DA40 diesel engine failure stats?

NicoKM wrote:

Never had any issues with any diesel engine except a couple of temporary ECU fails due to fuel pressure dropping for a fraction of seconds below threshold (reported in the Garmin G1000 log).

385 hours on a DA40 with Thielert 2.0 flown between 2008 and 2016. I had fuel pressure problems including a scary partial power loss. It was likely maintenance-related.

The DA42 NG (and I guess the -VI) with Austro also require weight in the baggage if flown with 2 people in the front seats only…
The only real difference between Austro and Thielert/Continental I noticed is the Austros start really immediately every time, the others need few seconds more cranking.

Never had any issues with any diesel engine except a couple of temporary ECU fails due to fuel pressure dropping for a fraction of seconds below threshold (reported in the Garmin G1000 log).
I actually really like the smoothness and ease of operation of diesel engines, I find the DA42 a great cruising machine and I love it!
Compared to the Lycos, you have to treat an electrical failure as a much more serious emergency.

Thanks for the useful data on the CD135 and CD155.

Emir wrote:

I’m pretty sure it would be more than 200 KTAS

That would be impressive and on par with “classic” air-cooled twins with twice the amount of hp like Cessna 300/400 twin series and the likes.

arj1 wrote:

Emir, right, so it is not worth it for retrofitting, but OK for the factory-produced?

Kind of

Both DA42 and DA62 with AE engines are nose heavy to a point that DA62 needs some baggage compartment weight if only front seats are occupied to remain in balance. As a side effect of forward CG come higher speeds Vs, Vmc etc. While DA62 definitely needs 180 HP engines (or more), DA42 is quite OK with 155 HP engines. AE with 2×168 HP brings a bit more power which is negatively offset with 2×52 kg of weight (134 kg vs 186 kg each engine) resulting with similar performance. Actually, AE powered DA42-VI is little better performer in cruise than CD-155 DA42-TDI but that’s more to aerodynamic improvements of -VI rather than more powerful engines. I can only imagine how would -IV perform with CD-155 engines but I’m pretty sure it would be more than 200 KTAS in cruise (DA42-VI with AE300 can reach 197 KTAS while DA42-TDI with CD-155 reaches 185 KTAS in same conditions due to lower critical altitude).

Emir, right, so it is not worth it for retrofitting, but OK for the factory-produced?

Emir, why not the Austro E4 ones?

Too heavy. So changing Thielert to AE300 requires expensive airframe and landing gear changes, resulting with more than €350k just for engines exchange and probably 6 months of AOG. Replacing Thielert with CD-135 is just cost of engines plus labor. I guess that total cost of installing CD-155 via Crosby STC today is around €150k which includes pair of engines, new scimitar propellers, changes to cowling and cooling, STC and labor. If you keep old propellers, it €30k less. Diamond’s CD/155 STC is more than €180k.

In addition for AE300, initial limit of 1800 TBO is changed to 1800 TBR due to overhaul being more costly for the manufacturer than producing new engine.

The advantage of full AE300 upgrade is that you get the aircraft aligned to current production specifications which means latest hardware and software capabilities minus 100 kg MTOW (upgraded aircraft is 1900, new one is 1999). However, that comes with cost of more than €550k.

Emir wrote:

CD-155 are probably the best engines for DA42, rated 2100 TBR.

Emir, why not the Austro E4 ones?

Both engines replaced at TBR time 1500 hours On a tangent: why?

Because Thielert 2.0 were 135 HP engines which was not enough for DA42, it was simply underpowered. Besides that I didn’t want to run engines on condition while changing gearboxes every 300 hours which was mandatory on that generation of engines. CD-155 are probably the best engines for DA42, rated 2100 TBR.

1200 hrs on two CD135 2nd generation (2.0L). Operated them cautiously, 70-75% in cruise. The only issues I had were about five ‘ECU-failures’ which were nothing more than these units tripping because of spurious sensor signals, and only required a reset.