Does each engine have an 2 ECUs

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catmando
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Does each engine have an 2 ECUs

Post by catmando »

Or are there two ECUs for the entire plane?
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Re: Does each engine have an 2 ECUs

Post by ultraturtle »

2 for each engine, and they automatically switch when one fails
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Re: Does each engine have an 2 ECUs

Post by dselder1962 »

ultraturtle wrote: Fri Jun 21, 2019 2:40 pm 2 for each engine, and they automatically switch when one fails
Yes, they do, although that two seconds or so that it takes feels like a lifetime...
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Re: Does each engine have an 2 ECUs

Post by Davestation »

To clarify, there is one FADEC for each engine. Contained within the FADEC is a pair of redundant ECUs.
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Re: Does each engine have an 2 ECUs

Post by CFIDave »

Davestation wrote: Thu Jul 04, 2019 8:36 pm To clarify, there is one FADEC for each engine. Contained within the FADEC is a pair of redundant ECUs.
Maybe I'm a stickler for terminology, but FADEC is just the type of control provided by each of the the engine's ECUs A and B. An Austro or Continental diesel engine has a single Electronic Engine Control Unit (EECU) that includes within it a pair of Engine Control Units (ECUs) A and B. Each ECU has its own associated backup electric fuel pump, and its own independently-operating hall-effect sensor in the center console to determine throttle position.

The pair of ECUs A and B do however share some common sensors on the engine, so if a shared sensor erroneously generates a value that is out-of-range, the pilot will typically see failure annunciations on the PFD for both ECUs ("ECU A FAIL" and "ECU B FAIL"). This (IMHO misleading) set of messages does not generally mean that either ECU has failed. It means that each ECU is continuing to operate in a less-than-optimal fashion, with software typically assuming an average fixed value for the failed sensor. The engine will continue to run, but perhaps at reduced power, and/or generating more pollution than if the sensor hadn't failed.

See attached photo of a flight I made in a single-engine DA40NG with G1000 NXi:
IMG_3074-1.jpg
An easily-replaced fuel sensor on top of the engine had failed ("infant mortality" on a brand new airplane). It turned out that fuel pressure remained normal, both ECUs continued to operate, and the engine kept on running just fine.
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Re: Does each engine have an 2 ECUs

Post by TwinStarScott »

the pilot will typically see failure annunciations on the PFD for both ECUs ("ECU A FAIL" and "ECU B FAIL"). This (IMHO misleading) set of messages does not generally mean that either ECU has failed. It means that each ECU is continuing to operate in a less-than-optimal fashion, with software typically assuming an average fixed value for the failed sensor. The engine will continue to run. . .

Last winter, had a similar event happen in my DA42 TDI with the CD-135's, with a legacy, non-WAAS G1000 - which only gave the old yellow caution warning:

L ECU B fail
L ECU A fail

While at the exact same time the oil pressure gauge simultaneously dropped to zero in the left engine. Yet never received a PDF Alert (RED) or a continuous aural alert, just a single ding in the headset. For a split second, I thought "why is this engine still running?"

Fortunately I had just read Dave's posting on this subject (different thread) and his sage advice immediately came to the forefront - which made the situation much less stressful and soon landed uneventfully, with no detectable power loss in the left engine.

Which is just one more reason why reading this forum can be so beneficial. All thanks to expert members who freely share their knowledge!

PS - this sensor failure could not have happened at a better time, in the landing pattern at my home base. Turned out to be just as suspected, a faulty oil sensor and was back up in the air in about a week. Now I carry spare sensors with me, should this ever happen again and far from home, say on a time-sensitive Angel Flight West trip.
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Re: Does each engine have an 2 ECUs

Post by ememic99 »

CFIDave wrote: Fri Jul 05, 2019 4:56 pm "infant mortality" on a brand new airplane
I like these euphemisms of ours for what is essentially bad product or lack of quality control. And we just accept that this can happen in $500k (or $1 million) product. How come that for majority of people it’s not acceptable when something like this happens in $50k car or $1k TV?
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Re: Does each engine have an 2 ECUs

Post by N503TS »

I had a warning for both left engine ECU’s just after I took off today. No abnormalities in engine power or speed was observed so I assumed it was a sensor fail. I expect it would have been very rare to have both ECU’s fail simultaneously so I did not panic. I laned fine, shut down, restarted and the error was still present so I had to drive 6 hours to Maine instead of an hour and a half flight.
Any recommendations on Northeast shops. For DA42 TDI service centers though the closest to me listed is Southtec Aviation in SC or XU Aviation in London. Anyone recommend anywhere else closer to Boston that could troubleshoot this?
Phil

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Re: Does each engine have an 2 ECUs

Post by CFIDave »

Phil:
Try TakeFlight Aviation at Orange Co airport KMGJ about 30 miles north of NYC. While operating a Diamond-oriented flight school (#1 school in the US according to last year's AOPA poll), they also have their own maintenance facility that works on Diamonds including twins. They can work on Austro diesels and possibly CD-135 engines like yours.
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Re: Does each engine have an 2 ECUs

Post by cptndavid »

My DA 42 is now at Take Flight for annual, they seem to be good.
I have had a few ecu fails which turned out to be the cam sensor. All you need is the cable and your computer along with the program to clear the fault.
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