I don't know. I think he is being written off as an idiot waaaay too easily from our spot here on terra firma.

God bless.
They INCORRECTLY reacted to a stall warning. Specifically, they did EVERYTHING OPPOSITE of wha you would want in a wing stall recovery.

So, the more important question is, how do we get crews to succesfully identify and react appropiately to WING STALLS?

Why are people so stuck on the tail ice problems? It has NOTHING to do with this accident.

This accident was about a complete lack of professionalism in the cockpit, a complete loss of situational awareness, and the pilots incorrecty reacting to an aural and physical warning system that was trying to alert the pilots to the rapid loss of airspeed.
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Old 10-21-2009, 06:45 PM   #8 (permalink)
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Playing devil's advocate here;

Let's look at this another way, the crew did everything correctly for a tail stall (possibly minus the full power). Was that just coincidence or did they believe there was a tail stall?

Did the crew mis-diagnose the problem? Obviously. Would a tail stall warning device help others in the future? That is the main point.
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Old 10-21-2009, 08:06 PM   #9 (permalink)
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Playing devil's advocate here;

Let's look at this another way, the crew did everything correctly for a tail stall (possibly minus the full power). Was that just coincidence or did they believe there was a tail stall?
It would be nice to give them the benefit of the doubt on that, but all the information taken together indicates a complete lack of situational awareness. Fatty is correct unfortunately.

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Did the crew mis-diagnose the problem? Obviously.
I don't think they diagnosed anything at all. If the CA concluded he had a tail stall, which is a very unusual aerodynamic condition, he would have told the FO so that she would know why he was doing all the wrong things relative to their training.

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Would a tail stall warning device help others in the future? That is the main point.
It might help somebody in the future, but it will not be mandated without a new smoking hull accident which can be attributed directly to tail stall. I don't think colgan is going to qualify.
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Old 10-21-2009, 08:54 PM   #10 (permalink)
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That's too bad. Further, there is likely no company who will pony up the money to take the initiative in this realm. A tail stall warning system *seems* like a fairly simple risk management tool that could clear up confusion at a very critical time. At least in my mind the system would.
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