Rescuing Dr. Maciej Lasek & His Crash Investigations Team An aircraft wing can suffer catastrophic failure without ever being registered by the “Black Boxes”.
Dr. Maciej Lasek - PHOTO by REUTERS
Usually, Dr. Lask’s Smolensk crash-related Tweets do not require lengthy commentary, but this time, I will make an exception.
After release of the simulation representing the most likely sequence of events during the final phase of the tragic flight to Smolensk, presented by the Parliamentary Committee, Dr. Lasek tweeted a hint that he needs some help. Because he was unable to respond precisely as to what particular changes of the flight parameters would have been registered in the event of the explosions in the wing, I decided to be a good Samaritan, and to help this government body by sharing my thoughts on this subject; at least as much and as effectively as I can.
Before I help Dr. Lasek, as I have promised, I have to briefly explain something. The simulation presented by the Parliamentary Committee differs in several key areas from my own observations. It does however, depict the sequence of explosions, which in my opinion, is the most likely scenario. This fact, it appears, is a substantial hindrance for Mr. Lasek. So, for exactly these reasons, I am landing my helping hand.
[Mr. Lasek] who leads the [official Polish government Crash Investigations' Committee] tasked with explaining the Miller’s Report to the uninitiated, responded sarcastically to the depiction of the sequence of explosions presented in the [Antoni Macierewicz] Parliamentary Committee [simulation], and wrote:
… As I understand it, not all ‘explosions’ were registered [by the black boxes] – their synchronization with data recorders is surprising.
It is difficult not to agree with Dr. Lasek. He understood it correctly. None of the explosions were registered directly. But, it is not surprising. To the contrary, it is typical for the TU-154M aircraft. After all, as someone who chairs this official [Polish] government body, and whose work is funded by the [Polish] taxpayers, he should know better.
The TU-154M black boxes register the state of some of the wing elements among other data. If the flight data is analyzed, certain system-failures, to which the aircraft’s wings could have possibly been subjected to, can be ascertained, indeed, but not all of them, unfortunately . There are fewer sensors in the left wing that are connected to the sensor recorder, than in the right wing. This fact should help to dispel Dr. Lasek’s doubts at least in some part. The “Black Boxes” do not register either the condition of the left wing slats (even though appropriate sensors are present in both wings, the data recording originates only from the right wing), nor the condition of the left aileron. It means, that progressive and substantial damage to the wing - causing uncontrolled rotation and an inevitable crash for a plane– is possible, but it will not in any way be registered by the “black boxes”. Under one condition, however: the damage has to be sustained by the left wing, and not the right one. This is exactly what happened in Smolensk.
[Polish Government] investigators, who (according to numerous public statements made by the members of the Miller’s Commission), limited their activities to the analysis of the"black boxes", basically had to overlook the symptoms of destruction of certain areas of the left wing. It must have happen if only the front and middle parts were considered, and that the damage was quick enough. The center of the wing could be subjected to substantial damage long before the aircraft was to reach the runway. [Dr. Lasek’s] researchers, with a sense of a job well done, can then continue to convince the public opinion that the plane was undamaged before it "hit the famous ‘armored’ birch".
Let us see, if we can reconstruct particular chain of catastrofic failure events sustained by this aircraft, the ones matching the data captured by the Polish ATM QAR “black box” on the one hand, and confirming multiple explosions during the flight, on the other. I hope that the readers will forgive me, because for the illustration’s sake, I’ll show Dr. Lasek how my findings, and not those of the Parliamentary Group’s, reflect the data captured by the “black boxes”. The choice is obvious, as I am most familiar with them. Let us assume, that the aircraft leaves for go-around at big pitch angle (approximately 13 degrees), and its outer wing fuel tanks are almost empty – as KBWLLP ascertained in its report.
The first failure takes place around the inner marker area: it is a small point explosion in front of the left wing, in front of the first spar. It destroys a spar and leading edge (wing’s nose) partially, and partly cracks small area of the slats. As a result, the wing will start to break, twist, lose lift force and cause braking on the left side of the plane, but the process needs to take a few seconds.
1-initial explosion in front of the front spar. Part of the slat is broken, spar is damaged.
What does the investigator see loking at the ATM QAR recordings? Electrical system 36 V does not sustain any damage (because it will not be damaged even later, by a hypothetical colission with the birch). See: "Separation of 1/3 of the left wing could not be caused by the impact with the birch tree. Most probably separation of a fragment of the left wing was caused by explosion in the air." by Dr. Wieslaw Binienda, Ph.D., Dublin Institute of Technology. Similarly, the electrical system 27 V will also remain undamaged. The Miller’s Commision had to presume it was damaged by looking at broken cables and broken navigation lights on the wingtip. The 27 V voltage did not drop even past the Dr. Bodin’s birch. The hydraulic systems “1-3” are functioning properly. Even the later separation of the wing tip will not cause any significant fuel leaks. The Miller’s Commision wrote it in their report.
Although slats were partially broken off, the investigator does not know it, because their state is not recorded at this side of the plane, and the damage they sustained is relatively small. The goal of the explosion was to weaken the spar, and not blast off all the slats, as their total destruction would be difficult to explain. The explosion is so small itself, that the breakdown of lift force is not felt, and has no effect on the acceleration of the center of gravity of the airplane. The drag (resistance) of the left side increases so slightly, that the plane does not begin to change the direction of the flight yet. This explosion has no effect on the behavior of interceptors and spoiler, which are mounted on the back of the third (the rear) spar. Their condition is normal. There is nothing alarming about the fuel level registered by the "black box". The aircraft flies with a raised nose; the remaining fuel in the wing floated into the rear part of the fuel tank, and even if the front tank was punctured, the diameter [of this puncture] is small and is located at the top. Besides, "black box" shows something disturbing only when the fuel level falls by more than 200 kg. For the time being the aircraft is still safe. What does an investigator of "black boxes" see? Nothing. The aircraft is fully operational.
The second failure takes place before the Bodin’s plot. This time, this is much larger explosion, and already in the front caisson, now an empty tank filled up with fuel vapors. The explosion is placed between the first and second spar in the mid-section of the wing. Large part of the slats falls off. The upper part of the front caisson breaks into narrow, but long pieces, the lower sheathing (skin) is partially torn and bent, and starts generating an extra drag. Spars number 1 and number 2 (the front and middle ones, respectively) are already damaged and partially broken. The ribs are completely destroyed throughout a large area. But, the recorder is not capturing the condition of those parts of the aircraft at all. After the explosion, the front of the fuel tank is blown from up on the bottom. The shock of the explosion is felt even in the hull. What does the "black boxes" investigator see?
1- Possible sparking of electrical wiring, 2- Electrical engine of fuel pump, 3- Big part of lower skin, partially torn from the spar and ribs, creating extra drag, 4- Front spar, 5- Hot gases get into the neighboring fuel tank, 6- Part of slat, thrown away from the wing
There is decrease in the acceleration. But, an “armored” birch tree is growing somewhere around this location. There are no anomalies in the functioning of electrical and hydraulic systems. There are no fuel leaks (aircraft flies with its nose up, so the fuel is still being transferred to the rear of the tank). The rear caisson has not yet been damaged, the rear wing interceptors are fine, the spolier shook slightly. "They probably hit the birch" - concludes the researcher. And if they hit it, both fuel tanks must have been cut. The investigator knows that at this moment the plane slightly tilted to the left. But, he will not investigate what the fuel level was, nor why several hundred kilograms of jet fuel didn’t spill. He will not investigate, because why shoud he? The fact is, that the fuel didn’t spill after the wing was completely sheered by the “armored” tree. Never mind. Is it possible that the researcher overlooked the fact that the latter part of the rear caisson with fuel is still intact, that it will remain unscated at least until reaching the Gubenko street, at which point the tilt to the left will increase to more than 15 degrees?
Meanwhile, the aircraft with a completely destroyed front of the middle of the wing, and increasingly vibrating, damaged wingtip begins to turn to the left violently. The extent of destruction of left wing, causing such rapid rotation would be determined only computationally or experimentally. No, it is not necessary. "As it hit it, it was broken” - thinks the investigator. Because the state of the left aileron is not preserved and recorded, a researcher can not determine whether the wing tip already dropped out or not. In this location the ATM QAR recorder begins to have problems with saving data. From this point, the researcher will not retrieve any trustful data form the Polish “Black box” – particular data will have to be reconstructed, and invite errors that may occur.
The third failure event, took place few dozen meters before TAWS38. See: Smolensk Plane Crash: Four Years Later, Kazimierz Nowaczyk, Ph.D., IWP Presentation. Electrical systems begin to generate sparks, and there is a secondary explosion of the fuel-air mixture in the rear part of the wing tank. The rear spar is damaged in the area of the spoiler; although interceptors, which are located closer to the fuselage, do not show any signs of failure, and do not open. Tremors are felt even in the center of gravity of the aircraft, and are recorded by recorder as the violent acceleration breakdown, but the researcher can interpret them as hitting trees. How is he to know that anything exploded in the wing?
1- Left spoiler, 2- Electrical wiring placed behind the rear spar, 3- Fuel-air explosion in rear caisson, 4- Pressure wave gets into the neighboring fuel tank, 5- Additional damages to the front spar, ribs and sheathing
Along with the third spar breaking into pieces, the spoiler suddenly opens. Then, it falls off, returing "zero" readout until the end of the recording. The researcher can only presume that with the opening of a spoiler, the tip of the wing fell off. Direct evidence does not, and will never exist, because the state of the left aileron is not ever recorded at all. One can only dream about the assessment of the condition of slats, that could indirectly help in inferring the approximate location of the destroyed surface of the wing - this information isn’t recorded, either. Anyway, why should it be checked if the researcher knows precisely that after losing 4.5 meters form the wing tip, an aircraft weighting 80-tons must turn upside down?
If failures described above took place on the right wing, one could determine with a high degree of accuracy when and where the aileron, maybe even the slats, were damaged, and when the tip of the wing fell off. But it was impossible to find out all the left wing damage areas only by examination of the "black boxes" themselves. By a strange coincidence, it was the left wing that was destroyed. So, the investigators did not notice a thing …
Let us give voice to Dr. Lasek, who says the following about the last explosion before the debris field:
In this [Tu-154M] aircraft, the cabin pressure is equalized with atmospheric pressure before landing. But, the hull rupture would leave traces on recorder (differential pressure measurement) through the influence of the air flowing on the static pressure inside the hull .
It seems that Mr Chairman [Dr. Lasek] did not consult with Dr. Lipiec, who was expert on flight recorders in the Miller’s Commission, before writing this. A pity. Because, the cabin pressure is recorded at an interval of every half a second.
If an explosion lasting about 1/1000 of a second occurred in the hull during the interval between these recordings, and at the same time the explosion disabled electricity supply to the "black box", then there will be no traces of pressure increase in the captured data. The investigator will be investigating, and he will discover nothing …
By Marek Dabrowski
The author’s complete analysis of Smolensk crash events (in Polish) can be found here.
Marek Dabrowski holds Masters of Science degree, and is an independent analyst and author of publications in the field of military technology. He also authored the papers concerning the Smolensk crash which were presented during the First and the Second Smolensk Conferences in Warsaw, Poland.
"Russian Image Management"
The trip to Smolensk was expected to highlight Russia finally admitting culpability in the massacre, after long having blamed it on the Germans, an atrocity they had tried to conceal for over 70 years.
As for the reception committee, it had different ideas. Putin wasn’t looking forward to such an occasion. Into this poisonous reception brew was President Kaczynski’s well-known public criticism of Moscow and Putin, a habit that has ended the lives of others within Russia – and abroad. A few discouraging Russian requirements – that Kaczynski could not attend in any official capacity – did not halt the Poles. Kaczynski would go anyway on non-official, “personal” business. To Russians, such a distinction would be meaningless, not lessening the possible international excoriation of such an event. A problem ripe for a modern, Russian solution: a tragic, ‘natural’ accident.
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