Epic LT down at Spruce Creek, 2 fatalities

CFI A&P said:
There is a difference between rolling from torque and an inverted spin. Rolling from torque is an issue with WWII airplanes. Crashes from go-around and missed approaches are often located where you describe the TBM accident sites. The large horsepower aircraft also have other characteristics, such as they require right rudder during left turns, due to the left turning tendencies being more significant than adverse yaw. Not so much in a O-200 powered one fiddy or something larger that is equipped with a yaw dampener.
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I guess I see it as a question of weight to torque ratios. I will wager that the ratio of thrust to weight between an epic and, say a P51, are similar.
 
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Crop Duster said:
There was a TBM deal at MWC about a year ago. Report wasn't out last time I checked, but I'm going to go with probable cause: pilot error. The pilot error? Full power for go around at low speed, high AOA and insufficient rudder application resulting in near-ground torque roll into the infield. It's a problem in any high power-to-weight single. But still, in @CFI A&P 's defense, that's not an inverted flat spin.

Edit: after writing this I scrolled to @CFI A&P 's post. He needs no defense help. He well made his own.
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I think the PC-12 has the same problem, but they put a stick pusher in it to help keep it from happening.

This video is popular with them doing the testing.

 
z987k said:
I think the PC-12 has the same problem, but they put a stick pusher in it to help keep it from happening.

This video is popular with them doing the testing.

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All the kings stick pushers and all the kings men wouldn't help humpty dumpty in a near-ground torque roll situation. The stick pusher helps the insensate prevent stalls and/or spins. The torque roll can involve a stall condition in which case it more or less becomes a snap roll, but a torque roll does not have to involve a stall condition, nor likely do most near-ground torque rolls. The torque roll is induced simply by the massive twisting motion of the prop exerted on the airframe to which that prop is connected. The airframe -at low speed- isn't generating enough aerodynamic forces to counter the force of the prop torque. Thus, the force of the prop wins and the whole connected body of prop and airframe start twisting (rolling) with the prop... and at that slow airspeed, there is not a damned thing one can do about it except to keep the wheels on the ground. That connection between the wheels and the ground provides the only counter rotational force available at that slow airspeed. The situation for a pilot not aware of this phenomenon is insidious. They'll push up the power with the brakes applied, start to roll, and pitch up before reaching an airspeed sufficient to counter the rotational force. The second the wheels leave the ground the plane starts to roll for no apparent reason. If you're lucky, you'll notice the rolling moment (and it's causal over-power-for-the-airspeed condition) as the weight starts to come off the wheels. You will then keep the wheels on the ground and reduce power. But if you are not trained in the dynamics of the torque roll, if you did that it would likely be due solely to luck, or a good instinct to keep the airplane on the ground when an inexplicable control situation exists. And that's in a "normal takeoff" scenario. Now imagine a go-around. You're coming in slow, high AOA, low airflow over the control surfaces, no wheels on the ground. Then you smash in over 1000hp of power. Over you go.
 
Those Pilatus drops aren't torque rolls- most of them break to the right. I think it's mainly to do with wing design that is awesome for low speed flight until it decides to unload and leave you with...that. The -12 is a surprisingly docile go-around bird if you don't smash in the power.


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gotWXdagain said:
Those Pilatus drops aren't torque rolls- most of them break to the right. I think it's mainly to do with wing design that is awesome for low speed flight until it decides to unload and leave you with...that. The -12 is a surprisingly docile go-around bird if you don't smash in the power.


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To be fair even a 172 will get away from you on a go-around if you don't do some of that pilot shizzle. Which, uh is part of being a pilot.
 
+1 on Crop Duster's post. The TBM torque-roll is certainly eye opening. Actually it downright scared me senseless, particularly as we didn't even really seem to be that close to the stall.

Bp244
 
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