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A Sukhoi superjet 100 is missing

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A Sukhoi superjet 100 is missing

Old 10th May 2012, 10:36
  #141 (permalink)  
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with some image enhancement, the initial impact witness mark appears quite flat relative to the steeply rising terrain, the sweepback angle of both wings apparently evident with foreshortening of the starboard wing "shadow" compared to that of the port.

Further up the slope, displaced slightly to port side of the nominal flight axis, what appears to be a tail-cone, and further up the debris field foliage discolouration roughly consistent with the symmetry, shape and size of the tail surfaces.

Discolouration to trees and ground cover appears to start at POI, and continue to those on the apex of the ridge, once again the center-line of this runs towards the top centre left of the image.

Two features which appear to be heavily damaged tree trunks to the centre right, one is above the POI, the other below.
There is heavy scoring of the surface below POI (landslide) which continues out of frame.

Last edited by Teddy Robinson; 10th May 2012 at 10:53. Reason: confirmation bias removal.
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Old 10th May 2012, 10:49
  #142 (permalink)  
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Concerning the TAWS - I could imagine that it shows FAULT because the IRSs are not aligned - I wonder whether the TERRAIN button is actually a terrain inhibit switch?
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Old 10th May 2012, 10:58
  #143 (permalink)  
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I see that both the TAWS switches are showing FAULT, which is a normal indication when the airplane's on the ground and not ready to fly. I was referring to the TAWS - terrain switch, which is clearly indicating OFF in white as well, that being a selected position. Or at least, I'm fairly confident in saying that the SSJ likely follows the standard amber=fault, white=selected button philosophy as do similar aircraft like Airbus and Embraer.

I've been racking my brain but for the life of me, I can't remember "GPWS/TAWS switch OFF" being an SOP for anything I've flown before in any normal phase of operation.

Last edited by thepotato232; 10th May 2012 at 12:06.
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Old 10th May 2012, 10:59
  #144 (permalink)  
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Is it possible that if they wanted to get up close and personal with the terrain in order to "demonstrate" the aircrafts capabilities, the crew would want to inhibit the TAWS/GPWS in order to silence the warnings ?? Of course more likely to select that option temporarily in the air which would not explain the prior posters overhead panel question.
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Old 10th May 2012, 11:05
  #145 (permalink)  
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That may well have been the case also, rmac, which is just as bothersome. Of course, it is far too early in the process for this little bit of speculation to have any weight to it. We don't know if the switch being like that is normal on this aircraft, and we don't know what the switch selection was on the accident flight. All we know is that these unfortunate souls ended up where they did, and with the aid of a modern GPWS/TAWS, that should not have happened.
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Old 10th May 2012, 11:39
  #146 (permalink)  
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...and does the EXT PWR being AVAL/ON indicate anything to those leaping to conclusions?
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Old 10th May 2012, 11:42
  #147 (permalink)  
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AS ALREADY STATED, it indicates that the plane is on the ground. And AS ALREADY ASKED, is turning the GPWS/TAWS off part of your shutdown SOP? Because it hasn't been on any of my equipment.

Perhaps rather than failing to read posts before ridiculing them, you could draw on your years of experience and tell me if that's normal, particularly in light of the fact that the plane ended up on the side of a mountain. It's an honest question; I'm certainly no Sukhoi driver.

edit: The file name of the picture includes the string 20120509, which of course suggests it was taken the day of the crash. And after a quick review of my old books, I indeed can't find a reason to actually change the position of the GPWS/TAWS switch on those aircraft unless it's broken or there's some reason you don't want to hear it - not as part of a normal shutdown/startup procedure. Again, there's no guarantee that carries over to Sukhoi procedures.

Last edited by thepotato232; 10th May 2012 at 12:04.
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Old 10th May 2012, 11:43
  #148 (permalink)  
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Cockpit switchology not that automated?

I flew the A319/320 for five years and when I first saw one of the Sukhoi cockpit pictures - front panel displays, sidestick etc I was struck at how similar the planes cockpit ergonomics look. Then I looked closely at the overhead panel switchery (?) and I am surprised at how manual many of the systems seem to be - needing four battery switches etc. Seemed on close inspection to be a bit of a throwback on the Sukhoi for systems that on the A320 barely need looking at/attending to. Anyone familiar with the Sukhoi systems versus Airbus? As advanced? Not so? Cheers -

Dreadful business for sure.
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Old 10th May 2012, 12:07
  #149 (permalink)  
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I am surprised at how manual many of the systems seem to be - needing four battery switches etc.
Not that unusual, the A310/A300-600 has three battery switches (because it has three batteries). Maybe this a/c has 4 and each one can be individually switched for MEL relief etc
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Old 10th May 2012, 13:05
  #150 (permalink)  
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The 3 swiches top RHS of panel, marked ON OFF, is this real, on a brand new aircraft ?.

Same swiches for sale here, just over $3 each.

Toggle Switch 20A 20 Amp 125VAC Heavy Duty On-Off: In Stock Buy Now | West Florida Components

I bought similar swiches recently for £1 each in UK, for use on a model railway. Instantly recogniseable, hence this post.

I would expect top grade electrical switchgear to be used on a brand new multi $million aircraft.

A very sad event. The above has certainly nothing to do with it, but I think warrants attention.

Last edited by flying lid; 10th May 2012 at 13:19.
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Old 10th May 2012, 13:18
  #151 (permalink)  
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@Flying Lid, maybe it's a similar perspective question to the half-full glass of water. Maybe you got yourself a good deal for your model railroad switches.

—Then again, how well do the switches work for your railroad?

I agree with your sense of irony, however. But, culturally, we do have trouble living up to the KISS ethic. Our culture likes smooth and new; but our culture is not necessarily sane.
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Old 10th May 2012, 13:18
  #152 (permalink)  
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Probably for a retrofit feature or maybe a temporary installation for test equipment?
I doubt those will be seen on production aircraft.
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Old 10th May 2012, 13:21
  #153 (permalink)  
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On the aviation herald link it says: "The coordinator of the rescue operation said, that the aircraft appeared relatively intact from the air however has received substantial damage after leaving a trail away from the crater down the slope". It seems that the impact (?) image only shows a small part of the puzzle as we did not see the plane yet, if the report is correct.
Crash: Sukhoi SU95 over Indonesia on May 9th 2012, aircraft impacted mountain
(SLF speaking)
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Old 10th May 2012, 13:21
  #154 (permalink)  
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Same manufacturer probably attaches an appropriate piece of paper to the switch and sells it for $50 as 'aviation grade' ;-)

But more interesting though - the sign above the switch reads 'SDU mode' where SDU stands for: Sistema Distancionnogo Upravleniya – fly by wire control system.

Presumably this aircraft must have been some kind of prototype version with the ability to change the FBW mode.
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Old 10th May 2012, 13:26
  #155 (permalink)  
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I was just about to post the same thing - the FBW system is something where I would not have fooled around with dodgy switches
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Old 10th May 2012, 13:38
  #156 (permalink)  
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I think people are reading too much into the overhead panel picture. The plane is clearly on the ground with the engines off. Unless the overhead panel design philosophy is 100% at odds with every other recent design, (possible...it's Russian! ) the TAWS switchlights being pushed IN would seem to indicate they are selected to their normal position, ON. This appears to be the logic on the rest of the panel. The OFF light simply means the TAWS system was not operating that that particular moment, irrespective of switch position. Similarly, note the L & R Pack and Gen switchlights. They are all pushed in for normal position, ie ON, but have OFF lights illuminated due to lack of bleed air source and generator output w/ engines shut down, respectively.

So I don't think TAWS was *selected* off in that photo. Whether the OFF light represents an abnormal condition on the ground on external power, I have no idea. It's possible that TAWS is inhibited with weight on wheels, or the FMS/GPS was turned off at the time. It's also possible that there was no database for Indonesia installed or even that TAWS was inop on the demonstrator. Point is, it's impossible to tell from that photo. I suspect we'll know the answer very shortly as Sukhoi is no doubt very anxious to clear the air.

Edit - didn't realize this was my first post . Hi, I'm Sam. E170/190 CA in the US. Long time lurker, first time poster.
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Old 10th May 2012, 14:06
  #157 (permalink)  
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That's a very good point, JungleBus. My first assumption was that the buttons don't actually stay stuck out or pushed in, just white = selected. I personally can't tell the difference between the physical position of that button and any of the others that indicate "OFF". Of course, it's also odd to me that the ground power is in use but all of the batteries are switched are off, but as I've said, I really don't know the first thing about this plane. It's just that with the exception of the batteries and the one TAWS light, everything else looks set up exactly as I'd expect for an airplane under ground power that isn't ready for start yet. I would think the FAULT lights are a perfectly normal indication if the system isn't up yet, just scratching my head about the OFF one. Also wouldn't have a clue why the SYS button wouldn't be OFF too if it's related to inhibit logic, but as I said, not my airplane.

I'm a few years removed from the 170/190 series, and now I'm trying to remember if the white indications for buttons on that panel are for selected positions, or if they're more general than that. I know amber = isn't working right, I just don't quite remember the switch logic for white. The overhead panel on the Sukhoi just looks so much like an Airbus, that's what I defaulted to in my head.

Good first post, JB. Thanks for the added perspective!

Last edited by thepotato232; 10th May 2012 at 14:19.
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Old 10th May 2012, 14:19
  #158 (permalink)  
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On 737 it is normal when leaving the aircraft unattended to have Batt Sw off & Gnd Pwr in use. Then, when the GP is disconnected (or becomes accidentally disconnected) no need to do anything to avoid arriving in the morning to find a flat Batt.

Anyway,forget all this switchology discussion, all said & done, TAWS is there to save you if all the rest goes wrong, not to enable/facilitate you fooling around below MSA in the mountains in [email protected] wx.

Without wishing to prejudge, I think the cause is going to be a whole lot simpler than anything technology based.
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Old 10th May 2012, 14:24
  #159 (permalink)  
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The debris pattern in the the hillside is consistent with an impact like this (F-4 into a concrete barrier)

I was trying to explain to some non aviation people today that the hope of finding victims remains intact after a high speed collision with a solid object are remote.

The forces involved in an almost instantaneous stop from cruise speed are tremendous, most people can't comprehend that.
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Old 10th May 2012, 14:29
  #160 (permalink)  
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Oh yeah, duh. I guess that would be perfectly normal for the battery under those circumstances. That just leaves the one light that's got me wondering.

And I agree with you 100% about TAWS being more of a failsafe than a license to be reckless. I'm just wondering if that button showing OFF is a normal indication on this a/c, or it's indicating that way because the pilots had it switched off for some reason or another. It's certainly too early to try and throw either the pilots or anyone else under the bus, I'm just looking at something that doesn't quite add up with my own meager experience.
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