How does the dual ECU redundancy work?

RotaxOwner Admin wrote:

We're currently preparing some new user-friendly supplementary educational materials on the 912i/915i platforms. But in the meantime, you can find a pretty good description of how the two ECU computer modules interact in the 912iS Operators Manual, section 7.5.1...

https://www.rotax-owner.com/en/support-topmenu/engine-manuals#912-i-series-engines

I'll look forward to reading those materials thanks!

Some of the redundancy for Rotax I think really is important like dual fuel injectors, duel spark plugs and etc. I've read that the fuel injectors and spark plugs are only used one at a time and the injector/plug that is used alternates on each cycle so the ECUs can tell if one of them failed, which I think is brilliant. That kind of redundancy is important and I think most other manufacturers don't realize that. That is the sort of thing that would be cool if it were documented as a safety feature.

Pilot Joe,

  you have clearly decided, and that is fine. Your comments are full of "Probably" "assume primitive QA" "I bet" " I guess" etc.

However for others that are reading this thread. I have actually done extensive testing on an Automotive ECU including EMF testing, vibration and humidity testing etc.

We could NOT make it make an error and concluded it was rock solid, therefore we were comfortable using it and never had any issues.

If someone really wanted to compare the RC and Autronic units it would require unbiased physical testing over many hours. If you do not want to do the testing then you are back to "belief". You "believe" that Aviation electronics are more reliable...then go with your belief and use the RC unit...

Oh and also Never never read "No mans land" about Qantas QF72 or read any articles about Boeing Max aircraft...then you will feel "comfortable" and enjoy your aircraft and that is of course why we fly to have fun !

Glenn Martin wrote:

Pilot Joe,

  you have clearly decided, and that is fine. Your comments are full of "Probably" "assume primitive QA" "I bet" " I guess" etc.

However for others that are reading this thread. I have actually done extensive testing on an Automotive ECU including EMF testing, vibration and humidity testing etc.

We could NOT make it make an error and concluded it was rock solid, therefore we were comfortable using it and never had any issues.

If someone really wanted to compare the RC and Autronic units it would require unbiased physical testing over many hours. If you do not want to do the testing then you are back to "belief". You "believe" that Aviation electronics are more reliable...then go with your belief and use the RC unit...

Oh and also Never never read "No mans land" about Qantas QF72 or read any articles about Boeing Max aircraft...then you will feel "comfortable" and enjoy your aircraft and that is of course why we fly to have fun !

 

My comments have lots of "probablys" because I don't know anything about Autronic SM4, only other "generic" embedded systems (not ECU) and those systems have very questionable reliability. If you have done extensive testing on these things then you obviously know more than me about them. What safety features do they have? Do they do internal self-checks or have ECC memory? If they did then that would make me feel a lot safer, even without dual processors for redundancy.

I see Autronic prohibit use in aviation and say that they are not reliable enough. Surely it's because they don't want to be liable to being sued but I know nothing about them and that's what made me skeptical. My impressions could be very wrong and I'm open to education about this.