Computer redundancies.

[Fox Pass]

A thread in another engine group got erased when the question of computer and sensor redundancy was asked.
My question is regarding any experimental engines that use computer control.
Are there two computers?
Are the critical sensors in pairs?

[Fox Pass]

The thread was back today, and though there was no definitive answer as to redundancy, there was two take always.
First they have never had a problem in there fleet.
Second was that any of the parts of the system could be replaced at some interval that made the owner comfortable.

Boy all the redundancy’s we build into aircraft I automatically assumed any computer system that controls the engine would be redundant. Now I’m finding out pilots are willing to go up with one computer with one set of sensors.

I got think about this some more🤔

[Av8r3400]

All bets are off with experimental.

One of the new engines people are raving about has single ignition, one plug per cylinder, single ecu, maybe redundant injection pumps, but a single electric oil scavenge pump...

[109JB]

Even production airplanes have single point failure modes. Sure they have redundant ignition, but they still only have one carburetor or one fuel injection system. Just one diaphragm failure on a precision fuel injection servo will cause a Cessna or Piper engine to go silent. Also think that a modern car has one engine control computer. Now think about the reliability of that modern car and if you are old enough, think about the reliability of your old carbureted cars. Not telling you what to do or what not to do, just letting you know some of the thought process.

[neville]

I have a Kitfox SS7 with a Rotax 912iS computer controlled fuel injected engine. There are two identical computers, two injectors in each cyl, two ignition coils for each cyl, two built in alternators. two electric fuel pumps. During normal operation one alternator is used to power the computer system, ignition system and the fuel pumps. The other alternator powers the normal aircraft electrical system. Also during normal operation one computer controls one set of injectors and one set of ignition coils while the other computer controls the remaining sets of injectors and coils. For different failure situations the computer programs take all sorts of specific actions depending on the type failure. The engine will operate just fine on one computer to the extent that the pilot would not know that one computer system failed except for the alarms which would be displayed. In the event both alternators were to fail the pilot would then switch the aircraft battery to the computers, restart , and the engine will run until the battery is depleted. If that were to happen the astute pilot would seek a suitable landing site. Diagnostics for engine issues is done using a laptop computer with an installed engine maintenance program. The computers record many aspects of engine performance and display any problems by a fault code system and a engine heath page. At every 100 hours the computer data is extracted to a USB memory stick and becomes part of the engine history.

[Fox Pass]

Wow that’s a lot, but this is more like what I was expecting.