PPRuNe Forums - View Single Post - AF 447 Thread No. 12
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Old 14th Oct 2014, 22:59
  #637 (permalink)  
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Join Date: Jun 2009
Location: florida
Age: 81
Posts: 1,610
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Awwwwww, man! After all these years I read from an esteemed contributor

Right, but isn't a neutral stick effectively zero elevator demand? I'm probably missing something here
In these cosmic FBW jets, the control surfaces move wherever they have to in order for the jet to achieve the "trimmed" or "desireable" gee. Not attitude or bank angle or speed, but a mix of rates, gee and maybe AoA.

Okie has tried to explain a lot of this with a mix of pilot lingo and engineer stuff ( and I think he had some Bk 10 Viper experience). I tried from first seeing the wreckage photos and then data recorder traces. Looked like a classic deep stall impact. The c.g. charts I then got showed it was damned near impossible to get into a "deep stall". "deeply stalled" was possible when in reversion modes such as AF447.

So I abandoned the "deep stall" line of reasoning and tried to see how to stall the jet that many believed could not be stalled. Turned out to be the same techniue as with the Viper. Achieve a decent pitch attitude, run outta airspeed faster than the manual or "protected" laws and control surface deflections can work to achieve the desired gee/rate and voila!

P.S. @Winner synthetic speed and use of AoA indications prolly shoul be on thread of its own.
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