# Superjet



## fliger747 (May 8, 2019)

I happen to be in Russia right now and there is some more awareness of the Sukhoi-100 project and the very recent crash at Moscow of one of Aeroflot's planes. 

I was a Boeing driver and the only "FBW" plane I flew was in the 747-8 with the "flare assist". So I don't claim any great knowledge of the in's and out's of fly by wire systems. The Sukhoi system is claimed to be a full FWB system with suffices redundancy to handle any issues. An acquaintance who is a Boeing Test Pilot mentioned that he had seen innumerable malfunctions that the engineers had assessed at a possibility of less than 1: 100,000,000. 

Watching the video of the touchdown as well as looking at the flight track I expect that we may find out that serious aircraft control issues were experienced. The skip on landing as well as the resulting inability to recover from the skip were commensurate with someone trying to control pitch with trim. I understand that is about all Airbus gives you. Perhaps some Airbus driver might be able to chime in. Certainly the apparent lightening strike may have found some vulnerability in the system.

Some info on the -100's FBW system:

Now few words about the hardware. Since the FBW system does not include a mechanical backup, the reliability requirements are very high! For this we have to say "Thank You" to AR MAK, i am talking seriously. Take into account that this plane was designed to fit into a predefined price, so we had to make it cheap and sophisticated, that seems to be impossible. The Russian creative approach in conjunction with German thoroughness is it turned out, are able to create a miracle. I won't go into complete debris, just let you know that taking into account the cost/quality of modern processing units, a complete two level network is deployed on-board, with such a large number of computer nodes that it's not longer possible to talk about a per-channel backup in a traditional way.

In order to "knock out" such a system, it is necessary to destroy more than 70% of computers, which is almost impossible given their heterogeneous hardware and software. At the same time, due to the development of a technology in the microelectronics segment,our system is relatively cheap, and despite the fact that the number of processing units in it is more than in A320, the FBW cost is lower, having a higher reliability.


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## fliger747 (May 8, 2019)

I learned from a source in Moscow that indeed there was a failure of the flight control FBW system and it was supposedly operating in Direct Law mode. My source suggests that this should not be a difficult task, but training was probably not provided. Also accident investigators are also focusing on the speed of the approach which was high. 

I should hope that this doesn't devolve unjustly into a blame the pilot situation if he is not to blame. Because of the political ramifications of the Sukhoi project this is always a possibility.

Reactions: Informative Informative:
2 | Like List reactions


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## nuuumannn (May 10, 2019)

fliger747 said:


> Take into account that this plane was designed to fit into a predefined price, so we had to make it cheap and sophisticated, that seems to be impossible.



Seen on the wall at an aircraft engineering workshop. "There are three types of aircraft engineering; good, cheap, fast. If it's good it won't be fast, if it's fast it won't be cheap, if it's cheap it won't be good."


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