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Polish Government Tu154M crash

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Polish Government Tu154M crash

Old 27th Apr 2010, 11:22
  #981 (permalink)  
 
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Tonden,

let's hope, this time they'll keep the promise and publish something tomorrow.

Keep the fingers crossed.
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Old 27th Apr 2010, 11:36
  #982 (permalink)  
 
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Crash site, plane parts marked

Sergey Amelin (the author of many pictures and shemes posted in Smolensk forum) today posted crash site satelite picture with marked majour plane parts.
As hi is writing - initial version, some innacuracies are possible.

Currently the tail part (red with ? mark) is indentified as laying in another place.

http://s48.radikal.ru/i120/1004/3a/5b58462f20d6.jpg

Corrected sheme is here: http://s41.radikal.ru/i091/1004/44/5dcbe16522b5.jpg
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Old 27th Apr 2010, 11:57
  #983 (permalink)  
 
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Conspiracy Theories

Most of the discussion between professionals here ends up with statements, "We don't really know the answers, we have to wait for the conclusions of the official investigation - but - we ask questions in the meantime to sort and clarify all possible causes of this tragic accident. This means that you, at least for now, are formulating hypothesis, not theories.

In that sense, there are no wrong questions, although there may be many wrong answers. This is what inquiry is all about.

Let me point out to you that 99% of all discoveries and inventions started with asking questions to which we didn't know the answers. One could say that we owe all our knowledge to "educated guesses" or to "conspiracy theories".

Having said that, if you knew history and understood our reality better than just being trained in a narrow field of flying airplanes (no matter how "professional"), you would know that possibile causes of this accident are much wider than technical failure of the equipment, a pilot error, or a "mess" in Russia's procedures. They also include a huge and very real area of politics. There are many historical facts that support this view and excluding this area of inquiry in this particular case proves that you are not being objective. Or perhaps, it is just an excuse to be politically correct? But remember, once you start down this path, you compromise your chance to find true answers to your questions.

Respectfully,
Bielec
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Old 27th Apr 2010, 12:02
  #984 (permalink)  
 
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Bielec,

as a first tool of any investigation, I suggest Occam's Razor.



For those unfamiliar:

Occam's razor (or Ockham's razor), is the meta-theoretical principle that "entities should not be multiplied beyond what is necessary" (entia non sunt multiplicanda praeter necessitatem) and the conclusion there of, that the simplest solution is usually the correct one.

Occam's razor - Wikipedia, the free encyclopedia
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Old 27th Apr 2010, 12:14
  #985 (permalink)  
 
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To BOAC

Originally Posted by BOAC
From around 16 April - whenabouts PJ2 lost interest - we have been bombarded with bizarre comments, including baddies shooting at mutilated corpses, conspiracy over the time of the crash etc etc.
I think most of us who have flown professionally actually have a pretty good idea what happened here.
Be sure that your opinions are appreciated.
As it was mentioned by Ptkay, we try to deliver/translate the "a.m. data" from the available Polish/Russian sources to learn an independent judgment. There is a huge political tension now in Poland (the catastrophe, the subsequent presidential election, etc.) and the unbiased guesses/statements/observations are wanted badly.

PS
Originally Posted by Ptkay
Bielec,
as a first tool of any investigation, I suggest Occam's Razor.
A priori (before one learns the facts) one should rather follow the Pascal law..
to assume a uniform distribution [of hypotheses] in the absence of reasons to the contrary

Last edited by Bahrd; 27th Apr 2010 at 12:46. Reason: To Ptkay
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Old 27th Apr 2010, 12:34
  #986 (permalink)  
 
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Bielec,
a small correction. The people familiar with accident investigation/analysis do not actually "have to wait for the conclusions of the official investigation", just some more actual facts.
Derived from data such as flight recorders, ATC/CVR transcripts, captured readings from the flight instruments etc.

I don't think it has even been confirmed yet what type of approach the aircraft was carrying out. (A twin NDB approach seems to be a likely candidate.)

So the questions of, shall we say, a political nature, tend to be promoted by some in the absence of hard data.

Folk who work in the operational side of aviation are usually a fairly pragmatic lot, and prefer to wait until some facts are in.
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Old 27th Apr 2010, 12:42
  #987 (permalink)  
 
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I agree

Then, the only problem is to decide what is "necessary". And that is where people disagree.

Anyway, I don't want to take space and time on this forum to divert your topics to "unwanted" area. I respect your right to select and protect your discussions according to your intrests and your area of expertise. (Did I say it right?)

However, I have a question of a more technical nature that professionals in this forum may help me answer.

Amelin has posted some information and a couple of pictures on the structural strength of an airplane similar to TU-154 - see here:
Google Tłumacz .

It suggests that large airplanes have some sort of a solid, massive frame that runs along the fuselage. This frame is needed to provide secure connection with wings and the tail sections with the engines. It holds the whole structure together and provides safety to passangers and crew (for example, seats may be securely fastened to the frame through the floor).

If this is true, the "frame" itself must be a rather large and sturdy part of the structure.

Ami then explains that in the TU-154 accident, the entire front of the plane disintegrated. As the A/C was inverted during the impact, the roof and sides of the fuselage were practically stripped off and torn into small pieces. This explains why there is no fuselage on the pictures from the crash scene. But, there should be a frame or at least large fragments of it. I tried to find anything that would resemble such a frame or parts of it in the pictures and videos available but could not find anything.

My questions are:

1. Is there a solid frame (sort of a spinal cord) in a TU-154?

2. If yest, could it just desintegrate and disappear during an accident like this?

3. Or, am I missing something in the pictures and videos that are online?

See the video here:
Sk?adaj? Tupolewa ze szcz?tkw. Zobacz unikatowe zdj?cia - Polska - Informacje - portal TVN24.pl - 16.04.2010

showing all the parts being prepared for re-assembly.

Bielec
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Old 27th Apr 2010, 12:54
  #988 (permalink)  
 
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A few bits of new (?) information (in Polish):

Nie mo?na poda? godziny rozbicia si? prezydenckiego samolotu- Onet.pl - Wiadomo?ci -27.04.2010
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Old 27th Apr 2010, 12:56
  #989 (permalink)  
 
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@ Tarq57

So the questions of, shall we say, a political nature, tend to be promoted by some in the absence of hard data.
Not necessarily "in the absence," as technical causes and political circumstances don't really exclude each other.

For example, trying to figure out wheather or not the pilot acted under pressure to land is at this stage a pure conspiracy theory, and yet, some people here feel that it is appropriate to discuss this aspect of the case. That's what I mean.

But I take your point, too. Yes, there are some who turn to conspiracy theories out of lack of more educated ideas. But not all.

Bielec
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Old 27th Apr 2010, 12:57
  #990 (permalink)  
 
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how it could be cont.

posts from Sergey Amielin blog made by Tomasz tu154 pilot
"I have confirmed information that the pilots of Tu-154 and their colleagues from the 36th Special Transport Aviation Regiment routinely used the non-WGS-84/PZ-90.02-compliant coordinates (runway threshold) given on the Smolensk instrument approach charts. They should not if the FMS was set to WGS-84. Evidently their training was lacking in that area."
"The error estimated was 180 m east-west and 30-40 m north-south. That explains why the aircraft was 40 m south of runway's extended centerline - it was pefectly tracking runway's extended centerline to the runway threshold. The crew had the distance from the threshold - the indicated distance ws 180 m shorter than the real one - but it is irrelevant to the crash - this position error is not significant enough "
"One should not expect better guaranted accuracy than 550 m (0.3 NM) with GPS RAIM anyway. Unfortunately their vertical navigation was much less perfect."
"I have made an analysis of possible Tu-154 approach profiles with use of available flight simulator and I am now leaning towards the third primary reason, not mentioned by me before - barometric altimeter setting error. I don't know who made the error - controller or pilots, if this theory is right. Simple entering QFE value 759 mm Hg instead of 749 mm Hg would put the aircraft 120 m lower than intended by the crew."
"It seems to me a bit less likely now, that the crew intentionally doubled the rate of descent, being as close to the ground as 100 m above aerodrome threshold, because it seems to be contrary to common sense of majority of airmen. Possibly, they could have believed, according to the baro-altimeters (with wrong QFE) that they were high on the glidepath (virtual, since no glideslope existed) and close to the Inner NDB."
"That's why they increased rate of descent trying to reach MDH shortly before Inner NDB or over it. Unfortunately the RA altitude callouts could have been unavailable, due to TAWS inhibition by the crew (depending on type of TAWS) caused by lack of XUBS airbase in TAWS airport database - possibly they never included scan of the RA - maybe it was intented later, after passing Inner NDB, as I previously noted, providing they had ever considered going below MDA. Maybe they never intended to go below MDH."
"On the other hand you don't try approach with 400 m visibility and 120 m MDH. The success, even without considering the tragic approach lights technical condition, was unlikely, without ducking under MDA close to the Mised Approach Point. Maybe they had reason to believe that the visibility had been better than reported. Or maybe they just wanted to close the mouth of their supervisors ungry that they didn't give a try. Definitely there was lot of pressure (even if not spoken verbally)."
"Staying high on glidepath could be misleading to the controller, who was not aware of wrong altimeter setting or anything else going bad, until they increased the rate of descent. Increasing rate of descent at about 2 km from the threshold, when you know you are in heavy jet just 100 m above the ground is a bit strange to me - however if they wanted to try really hard and had never thought about the lower terrain 1.5 km from the threshold"
"(I bet they were not aware of its existance - you don't see such insignificant things during approach in VMC), they just had concentrated on RA and artificial horizon and pressed on, however the pilot monitoring should be looking occasionally outside. Likely he saw the ground just two or three seconds too late."
"Regarding the wrong QFE the question is whether the error was made by the controller or by the crew, and exact circumstances of the error making. And no doubt, it always unsafe when you mix QFE with QNH, mm of HG with of hPa, and meters with feet, especially if you are accustomed to QNH, hPa and feet, because it always adds some unneccessary confusion and distraction."
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Old 27th Apr 2010, 13:09
  #991 (permalink)  
 
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No frame?

Given the forces involved, there must be something solid and sturdy to connect all the parts of the A/C. Ami was explaining it in Part 4. Looking at al available pictures and videos, I cannot find anything that would resemble a "main frame" structure. Even on this video.

I can understand why the top and the sides of a fuselage would be stripped and torn to pieces during an inverted impact. But a solid frame could not just desintegrate, could it?

Bielec
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Old 27th Apr 2010, 13:14
  #992 (permalink)  
 
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I hope that our professional colleagues here will accept that the above is
also a professional pilot opinion, just translated and reposted by an
unprofessional layman, although with good command of Russian language.
(Uphill, no offence I just don't know you.)
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Old 27th Apr 2010, 13:26
  #993 (permalink)  
 
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Ptkay,
Yes, absolutely. That comes from someone who knows what they're talking about, FWIW from me.
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Old 27th Apr 2010, 13:40
  #994 (permalink)  
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Uphill's post is the best we have seen for days, but the hypothesis is easily sorted by the settings on the instruments, which will be known now. They will confirm or trash the QNH/QFE/mis-setting issue. There is little point in surmising.

Back to the conspiracy theories - I'd like someone to be brave enough to say exactly what the 'theory' is behind all the stuff about gunshots/incorrect crash timing etc with which we have been entertained recently.

I may have missed it in all the froth, but have we ever seen a confirmed RVR and DA/H for this approach here? Is it actually 120/400?

Bahrd - I fully understand your comments on the 'tensions' etc, but I wonder how a reasonable 'independent judgement' can be arrived at? By the way, like Ptkay, I favour Occam
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Old 27th Apr 2010, 13:49
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BOAC, what's your point now? Posts advocating conspiracy theoires that appeared a few nights ago were deleted, so at the moment we have more complaints about them than actual posts about them. It's not helpful either.
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Old 27th Apr 2010, 13:56
  #996 (permalink)  
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OK, criss - probably not surprising, but I had not bothered to look back at them and didn't actually expect that to happen - bravo! In which case apologies to all and on we go. You never know, we may even get PJ2 back.
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Old 27th Apr 2010, 15:36
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BOAC

I was one of the "regulars" who at first tried to rebutt the conspiracy poster(s) with facts. I should probably have done as PJ and realised they wouldnt stop -- as they basicially hijacked the thread. I then complained quite strongly to the mods, as did others I'm sure, and eventually all was cleaned up.

For whatever bizarre reason, I saved some of the more ludicrous postings. I'll pm them to you if you really want to see them (but I would advise donning your tinfoil hat prior to reading ).

grizz

Last edited by grizzled; 27th Apr 2010 at 17:21.
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Old 27th Apr 2010, 15:52
  #998 (permalink)  
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I'll pm them to you if you really want to see them
- err thanks but no thanks
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Old 27th Apr 2010, 21:22
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No frame.

Bielec,

There's no frame in the fuselage. It's a semi-monocoque, fail-safe structure -- however there are some reinforcing elements (stringers and stations), it's the skin what bears significant part of the loads. (see Fuselage - Wikipedia, the free encyclopedia, nice picture of the 747 fuselage structure: http://upload.wikimedia.org/wikipedi...selage-747.jpg). Fail-safe means that the structure is somewhat redundant and can retain required properties (stiffness etc.) even in case of partial failure, like in case of the Aloha B737 mentioned by Amelin.

However in crashes like that in Smolensk such a structure behaves like an egg's shell (in fact an egg's shell is exactly a monocoque structure).

Regards,
Mike
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Old 27th Apr 2010, 21:46
  #1000 (permalink)  
 
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Originally Posted by BOAC
Bahrd - I fully understand your comments on the 'tensions' etc, but I wonder how a reasonable 'independent judgement' can be arrived at?
I hope we will learn the investigation data soon.
There are, in fact, two investigation boards (in Poland and in Russia), however:
Originally Posted by Thomas Bradwardine
Like the intertwined triple line is difficult to break, so the conclusion, demonstrated in three ways, will not be easy to overthrow.
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