However, recently I spoke with a friend who was a CFII on an
airport with a 912 in a Diamond Katana used on that airport for instruction.
He condemned the engine, said it (and a few others at other nearby airports)
were often in the shop for repairs, and says he's sure that's the big
reason -- service dependability problems -- why Diamond dropped the 912 as
a powerplant and went to Continental and Lycoming.

I am a CFI A,G and an A&P with an I.A.
I was a Field Service Rep. for Diamond for over a year. I received formal
training on the Rotax engines during this time.
I fly and maintain the Rotax 912 and 914, but have only flown the 912S.

Diamond uses the Lycoming in the DA40. Rotax does not make an engine powerful
enough for this aircraft.

Problems with the Rotax engines included
1. Both Rotax and Diamond did a poor job of educating mechanics on how to
maintain the engine and pilots on how to operate the engine. Pilots are
generally not very knowledgeable on engine operation. As proof I offer all the
"old wife's tales" seen even on this newsgroup.
2. The Diamond engine installation is less than ideal. "10 pounds in a 5 pound
bag".
3. A&P mechanics were not overly interested in learning something new, liquid
and air cooled, electronic ignition and in metric too.
4. The Rotax maintenance manuals are not well organised. However they are
available on line for free, as are SBs.

Some of the operators I served loved the engine and had no problems maintaining
them. These folks knew the engine frontwards and backwards. They took the time
to educate themselves.

I must admit it took me a bit of time to learn the engine but the information
is available if you care to look and ask questions. When the engine is set up
correctly, it starts like a car, hums like a Singer sewing machine and produces
rated power.

Lockwood is a good source of information, as I am sure CPS is. Lockwood seems
to be able to get me parts literally over night. I guess it is not hard to
stock parts when there are only 3 models. Diamond still supports the Rotax
powered airframes, and the two Field Service Reps, (Paul and Glen) do a great
job of answering questions.

One of the Rotax powered aircraft I maintain is a Katana DA20 A1 with a 912.
The owners lease it to a very active flying club for student training. The
owners are very happy with it and the students fly it a lot.

Another is a Katana Extreme motorglider with the 914 turbo in it. The biggest
problem with this is the waste gate shaft rusting in place because of the lack
of usage. Otherwise the engine runs great.

I change oil every 50 hrs and leave spark plugs in no more than 150 hrs. The
engine wants to be operated a lot, fly it regularly. Maintain it by the book.
At operators where problems are occurring I'll bet none of the A&Ps have formal
training on the Rotax engine and have not really read the book.

My biggest complaint is that with such a modern engine with electronic
ignition, close tolerances, high revs,a gear box, why in the world does it
have carburetors. Why not fuel injection?

It is not a Lycoming or a Contintal and can not be treated as one. Many of the
problems I saw were a direct result of lack of maintaince or operating well
past the recommended service times. It is a bit odd isn't it that this engine
has found acceptance in the rest of the world? It seems that just here in the
US there have been so many problems.

I have flown Rotax powered aircraft in good WX and bad, night and day. I'll
continue to fly ones I maintain knowing they will do good by me.

Robert Mudd