The control system Superdzheta

Russia can be rightfully proud of its new civil aircraft designed by our engineers and designers. His excellent aerodynamics and control system says one of the founders, Alesandr V. Dolotovsky. Just as he spoke about the history of the project, the reasons for the choice of this dimension, and the preponderance of the economy, fuel costs and benefits over its competitors, as well as about the future Superjet-130 and many more. Read the second part of the interview

The first part of the interview AV Dolotovskogo

And the new, for us, the draft Superjet. As part of the certification, we "discovered" that the civil aircraft industry in the West has become the norm, namely that even fairly old aircraft, such as all Boeing 737 family, have a very good stall characteristics. This means that there is no tendency to stall the wing of such intensity that the average pilot who can not fend off. For us, it was a small revolution, the fact that we start unmanaged rotation around one of the axes of the plane was taken as a sign of stalling. So until now teach students aviation universities in Russia.

And we have set ourselves the task to meet the most advanced requirements in terms of the behavior of the aircraft at high angles of attack and stall, namely the aircraft must decelerate on the back centering the way of taking control lever towards you (thus achieving the combination of the maximum angle of attack and the minimum airspeed) while it should not have tendencies to stall the wing or overload pickup (aircraft nose up sharply) than often sin aircraft with a T-tail, , the response to the deviation of controls should be just a straight line.

This task failed.

How so?

In general terms the answer is that — through judicious selection of the location and size of feathers, as well as by optimizing the geometric and aerodynamic twist of the wing, including artificial (ie, due to mechanization, flaps and slats). Moreover, in the optimization of profiling, which I mentioned earlier, we have set and solved the problem of exclusion, or at least minimize, the so-called "spoons", ie zones static instability local angle of attack across a range of angles of attack up to the maximum.

What have we achieved?

When tested in a snap pipe TSAGI model of our aircraft were able to "throw" in a tailspin is not the first attempt, and it is derived from the spin simple statement of rudder to neutral. In a flat spin model is not included, even when fully deflected over the height of the handlebars. This is a very good result, noted in particular that for the first time in its history, TsAGI gave us the conclusion of the flight at high angles of attack and stall without a parachute or antispin antispin missiles. 

Vladimir Biryukov — honored test pilot,

During the flight Test confirmed that we really got a remarkably good result. Vladimir Biryukov — honored test pilot, the certifier of the Gromov Flight Research Institute, with a very large experience of flying on Test high angles of attack not only on our own, but also and foreign aircraft to fly in our car in November 2008, admitted that such good stability and controllability at high angles of attack he had not seen on any civilian aircraft.

This was expressed in the fact that the aircraft could reach the angles of attack of 30 degrees, slow down to a speed below 200 km / h (for aircraft with a wing loading is very small), and thus continued to operate in all three channels, even from the pedals without any tendency to unexpectedly stall. That is, stalling for RRJ — is the move to parachute when the plane almost falls flat (after lift at level flight at this time is not enough, the overload before output falls to 0.6), but the plane crashes and controllable output from this state of simple actions of the controls, apparent to the ordinary, average pilot.

And this is the final chord in favor of our aerodynamics.

What have we gained as a result, besides the possibility to surprise our experienced handling of test?

We got a good take-off and landing performance, taking into account the fact that the thrust-to-weight and wing loading of our apparatus are on the border of Statistics. And it was not done by accident.

Questions and Answers

Which engine — and a thrust.

The engine was designed under this draft. In this gasifier could be made with greater engine thrust.

But it did not.

Did not. Let me explain why. The cost of engine maintenance and a number of other parameters that are not directly related to performance, but connected with money directly dependent on the draft. For example, the engine is sold on draft in kilograms. So it was done intentionally limited engine thrust to lower the cost of maintenance2 the entire aircraft (and increase the life of the engine.)

Here this approach, to be honest, I have not.

Consider that opened a trade secret. Joke. Again, if we look at our position among competitors specific load on the wing and the specific load on the rod, you will see that we are at the lower end statistics. But our takeoff performance — a balanced take-off distance, restrictions on take-off weight skoropodemnosti performance in hot and high altitude — we are not worse than the competition.

Close to the Yak-42?

Yak-42 is much better than us in terms of thrust-weight ratio. Still, once the engine has an effect. And he has a huge wing. It in fact was a famous story, almost an anecdote, when the transition from direct to the swept wing, they had to make the wing more than 140 meters of the area by car of the same mass as we have. We’ve a small wing on the trapezoid only 77 meters. But thanks to this we have a very high percentage of implementation: cruising quality — 90% of maximum. Ie we use the wing to the fullest and on the rise, and in the cruiser, and on landing. Excess we carry with them not.

By the way here helped us a lot of Siberians SibNIA, thank them for that much. They are in fact a lot of experience to optimize the landing of mechanization. Let’s see, we are not very large high lift system, is not as prominent as, for example, on the Tu-204, which has a magnificent mechanization of geometrical parameters (the chord and advances). But even with our relatively small slat, we got a very decent boarding Cv = 2.5, which is by far one of the best indicators for odnoschelevogo Fowler flap on the wing sweep.

On the next machine should be installed strengthened wing, how it differs from what we have now?

Strengthening of the wing is not my diocese, I’m sorry. But I can confirm that the geometry of the wing and the mechanization remains the same. Why are we going to strengthen the design, I think, is obvious. Already everywhere we rinsed for what our airplane is a bit heavier than originally pledged. Yes, it is. Indeed, the empty weight increased by 12%, and this is almost 3 tons. And that we had to move a ton of weight in the empty take-off, for what would have declared 3000 km distance we covered, as promised for the base model. The fact that the design of our chief designer Yuri Viktorovich Ivashechkina laid project reserves, and that allowed us to maintain the characteristics of the basic model, while increasing the weight of the empty aircraft.

Incidentally, this weight gain has had a negligible imp
act on the economy
, because basically, to the shoulder in the 500 nautical miles, the effect of increasing the weight of an empty 12% of fuel for the flight is less than 4%. This is due to the fact that when flying on short routes weight component of the fuel in the cruiser is comparable to the fuel that is consumed in total, to take off, set, descent and landing. And these components are not changed by increasing the weight of the empty. On the cruiser weight gain itself is empty gives the deterioration in the ratio of costs of approximately 0.5% to 1% of the fuel weight, ie 11% of excessive fuel consumption, which I read in the press, no more than a speculation. In fact, according to our estimates, we have the advantage of mass-produced cars on fuel for the flight to the EMB-190 a little more than 2%, when compared to the A319 — that more than 12%, with the same load, of course.

Now we need to do a version of «Long Range», which has not been canceled, in fact, customers are waiting for this car. Take-off weight LR goes to the area of 49 … 50 tons. But under this model, and we need to strengthen the design, but, I repeat, it is local, local amplification. They take into account the results of static testing machine at TsAGI and resource in SibNIA. And these local gain associated with the resource and static, is a normal process. Here is an example of our own stories. After the war, launched the famous Tupolev Tu-16, which became not only our main bomber, but the prototype of the Tu-104, it is no secret that the machine is run twice. First plane designed, say the "old way" under the 100% strength, was very heavy and given LTH did not give. Then clever AA Archangel came up with the idea: instead of what would be "lick" the extra pounds with pereuprochnennoy design, design a plane for smaller reserves of strength and experience to 100% and the results of tests to determine the places of local reinforcements. Did so. With the machine was removed several tons of weight! Since aircraft trying to design a minimum margin, in order to minimize the weight of the structure. And I want to note that we have a weight-optimized achieved. That’s why we are strengthening it locally by individual seats. It says in part because we have to static machine wing broke at 99% of rated load, and this is a great result of prochnistov and designers. To say there is not that the aircraft turned hard, on the contrary, OH Get easy. It is lighter than all of its competitors, even physically (EMB-190 is heavier than 700 kg), and given the size of our fuselage, in respect of the specific even easier.

And why, assuming that the car will not weigh 24.5 tons, we still have stated these figures? A Look around you! This is the feature of our age, no one declares the real values to complete the certification. So it was with the A320 and the B737 NG, and with our direct competitor to EMB, and Dreamliner B787. This is done for reasons of marketing, far from understanding the designers …

By the way, how much was pumped at resource car in Novosibirsk?

Not even aware of. This information is most likely knows Igor L. (grape). This indicator is under the constant control of the upper as well as a resource — it’s selling feature.

And Vinogradov IL satisfied my curiosity a little later, he received a call this number — 21000 cycles3.

For IL-96, this figure is 70,000 flight hours, we would like to, and for this aircraft was not less.

I note that for our type of aircraft that number 70,000 flight hours is much more expensive than for IL-96. Because for main machinery standard cycle length from 6 to 12 hours, and have a standard 1-2 hour cycle. That is, the number of cycles on the same number of flight hours at times, and sometimes much higher. Speaking of which effective a / k knows, taking on lease aircraft. The cost of leasing depends on the value of the aircraft, and the number of remaining cycles. So while the car is new, its race on short routes on the cycling routes, beating cycles. Then it is usually sold to those who usually starts its drive on long routes, selecting "Calendar" resource in hours.

Selecting dimension

Several digress and say a few words about selected measuring machine. The question Why have got in this niche has been discussed quite often, so I want to answer to another question, Why do we need these aircraft?

In those days, when the price for a barrel of oil exceeded $ 30 widebody aircraft with a load less than 75% of the fly was not profitable. But when the price of the barrel began to grow and grow, and today it is, as you know, keeps around $ 100, there is a need to create a plane that would be cost-effective and fills 100%, where the B-737 and A-320 are filled below return (which is around 80% of the aircraft occupancy). Accordingly, there is an obvious way to reduce dimensionality. In addition, for a start-up and (buzzword means a company-novice) this meadow with the lowest possible competition is much more favorable than, for example, the dimension of more than 200 seats, where the play actually state giants Boeing and Airbus.

But there is a technical dilemma, because reducing the dimension we automatically degrade aerodynamics. Reduced local Reynolds number, which is a direct blow to the aerodynamics, as reduced area of so-called laminar flow over the surface. For example, the machines of our class maximum achievable glide ratio — 16.5 … 17.0. But if such a plane stretch, say, twice, this figure will immediately become greater than 18, only by dimension. Therefore, we had to crawl through the "eye of the needle" Optimization of the wing, as I said at the beginning of our conversation.

So we have reduced the dimension of the machine, as a result, we obviously won the title we won in the cost of servicing the machine, due to the fact that they took the cheaper engines and have a lower take-off weight, but we have a glide ratio is close to the A-320 . The result was a plane that carries 100% load, where even the A-319 will carry only 70%. As I have noted, the savings on fuel alone is more than 10%! And then there are the savings on the cost of ownership, TO, airports and air navigation services. As a result, accumulates a large percentage …

To illustrate this fact, in the west, instead of our parameter grams / per passenger / per km, that in the practical economy can not be used as this parameter reaches its minimum near the maximum range, which is different for all aircraft used chart Fuel for the flight / fuel on a chair. On one axis the fuel for the flight (what you need to spend), and on the other — that fuel consumption on a chair. This is done for a fixed standard range. Obviously, the left and below we are in this diagram, the better plane. So, when we take the plane of regional class, and compare it with the 150 … 200-seater car, it is obvious that we (as any regionalnik) lose in the fuel indicator on the chair, but on fuel for the flight we always win! This is a direct indication of airlines flying on schedule, that the fall in passenger lines have to move to lower-dimensional planes to at least not lose money.

That is why in this segment of the market in the 90s rushed first Bombardier, who, sensing the smell of money, he stretched his business jet and made 50 first-place, followed by 70-minute and 90-seater car, then jumped to the same Embraer making its family of E-Jet. At that Embraer is very well grasped the idea that the consumer is waiting for a special … 70 100-seater aircraft. Do not stretch the car business, as did Bombardier and do not cut the main jet is at the same time, Boeing and Airbus have made with their machines. Short stacks were unprofitable.

That is why in this niche and we went. Do
not forget that our commercial project from the outset and extrabudgetary funding is still a major, that would not shout about it, our "well-wishers". Play on par with Boeing and Airbus can only be powerful gos.podderzhke, which now have a project Irkut MS-21.

The only thing that made Embraer is the size of the fuselage, they were still below the psychologically from their small regional aircraft of the ERJ-135 … 145. For the E-Jet they chose dimension 2 +2, but it is at least more than the CRJ but nevertheless still fairly small. On this we are now played. When we laid the size of his plane, we knew Embraera dimension, and we recognized that our plane must exceed EMB-190 primarily for comfort. Thus, the passenger transit flight coming into our plane, I felt the same level of comfort as on A320 or B737.

The level of comfort

What you can feel his body went into the salon?

This is primarily the presence of space for passengers, which is comparable with the main plane height in the aisle, aisle width, seat width, pitch between seats, height, width and depth of the luggage rack. I stress, not of shelves, namely the height, width and depth.

As a result, now that you and your colleagues, went on a plane, do you feel the difference compared to the A320? No.

And Aeroflot passengers also note that. But this is especially noted the Europeans and the rest of men, who, unlike you and me a lot of fly CRJ and EMB. You know, for example, that the CRJ hand luggage, you just drove to the shelf on the A320 or B737, shall be in front of the plane and fits into the front trunk? And this is the only way, the cabin baggage for that has no place.

As a small addition. One flew to Paris with an intermediate transfer in Zurich and drew the attention of the Europeans, without a twinge of conscience, dragging their suitcases into the cabin, and stuffing them in overhead bins, when suddenly something not fit, then the flight attendants to help build out in the cabin. And it’s kind of par for the course. Flew Suisse.

SSJ-130

Due to Economy class seats with a step 29 "103 … 105 seats, why go for 130-seater car may need to go further, for example to the 150-seat car?

Why a 130-seater car? The fact that the market has several air transportation centers of gravity. Once there was a shock to the growth of oil, and transportation center of gravity on regional routes has shattered such centers upon two. One is in the area of 50 seats, and it is fully captured TURBOPROP and small jet engines type CRJ200, CRJ700, the other goes to the dimension of 100-120 passengers. In addition, the current level of profitability for the airline transport is important to always maintain a high percentage of seats on the occupancy optimized for this size aircraft. The selected diameter of the fuselage makes it relatively easy and quick to do 130-seat car that will fill the gap in our family, formed after the failure of the 60 and 75-seater vehicles. 130-ka is obtained not only comfortable and lightweight machine, but that it is encouraging for us, the aerodynamics of the wing due to the larger returns us to the type of single-aisle aircraft. Because of this, for this arrangement, we plan to have a glide ratio, by no less than 18. And it gives us a very good win for the economy, even without new, advanced engines! It is also important that this machine is becoming a competitor younger members of the family of B-737 and A-320, is still not a competitor to Boeing and Airbus in their primary segment, 180-200 local and wide-body aircraft.

Remote control system

A separate topic of conversation deserves our remote control system, which incorporates the experience of almost all of our aviation industry, including even the "Buran".

Changes wing plumage varies, but the filling is also changing?

Our stuffing is the most interesting thing in the plane. "Pipe", ie glider is the cheapest that it is. But the glider and must be cheap, because it intellectual component is not very big. After development airframe design techniques, including aerodynamics largely been in the past. Modern designs are developed using existing, highly efficient design methods. But controllers (total of somewhere around 15-20 pieces), aircraft control systems, which were developed during the design, often created with a base, or even zero. But that’s not the point.

All the software for the management of the electronics is written, in fact, us. All control logic is written by us. This intellectual property, which appeared during the creation of the aircraft.

My single pride — is the control laws CDS, written jointly with the Directorate of aerodynamics experts NIO-15 TsAGI, about which it will be necessary to tell apart. And this logic, the principles of management and interaction, do cost a lot of money and VERY easy. So when we go to a new machine, changing the wing, empennage, something in the fuselage and leaving unchanged on-board electronics, we are very healthy and save money and time.

Today, we, I mean the aircraft industry, in fact came to the same, that is called in the automotive platform. Note that the last thirty years, automakers change model on the line every few years. But really it’s turning inside out of the same base of the car — a platform that is changing much less frequently. Once every ten years on average. So here, too, for aircraft already formed the concept of the platform. This is what is spent on the development of maximum effort, time and money. It is very important to have this platform and lock.

The first, of course, did Boeing with its 737-m family. They grasped the idea and was notified. Then the idea started to use all manufacturers. And mind you, that the planes of one family may differ in the airframe is very serious! But there are some "common points", which are the same for all aircraft family.

This is the platform. As a rule — it + avionics cockpit. And the principles of MOT and logistical support and much more …

In the same way, and we’re going to go. We have a platform. By the way even very good, much superior to even the level of long-haul aircraft. For what we are "paid" in the operation. The crews of the same Aeroflot hard to compare our A320 aircraft, completely forgetting that the RRJ half and as many times cheaper! But they see no difference in principle and require the same level throughout. Therefore, we perceive their criticism constructively, often with gratitude and even, in a sense, as a compliment.

So, we call our platform complex avionics and cockpit. And they have already. A new wing, empennage and mechanics can now be done in a relatively short time and with less risk.

Control laws of the CDS

Now, as promised, talk a little about the control laws of the CDS (Remote Control), and also about the system itself. Probably everyone knows the main "slogan" of our CDS. The world’s first fully remote, with no mechanical backup system, so even with the side handles as the main lever. Ask how did we get to this? Back in 2004 now we held the third collection Advisory Board with the airlines, which came giants such as Air Franc, KLM (then still apart), Lufthansa, Delta, etc. In this collection we have presented an ideology as cabin crew uniform with V737 — as it seemed to us — the benchmark best-selling short-haul market. Accordingly, the CDS was primitive by replacing direct mechanical linkage to the damper on three channels and the optimization of the minimum specifications for flight modes. Grandees of world aviation business greeted the idea with lukewarm, saying that the new aircraft should be focused on the future (as would say today — on innovation), and the most promising is the ideology of the protected
aircraft used on the Airbus A320 family. It is not that the idea was alien to us. All the same, and the fighters, and the Tu-204 has been used algorithms for automatic restrictions go beyond the operational area, ie necessary base in our country had. Also, back in the 80s were tested at FRI promising side handles on the Tu-154 LL number 317, and even had the idea to put it on the Tu-204 (unfortunately zarublennaya standing on the top level of leadership MGA). And our supplier LLI (Liebherr Lindenberg) expressed full readiness to provide us with the necessary level of efficiency and backup computer and the executive part of the CDS, sufficient to implement a full set of algorithms. So the base was, and bad.

And we started this business. I’ll be honest, the work was difficult, but fascinating. Something we took from TsAGI (basic integral part), something assembled at A320, and a lot have created yourself. For this, we used the most actively modeling stands, ranging from the simplest, and PC-based gaming joystick and pedals (they are still lying in my closet), and ending with the most complex mobile stand TSAGI PSPK-102, which was built back in the USSR Buran program, and is now used for virtually all applications requiring high-quality full-scale simulation. Note that this stand even uses Boeing, in spite of its own, a very solid base of bench.

What do we got the result?

Our CDS has the following tasks:
Lightens the load on the pilot due to:

  • Automatic balancing via pitch and roll with the liberated management.
  • Optimize the handling characteristics on the flight modes, taking into account the position of the wing, speed, flight Mach number and position of the alignment

Provides protection from falling into the complex spatial position by

  • restrictions pitch and roll angles, with the return of the aircraft to the limits of the main operational area for these parameters in an abandoned administration;

Provides protection from falling into a stall mode with a critical loss of speed due to

  • limiting angle of attack, pitch and roll,
  • the ban on harvesting of the wing at an unacceptably low speeds;

Provides protection against structural failure due to

  • limiting airspeed and flight Mach number, and taking into account the provisions of the wing
  • limiting the maximum normal overload with the configuration of the wing
  • automatically adjust the position of the wing
  • automatic limitation rudder deflection angles, depending on the speed of the instrument and the number of flight Mach
  • automatic limitation of the pitch angle during take-off;

Provides protection against loss of ability to maneuver at low speeds and altitudes due to:

  • Automatically increase engine thrust to takeoff on modes with a critical loss of the total energy of the aircraft (remember that the total energy is the sum of kinetic and potential energies);
  • Automatic release of the wing in position "1" (actually slats) the loss of speed is below a predetermined threshold.

And it works even when the failure of two hydraulic systems or switch is powered by the backup power supply (RAT or in Russian — windmill). This feature set is sufficient to prevent a catastrophe such as those that occurred with the A320 near Sochi, on the B737 near Perm, a Tu-154 near Irkutsk and near Donetsk, with ATR42 near Tyumen, and many others associated with a hit in NGN (complex spatial position ), stall, a critical loss of height to maneuver.

And where to go initially developed, primitive algorithms under wheel control?

They switched to a minimal, stand-by mode. Thanks to their own characteristics and good stability of the aircraft, in «DIRECT MODE» RRJ like our good old Tu-134. I will not reveal the secrets when I say that in this mode we will just quietly raised the plane in the air, but it flew more than three months of test flights, if you take the amount for the whole program. By the way, some of our pilots «DIRECT MODE» like it even more than «NORMAL», because in this case, the plane does not limit the pilot, and handling characteristics differ little. And by the way, this is also a great achievement, because, for example, on the same shift in the A320 «DIRECT MODE» pilots during training only show on the simulator and only in flight, and we can perform a «DIRECT MODE» all flight, and the plane with the pilot still available mid-level training.

So on our jet flying characteristics really super! It is especially important that that its "filling" is wholly owned by SCA.

Now a little about hardware. Since the CDS projected without fur. reserve, the reliability requirements laid hoo what! For this we have to thank the IAC, quite frankly saying. But this machine was designed for a given value, ie I had to make a "cheap and nice" that seems to be impossible, but the Russian creativity in the alloy with German thoroughness, as it turns out, can do wonders, worthy of the memory of Lefty, a flea-savvy. I will not go into the jungle is quite simply say that given the price / quality modern calculators on board actually stretch a two-level network structure, with so many "nodes" — computers that talk about reservation in the traditional approach in the channel-is impossible.

What would "knock out" a system, it is necessary to destroy more than 70% of the computers, which, given their heterogeneity on hardware and software, is almost impossible. However, as I said, through the development of technology in the development of microelectronics segment of so many calculators cost is relatively cheap, and despite the fact that in our CDS number of calculators is greater than the A320, below the set price of the CDS, with higher reliability.

In addition, this structure provides a very large increase operational flexibility due to the inclusion of non-performing units in the MMEL. For example, the flight schedule we have available4 for any crashed calculator and three top-level calculators failed lower level. We assume in this case the refusal of four drives, with the condition that at each height of the steering wheel and the rudder remains one running the drive. Departure for ferrying possible when one is running the calculator upper level and an even larger number of non-working equipment on the "ground floor". But frankly, for the whole test period, we have not taken advantage of this opportunity, because failures in the CDS was not due to equipment failure. Quality made in Germany, however! Incidentally, our CDS, as well as other controllers on board tested not only in wire breakage, but also to short-circuit, as well as on EMC and HIRF. The amount of testing, unprecedented for Soviet and Russian aircraft, fully confirmed the correctness of embedded solutions at the level of the system architecture. Critical points of the CDS RRJ has not. This intellectual property is our common with LLI, because architecture development was carried out jointly.

Epilogue

Perhaps this is more than enough for a short meeting. Believe me, I have more then tell you about our project and about our wonderful team, which brought together experts from almost all of our aircraft industry. We employ people not only and not so much with the Sukhoi. There were people and of Ilyushin, Tupolev and on and on Mikoyan (I did there), and from Yakovlev. For example, our small team of aerodynamics combines experts from TsAGI of "Lightning" from Ilyushin and even Embraer … In addition, we have a wonderful young people, who over the years has become a world-class specialists who are ready to work on equal terms with Boeing and Airbus, confidently prove the correctness of their decisions not only IAC but EASA, and run and FAA.

Therefore, in spite of the fact that o
ur work is not an easy one, I am optimistic about the future and believe in the fact that our first project will be the pioneer of the whole line of planes that really revive our aviation industry and bring it to a whole new level!

Thank you very much for your questions, Vladimir. It was very pleasant to talk to.

Sadif: I want to thank you for the attention you paid for the answers to the questions of aviation enthusiasts. After the preparation of this interview you did a lot of personal time spent to fix those neskladuhi I allowed the preparation of the material.

So I would like to thank the designers and test engineers Alexander Dolotovskomu, Podorvanovu Igor, Igor Sobolev patience for my stupid questions, and for the time that I paid, and I hope I can still have them tear off a piece.

In short, common to our engineers, who gave his work no matter what.

 

Now a little about hardware. Since the CDS projected without fur. reserve, the reliability requirements laid hoo what! For this we have to thank the IAC, quite frankly saying. But this machine was designed for a given value, ie I had to make a "cheap and nice" that seems to be impossible, but the Russian creativity in the alloy with German thoroughness, as it turns out, can do wonders, worthy of the memory of Lefty, a flea-savvy. I will not go into the jungle is quite simply say that given the price / quality modern calculators on board actually stretch a two-level network structure, with so many "nodes" — computers that talk about reservation in the traditional approach in the channel-is impossible.

Valery Popov: I’d add that the result was. When certified EASA their experts have paid great attention to failures affecting the strength. At the same time, they worked quite simple — compared the list of failures of A-320 with ours, when we found discrepancies asked — why the A-320 is, for example, the failure of the form samopoizvolnogo deviations of more than one control, and you do not? In response, we showed them the probability of failure of the order of 1E-20 or 1E-23! Sometimes it simply is not believed required and conduct tests, despite the fact that the probability of failure was below 1E-9.  

 

Full interview: http://superjet.wikidot.com/wiki:dolotovsky

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