Il-112V: the causes of the disaster have been established
In the previous article, in fact, the opinion was expressed that the main reason for the Il-112V disaster in Kubinka was the haste of our Ministry of Defense, who passionately wanted to show the car at MAKS and Army-2021.
Actually, nothing has changed, but now there is an expert opinion on the causes of the plane crash. I must say that the conclusion does not answer all the questions, on the contrary, it adds new ones.
Having deciphered the data of the aircraft flight recorders, the experts came to a very unpleasant conclusion: the fire that began in the right engine led to the ignition of the skin and internal structures of the wing, but the transition of the machine to an uncontrollable lateral roll and overturning of the machine caused the destruction of the aileron thrust by fire. Aileron provoked the overturning of the car and the ensuing disaster.
The on-board recording device did not record any conversations in the last seconds of the disaster. The crew of professional pilots probably understood what happened and what was the reason for the plane no longer obeying the rudders.
The pilots really could not do anything in this situation, in the car, which completely lost control in these short seconds. Therefore, the pilots died in silence, without saying a word to each other.
What happened to the plane? Crew error is excluded, and such a first-class crew could not be so wrong.
A group of experts from the Interstate Aviation Committee and their colleagues from the Ministry of Industry and Trade found that the fault was a malfunction of the aircraft's right engine and the subsequent surge. This was followed by the loss of gas-dynamic equilibrium by the engine and, probably, the destruction of the turbine. Usually, the surge destroys the turbine blades first of all, and already the debris of the blades begins to destroy everything around.
Apparently, the turbine blades broke the fuel lines, after which the fuel began to ignite. All this happened a few minutes after takeoff, the plane had just begun to climb, and a fire had already started inside the wing and in the engine nacelle, caused by kerosene spilled from the broken fuel lines.
Why the alarm did not go off right away and the fire was first noticed by the dispatchers at the aerodrome tower is not entirely clear. But the fact is that it was the dispatchers who warned the crew about the fire that began on board, and only then the alarm went off.
The crew calmly replied that the situation was clear and began to fight for the plane. The automatic fire extinguishing system was first activated and a foamy composition was fed into the engine nacelle to extinguish the fire.
The first extinguishing did not give results, the fire continued, and the pilots already manually activated the second stage of the fire extinguishing system.
But this did not give the expected effect, since the spilled fuel was already burning inside the wing. The design problem of the Il-112V: the fire fighting systems were focused on extinguishing the fire inside the engine nacelles, and were not designed at all to ignite the fuel inside the wing.
In addition, the fire extinguishing system on the Il-112V was greatly reduced: only two fire extinguishers per side. Usually in "Ilakh" the system is installed on the planes, which extinguishes fire in SIX bursts. That is, on each side, in the case of the Il-112, there would be SIX fire extinguishers instead of TWO.
What caused such a reduction in security systems is a question.
On this, the fight against the fire was over simply because there was already nothing to extinguish it. Both foam cylinders were used up and the crew decided to land the burning plane as quickly as possible in order to extinguish the fire on the ground. Actually, this is the only thing that remained in such a situation.
The crew requested an emergency landing, which was given. The recordings recorded the clear and intelligible actions of the crew. The burning engine was turned off, the propeller was feather-air, and on the remaining engines the pilots were able to turn the plane and go towards the airfield. Under these conditions, they were able to find the ideal position of the rudders and thrust of the remaining engine and the plane began sliding (according to experts), at the end of which the plane would definitely land on the runway from which it took off.
About one and a half kilometers remained to the runway ...
But the fire, which continued in the wing, did its job and the pilots failed to accomplish their plans. In some 45 seconds after the start of the fire, the aileron thrust, a duralumin tube with hinges, which held the right aileron in the lower position, lost its properties. Further, the thrust collapsed. The destruction of the thrust led to the fact that the aileron got to the neutral position and ceased to compensate for the asymmetry of the left engine.
The plane began to roll to the right and lower its nose. Further, the overturning of the aircraft began, and it crashed into the ground.
Obviously, the pilots understood what had happened. They could no longer influence the situation, so they simply silently entered the last bend of the plane.
The last bend lasted three seconds. Il-112V rolled over its right wing and fell to the ground.
The IAC experts considered that in such conditions it was simply impossible to get the plane out of the roll.
Most experts believe that the reason for the tragedy was not the readiness of the prototype aircraft for such flights and the rush caused by the desire to show it to the general public.
In fact, I don't even want to imagine what could have happened in a similar situation if it had happened not over the forests of the Kubinka-Alabino region, but over the field of the MAKS or Army-2021 exhibition. And how many victims there would have been.
The actions of the heads of the Ministry of Industry and Trade are perplexing, who, according to some media reports, set the task for the members of the commission “to find out in detail whether there were any errors by the crew during the landing approach”.
The crew did everything in their power, and is it even worth trying to put on the dead pilots at least a fraction of the responsibility for what is happening. It would be more weighty to simply ask the competent employees of VASO about how and from what this prototype was assembled.
Sorry, you can't call the Il-112V a full-fledged aircraft. This is not an airplane, this is a prototype airplane. Which was collected on the initiative and at the expense of PJSC "IL" at the plant in Voronezh.
By coincidence, the author lives in this city and has several VASO employees in his social circle. Naturally, he could not help but ask the factory workers about the IL-112V. Answers cannot be translated.
And here are the questions.
1. Was there such a need for prototype flights at exhibitions?
The prototype did not spend much time in the air, the longest flight was just the flight from Voronezh to Moscow. All other flights lasted from 5 to 10 minutes. They did not risk it, circling over the plant, the whole city saw it. There are now residential areas around VASO everywhere, so such jumps were very, very justified, thank you.
For a whole year, from March 2019 to March 2020, the plane did not fly at all. They tried to bring it to mind, at the same time repairing the runway of the plant.
2. Has it been examined in detail, whether the identified shortcomings, which have been worked on throughout the year, have been eliminated?
3. What is the Il-112V made of? Duralumin grade D16, from which the aileron thrust was to be made, must withstand a critical temperature of 650 degrees. However, according to experts, the thrust lost its properties at 600 degrees.
4. Will JSC "UEC-Klimov" be held liable, which for so many years has not been able to ensure the performance of the Ukrainian semi-licensed engine, which it offers under the TV7-117ST brand? The engine is frankly not ready for operation on airplanes, but we obviously have 1941 again and no engines.
5. "Truncated" fire extinguishing system: who came up with this solution and why?
And the last question. Is the life of test pilots Hero of Russia Nikolai Kuimov, Dmitry Komarov, and test flight engineer Nikolai Khludeev really worth it for show at exhibitions and forums?
There is such a desire to advise our officials in the Ministry of Defense not to be like the figures from our Soviet past, who "at any cost" ordered the impossible to be done by the next anniversary or congress.
Today, no orders and condolences will return the pilots. We still need to think about people, not about solemn reports.
- Roman Skomorokhov