Diesel vs Lycoming

[dgger]

However I think that this post is pointing to some issues with the Austro Engine:
viewtopic.php?f=17&t=5638

As the one who had voiced concern in the thread mentioned, let me chime in an drop my two cents on you.

The two incidents I had mentioned have been quite sobering for me personally, but I would like to caution to use anecdotal events such as mine to guess reliabilty of the Austro engine. A fair evaluation would require solid data (and a bit of math). Speaking for myself only, this would be the only acceptable way to come to an informed decision.

This is why I find it deeply troubling and disappointing to see both Diamond as well as the Austrian aviation authority to not only not report incidents and accidents, but to request/compile reports and then lock them away from the public eye. I feel an open approach towards safety as practiced by the NTSB and by and large the U.S. community of aircraft makers is a much more suitable way to build trust in a platform/engine/component.

The incidents I had mentioned occurred in a rental DA42 at a time I was in the market to purchase one. Actually I had already done a pre-buy on one. I then took some time to go through NTSB data (and added data from aviation-safety.net for the DA42) to make up my mind. In the end I felt reasonably assured that, based on my analysis and assumptions, the safety of a DA42 does not significantly deviate form that of other aircraft used for comparable missions. Funny enough I even felt good about the DA42 as I knew I could handle an engine failure in one - something I would not know about a SR22 or Seminole.

Long story short: I eventually went ahead, bought mine, and have not had a single moment of regret.

[reinhardj]

Manfred,

let me say directly in the beginning: I am a Diesel fan. We have our DA40 TDI with CD-135 now since 3 years and have flown approx. 500h without any incident. Of course the first Thielert 1.7l engines were a nightmare at least for some owners, but some of them are still very happy with these engines. Meanwhile the 2.0 (CD-135) and 2.0s (CD155) have more than 5 million flight hours and they are really reliable.
I want to point your attention to an article of the German magazine "AeroKurier" dated 12/2011 comparing the DA40-180 with the DA40 NG and the DA40 with Continental 2.0s (now CD-155). I can send you a copy of the article if you send me your e-mail address.
Conclusion:
- on ground there is nearly no difference between the -180 and the 2.0s, the NG requires longer take of diatance due to the increased weight of the Austro (approx 50kg over CD-155 and Lycoming)
- in the air the turbo of the Diesel engines are an advantage, as they provide more power at higher altitudes
I don't want to start discussions about running cost (lower fuel, no 50h maintenance etc.) but want to point out, that the TBR of the CD-155 has been increased to 2100h some months ago. The maintenance cost have been reduced over the last years, as the TBO of gearbox etc. has been significantly increased. During the last three years our DA40 TDI has only been in the workshop for 100h, 200h maintenance and ARC. As you know, in Germany we are bound to IHP and most probably CAMO, which reduces the possible work allowed for the pilot, so you have to go to the workshop for nearly all required work. The Diesels are also reducing these cost by avoiding 50h maintenance.
Moreover the operation of modern diesel engines is very simple (single lever operation), which in the end gives more safety in critical situations.
Although you excluded the Contiental diesels from your selection, I would consider to buy a DA40 TDi with the engine close to its end-of-life (which would be a low and very good price) and install a new CD-155. This at least to me is a better solution than the NG.

Reinhard

[Aviathor]

There is a safety report from the French AAIB (BEA) which concludes that the CD engines have about half the rate of in-flight shutdowns as their Avgas counterparts.

https://www.bea.aero/etudes/thielert.ta ... ngines.pdf

[CFIDave]

In reading the report, it appears that Thielert in-flight shutdowns from ALL causes are roughly the same as for avgas engines, i.e., about 10 shutdowns per 100,000 hours of flying.

[Erik]

In reading the report, it appears that Thielert in-flight shutdowns from ALL causes are roughly the same as for avgas engines, i.e., about 10 shutdowns per 100,000 hours of flying.

Wow - that really is a lot which ever type engine we are talking about.

What fraction of those is fuel exhaustion? (I would guess a large fraction).

[Karl]

In reading the report, it appears that Thielert in-flight shutdowns from ALL causes are roughly the same as for avgas engines, i.e., about 10 shutdowns per 100,000 hours of flying.

There is a slight difference in that TAE/Austro engines are FADEC controlled which means every in flight shut down is reported via the data download feedback system to the factory. Only reported Avgas in flight shut downs are recorded, not everyone reports everything.

Also Avgas engines have been around for a very long time and for TAE/Austro to match their safety in such a short time has to be a good point.

[Karl]

Diamond aircraft are demonstrably safest in class. They actually go through car style crash testing. I do not know of any other manufacturer that does so.
It the event of a crash a fire is much less likely with Jet A1 on board than with Avgas.
Yes TAE had a few issues in the early days but they were forging the future. Essentially TAE did the test flying then Austro cloned the engine with a few modifications to overcome issues that had been found by TAE.
I have been maintaining and operating TAE (and now Austro) for 10 years. We were logging 20,000 engine hrs a year. TAE confirmed that we were flying more hours than any other customer.
My experience is that in the last 6 years, when properly maintained the TAE and Austro are more reliable that any of the Avgas engines, require less maintenance and are more fuel efficient.
Due to the FADEC they are more complicated to maintain especially when it comes to fault diagnosis and it is important to choose an experienced engineer.

[CFIDave]

There is a slight difference in that TAE/Austro engines are FADEC controlled which means every in flight shut down is reported via the data download feedback system to the factory.

Please describe how every in-flight shut down is reported via the data download feedback system.

TAE (now Continental) and Austro "wizard" software with the appropriate hardware diagnostic cables exists only at maintenance shops trained in their use, and the engine event recording and log files generated by this software is used mostly by local techs to diagnose and repair engine faults. Files that might indicate an in-flight shutdown get sent back to the Continental or Austro factory -- a manual process of techs emailing the files -- ONLY if the local techs working on these engines want additional help with their diagnoses.

TAE/Austro engines are *not* like some modern cars with built in cellular/WiFi Internet connectivity that automatically exchange log information or diagnostics (or in the case of Tesla, receive new software) with the factory in near realtime.

Therefore the percentage of reported in-flight shut-downs that get reported may be similar between avgas vs. diesel FADEC piston aircraft engines.

[Karl]

Files that might indicate an in-flight shutdown get sent back to the Continental or Austro factory -- a manual process of techs emailing the files -- ONLY if the local techs working on these engines want additional help with their diagnoses.

Hi Dave,

I don't have time right now to look at the Austro manual but as far as TAE are concerned your technician should be sending the data back to the factory EVERY scheduled servicing. Its part of the OEM maintenance requirements.

[Karl]

Hi Dave,

Not sure how to edit my earlier post so have to give an update like this.

I have checked the manuals and can confirm that both Continental Diesel and Austro engines require a data download to be emailed to the factory every 100 flying hours.