Without the black boxes we will not explain this crash.
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The Interstate Aviation Committee (IAC), investigating the crash of 10 April, previously accredited the Samara aviation plant, which had serviced the Polish Tu-154M.
The Russian committee’s evasion and exclusion of the possibility of damage, may be perceived as its defensive reflex.
Without revealing the original contents of the black boxes, explaining the reasons of the presidential plane Tu-154M is unrealistic, experienced pilots claim. They also stress that the fragmented information relayed by the Interstate Aviation Committee is not grounded on any evidence. In this situation it is difficult to estimate to what extent the provided details agree with the facts, especially that the committee rejects certain hypotheses without giving reasons.
One can conclude from IAC’s work so far that the Russian commission is inclined to blame the crew of the presidential plane for the crash that happened near Katyn. However, its circumstances still generate many questions. Although the committee has provided a handful of details (of little importance), it has not brought the public any closer to truth about April 10, 2010. For instance, we do not know why the autopilot led the plane just above the ground one kilometer before the runway. If the crew had been acting correctly, the height over the far beacon should have been set on the device, the speed of vertical fall to the near beacon and – depending on those parameters – the height over the near beacon. Theoretically, it can be assumed that only the value of the vertical fall was set on the autopilot, and it may have been an incorrect one… This data should have been read from the black boxes and well known to IAC. The commission, however, does not give any details in order to justify its hypothesis about the crew’s error and poor training. Why? All we know is that the TAWS system had been warning the pilots about approaching the ground and the pilots did not react instantly. Here as well, IAC does not explain the reasons and what had been going on aboard then. Following the rhetorics of the commission, one could think of the Casa-295M accident in Mirosławiec and assume that the pilots were convinced they had descended below the decision altitude (that is why they ignored the TAWS warning signal) and were both focused on looking for the ground (which would have been impermissible). Flying in fog and not observing the devices, they had a difficulty with estimating the plane’s position… The previous findings by IAC do not confirm this in any way. What is more, other doubts arise as to credibility of such a thesis. We still know that the autopilot had been switched off 5.4 seconds before the plane struck the first obstacle. According to experienced pilots, at that moment the plane must still have been a dozen or so meters over the ground, so the pilots had the time to pull it up and fly higher. They did not, however. 5 seconds is enough to fly up. This kind of a plane can make it higher even after 1.5 seconds and it would have been sufficient if the pilots had gone into vertical flight, claims an experienced pilot of Tu-154 (name known to the editorial staff).
Here the question of the plane’s damage comes out again – did the machine fail to fly up because of engine failure or because it had become uncontrollable?
The doubts are increased by the fact that IAC, which is investigating the crash, accredited the Samara aviation plant, which had overhauled the Polish Tu-154M. The evasion and immediate exclusion of the damage hypothesis, without presenting the recordings from the black boxes, may be perceived as a defensive reflex of the Russian committee.
We are waiting for original and complete recordings
According to experienced pilots, it seems doubtful that incorrect data had been entered into the autopilot. As they told “Nasz Dziennik” (“Our Daily”), it was unusual and too fast for a Tu-154M to have descended from 200 m to 100 m. 18 seconds before the tragedy the pilots heard the warning “pull up”. They should have switched off the autopilot immediately. Why did they not do it if the plane was operational? Or maybe the machine was malfunctioning? Why did they wait for so long? It is a puzzle for me because nobody behaves like that, claimed one pilot. In his opinion, the plane should not have been in that place and on that altitude and it is still unclear why it happened. As he added, this situation makes it important for the Polish side to hear the contents of the black boxes and read the flight parameters, engines’ operation, temperature of the exhaust gases, listen to what was happening in the cockpit and find out why the crew were not replying to the air traffic controller.
Doctor of Engineering Ryszard Drozdowicz, who is also a pilot and specialist of aerodynamics, sees the catastrophe in a similar way. In his view, without full information about the contents of the black boxes it is impossible to understand what happened on April 10. “The first thing to point out is the source of information, which does not directly come from the original recording of the black boxes. It must be strongly stressed that only the original recording has informative value and can the basis of the investigation. The pieces of information reaching me so far come from indirect sources and do not fit together in any way”. Referring to the use of the autopilot by the crew of the governmental plane, he emphasized that he did not understand why experienced pilots flying such an important delegation should need the autopilot on the descent path, a few seconds before landing. As he remarked, the reason for two well trained and experienced pilots aboard is to perform the maneuver manually – the instruments are only used by them to control the landing.
Let’s remember that safe landing is, and has always been, the most difficult. I cannot imagine allowing this phase of the flight to be performed even by the most advanced autopilot, and with such passengers on board, he added.
ILS or RSL?
It is possible to land a plane using the autopilot thanks to the Instrument Landing System (ILS), which helps in landing in difficult conditions and with limited visibility (the autopilot can steer the plane along the descent path and direction, and make corrections itself).
In this way the plane can be automatically brought onto the runway and the pilot usually takes over the control just before the touchdown in order to keep the plane on the runway when the wheels touch the ground – at this moment the pilot is able to correct the machine’s course. Landing with the autopilot is also possible without ILS. In such a case the pilots, using the autopilot, follow a determined route – they set the vertical descent speed on the variometer and the plane approaches the ground at the set value (usually 3.5-3 m/s). The vertical descent speed is maintained by the autopilot. That is probably how the Tu-154M was flying. In this particular case, however, other warning instruments should have been switched on, such as TAWS (with a correctly set decision altitude). Moreover, the radio altimeter should have been operating from 1500 meters. If the decision altitude has been set on the device, it should loudly alarm the crew when they have dropped below it. This altitude depends on an airport’s parameters. When landing is performed with 2 NDB’s, the standard value is 200 meters over the far beacon and – if the autopilot descent is not interrupted – the plane will continue dropping until it reaches the level of 70 meters over the near beacon. These are the standard values which may differ depending on the characteristics of a given airport and the location of the NDB’s, Ignacy Goliński, former member of the State Commission of Aircraft Accident Investigation, explained. He noticed that apart from certain media reports, no official information has been given about the landing system used at the Smolensk airport, whether it uses two or one NDB (the latter can also be occasionally found), whether it is based on ILS or the radio-location landing system? That is important because it determines the altitude values mentioned before and the way in which the plane is brought to the earth, Goliński added.