Owner maintenance / limitations DA42NG

[michael.g.miller]

I am looking at buying a DA42-NG, having previously flown an SR22. I'm a part 91 operator who is used to doing his own oil changes. I know the DA42 has some 100/300/600 hour service intervals. I'm curious:

- Which of these intervals can be done by the owner under part 91? Can I do the 100h oil change without mechanic oversight? (Obviously having a mechanic supervise me the first few times)
- What are the requirements for continued airworthiness under part 91? Am I required to do the 100/300/600 hour inspections?
- From a practical perspective, do people abide strictly by the hourly recommendations? Or do owners generally favor a more condition-based approach?

Thanks!
Mike

[Rich]

In the US, see FAR Part 43, Appendix A.

[Rich]

My previous post only covers what you are permitted to do. If you look carefully at the list in this appendix, you'll see not much about the engine itself is permitted. Oil changes are one of the permitted activities.

We go round and round about the mandatory and non-mandatory parts of the maintenance manual. So don't expect anything definitive. As for me, since I'm now the only one flying my plane and never hit 100 hours in a year, I just get everything at annual.

[ultraturtle]

The 100 hr maintenance event might better be described as a "service" because it is not just a simple oil change. It includes a lot:

• Check Engine Harness and Sensors
  Check EECU (fault code memory)
  Check EECU read out
  Check Gearbox Oil
  Check Gearbox Oil Filter
  Check V-Ribbed Belt
  Change Engine Oil
  Change Engine Oil Filter
  Check Cylinder Head Drain
  Check Fuel System
  Change Fuel Filter
  Check Waste Gate Controller
  Check Exhaust System
  Check Cooling System
  Check Oil Seperator Breather line
  Zonal Inspection

That said, yes you can technically do all but the EECU fault code memory and EECU read out by yourself (unless you are "Dongle-Worthy"), but would certainly need some training and supervision by a mechanic certified to service Austro Engines.

There are dozens of opinions on this forum as to whether or not you should accomplish all Chapter 5 stuff at every 100 hr interval when operating Part 91, not making money off of the aircraft. I personally do it all, but that's largely because I've invested some time and effort learning how.

One highly recommended option that any Diamond owner should take advantage of is to attend the Diamond/Austro Maintenance course at the London, Ontario factory. One course is free for either a new owner or his designated mechanic, and the cost for others is quite reasonable. I attended the course (as did CFIDave) and found it to be one of the most satisfying 5 day schools of my life. One bonus is that it elevates you to the status of "Dongle-Worthy", meaning that it gives you authorization to purchase the dongle to download the EECU read out and fault code memory of the Austro engines, and establish an account to access all of the double secret Austro maintenance documents.

Just did my first mechanic supervised 100 hr service, and look forward to my first solo 100 hr service sometime next year. CFIDave has done a lot of them and has posted a bunch of relevant information on this forum. Suggest you search his posts.

[CFIDave]

I agree with everything Rob said above about the ability of owners to perform their own 100 hour servicing on Austro engined Diamonds, but thought I'd add a bit more information.

The first couple of times you do this yourself, I suggest you order Diamond's 100 hour kit that includes all the parts needed to perform the service with the exception of the MAN fuel filter that must be ordered separately. Later you can figure out where to find alternate sources for most parts and fluids to save yourself some money. You're really servicing a Mercedes car engine, so Diamond will send you a genuine Mercedes oil filter in their kit. In the US, you can even obtain Castrol "European formula" synthetic oil off the shelf at some Wal-Marts -- as one of the Austro-approved engine oils. And I prefer to use Blackstone for oil analysis here in the US, rather than sending oil samples all the way to Austro in Austria. (Sampling bottles and oil analysis by Austro is included with the 100 hour kits, but they never get back to you unless they find something irregular.)

You'll need to practice your safety-wiring: it's helpful to take photos of existing wiring before you start cutting wires.

My new DA42-VI back in 2013 did NOT come from the factory with quick drains on the oil pans, which made draining engine oil really difficult and messy (you've only got a limited amount of space to get your hands between the drain plug and the engine radiator located underneath). But in 2014 once Diamond approved quick drains that could be installed on Austro engines, changing the oil became MUCH easier -- I simply hook up some short length rubber hoses to the nipples on the end of the quick drains and send the used oil right into plastic gallon milk cartons. (My new 2017 DA62 engines came equipped with these quick drains.) And replacing the oil filter (a paper insert) is much easier than on a Lycoming, since the Austro/Mercedes filter is located right on top of the engine.

Expect to spend at least a full day for the 100 hour servicing on a Diamond twin.

With regards to the Austro Engine USB "dongle" for using laptop Wizard software for engine fault diagnosis, new software uploads, etc. -- presumably the shop you use for your plane's annual inspection will run this for you at annual. But it's great to have the training to be able to operate the Wizard -- I like to use it not only on my plane, but to help out other Diamond owners.

One additional benefit of taking the Diamond 5-day training class worth mentioning: I had an alternator failure occur when flying my DA42-VI out in California back when it was still under warranty. The good news is that I managed to land at a Diamond Service Center FBO. But back in 2014 that service center was only trained on Thielert/Continental diesels. Since they hadn't been trained on Austro engines, the Canada factory refused to ship them a new alternator to install in my plane. However, once they discovered that the owner (me) had been through Diamond's 5-day training class, they shipped the alternator with me "supervising."