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TU154 out of Sochi is missing.

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TU154 out of Sochi is missing.

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Old 8th Jan 2017, 21:53
  #341 (permalink)  
 
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Mr K you are going to have to help us with that picture of the right wing - is there any portion of the movable leading edge (slat) visible? If so where is it and is it up or down?! Seems to me it's missing completely, which is interesting but not very informative. Thanks.
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Old 8th Jan 2017, 22:16
  #342 (permalink)  
 
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I THINK the AC went down nose first.
Guada just because an aircraft may have crashed nose down, that doesn't mean it wasn't (still) stalled -- especially at low altitudes without enough time/space to recover.

(As example here was Colgan 3407 in accelerated stall with extreme nose down position, 2 seconds before impact, stick shaker & pusher activated, from NTSB analysis):


Last edited by peekay4; 8th Jan 2017 at 22:34.
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Old 9th Jan 2017, 06:28
  #343 (permalink)  
 
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Originally Posted by gonebutnotforgotten
is there any portion of the movable leading edge (slat) visible?
Isn't there is a piece of the leading edge flap visible & retracted.
First look at Kulverstukas' pictures of the wing here: http://www.pprune.org/rumours-news/588730-tu154-out-sochi-missing-17.html#post9633883
and look to the left of the large hole in the leading edge. The airfoil profile seems to be complete there.
Next, look at this TU-154 picture to see the leading edge flap configuration.
(Note: It is a realllly big image, so I am just linking it) http://www.airlinereporter.com/wp-co...SC_1345-15.jpg
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Old 9th Jan 2017, 08:26
  #344 (permalink)  
 
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Machinbird

I've been studying all the pics of the 154 I can find and it's not obvious to me that the length of leading edge to left of the hole isn't just the fixed section behind the slat. It seems possible that the whole of the slat disappeared as one piece. If it did is it more likely that it was extended or retracted at impact? What does the left wing look like?
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Old 9th Jan 2017, 12:47
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@peekay4 # 344

I meant a stall position after an excess of angle of attack.
Note: I don't think could happen in this unfortunate case, in which I guess the AC went straight to water with an angle just opposite.
But this is MY GUESS. Time to investigators (if made public what happened, thing rather difficult being a military Russian AC).
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Old 9th Jan 2017, 13:50
  #346 (permalink)  
 
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Hola guadaMB,

Like lomapaseo I have never heard the expression "stall pose" in relation to an aircraft impact. I am thinking this may be used by personnel in your SAR work? Every profession has its own jargon. Did you mean "nose up"?

In case you do not know: in aeronautics there is a specific difference between "pitch attitude" and "angle of attack" (AoA, also known as "alpha"). When AoA is too high, the wing is stalled. As peekay4 and others have pointed out, an aircraft wing can be stalled even when the pitch attitude of the aircraft is nose-down. In that case, the rate of descent will be very great, but the aircraft will still have forward airspeed.

Hope this helps.
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Old 9th Jan 2017, 14:01
  #347 (permalink)  
 
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@Chris Scott #348

Did you mean "nose up"?



And I meant AoA in excess (this is not the case, as I think. The entire AC appears absolutely torn, washed off in pieces, besides it's a strong bird. Had to happen what you say: nose down, the rate of descent will be very great, but the aircraft will still have forward airspeed).
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Old 9th Jan 2017, 14:05
  #348 (permalink)  
 
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Quote from Machinbird:
"Isn't there is a piece of the leading edge flap visible & retracted.
[...] look to the left of the large hole in the leading edge. The airfoil profile seems to be complete there."

I see what you are looking at, but I think we need a closer look to tell if it is merely the leading edge behind the slat, as gonebutnotforgotten suggests, or a small length of retracted slat.
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Old 9th Jan 2017, 14:09
  #349 (permalink)  
 
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Photos from Sochi

Port wing?


Last edited by Kulverstukas; 9th Jan 2017 at 16:31.
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Old 9th Jan 2017, 14:24
  #350 (permalink)  
 
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Thanks again Kulverstukas,

Is that trailing-edge flap fully retracted?
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Old 9th Jan 2017, 14:38
  #351 (permalink)  
 
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No, it's around 15° I think
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Old 9th Jan 2017, 14:54
  #352 (permalink)  
 
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The leading edge slats seem to be in the deployed position on this side if that's not a result of impact damage. The trailing edge flaps is more difficult to say. On the far right end they look retracted, on the other side it is not as clear. The investigators will have more clues from the ballscrew positions. This wing has much less damage. The surf was higher as in the Hudson river and the impact was more violent, with no survivors left. The airplane was in any case too slow for a clean wing, so the investigators have to answer the question, how it came into the configuration indicated on the crashed remains.
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Old 9th Jan 2017, 14:56
  #353 (permalink)  
 
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In #164, @xeque asks laconically: Asymmetric flaps?
In #173, @Kulverstukas shows a wing with flpas fully retracted
In #351, @Kulverstukas shows the other wing with flaps "around 15º"

Could this asymmetry be the -not necessarily the only- cause of the tragedy?

Last edited by guadaMB; 9th Jan 2017 at 14:56. Reason: a lacking @...
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Old 9th Jan 2017, 15:00
  #354 (permalink)  
 
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the flap drive mechanism might be torn off by impact forces and the flaps lowered just by gravity on this photo, especially because on the first photo when the wing is lifted out of the sea in inverted position the flaps appear to be up.

i do not think we can learn much about the actual flap position at impact from these photos
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Old 9th Jan 2017, 15:24
  #355 (permalink)  
 
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It's almost impossible to move/loose flaps even if after a strong crash like this.
And if a section was left on the loose, the other ones would stay as when impacted.
Repairings are made with special wrenches attached at the motorized end of the screw mechanism.
And i think it's not the same wing...
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Old 9th Jan 2017, 15:53
  #356 (permalink)  
 
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good question , i would say the pictures on post 325 and 351 all show the same part of the starbord wing - in inverted position at the night photo when its lifted out of the sea. what do other here think ?
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Old 9th Jan 2017, 16:11
  #357 (permalink)  
 
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Kulverstukas,

With the photo of the back view of a wing in your post #351, you refer to it as the "sideboard wing". Excuse me asking, but do you mean the "larboard" (port) wing, i.e., the left (L/H) wing? If I had to guess, I would say it was the starboard (R/H) wing, but I am not sure.

I agree with aerobat77 that the wing on the ship re-posted on #325 is probably also the R/H wing. But we agree that the quay-side photo first posted in #325 seems also to be the R/H wing.

What are your thoughts? Have we seen the L/H wing yet?
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Old 9th Jan 2017, 16:27
  #358 (permalink)  
 
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Post #351 - seems port i.e. left wing top up faced us with trailing edge. (flaps cowling bigger right to left).
Post #325 - seems starboard wing i.e. right, at the far top side visible place of gears cowling torn off
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Old 9th Jan 2017, 16:37
  #359 (permalink)  
 
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Or if we agree that this is preliminary placement of lifted parts, it's still the same right wing just seen from other angle...

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Old 9th Jan 2017, 17:27
  #360 (permalink)  
 
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The wing showed in post #325 (night scene) is NOT the one in the BIG PICTURE.
The latter seems to be longer and shows almost to the tip.
The #325 pic wing is a part closer to the hull.

comment: impressive the last pic. Shows the magnitude of the impact.
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