Recommendations on Diamond Certified shops

[A Dopo]

I know this sounds like a rant. I hate annuals with a passion, last two annuals have had unbelievable issues with shop(s). Things that happened where very stupid and inexcusable, inattention to detail etc. What these shops do is so important as a small mistake can be fatal, and you cannot just pull over on the side of the road. Nothing life threatening happened, but just dumb things that should not have happened like frying the ECUs because they wired the auxiliary plug backwards when they did something to the AC, and the other shop got overspray on the wings, and melted our first gen Jet shade when they left it out in the sun when they assured me it would be in a hanger. I found out about the jet shade issue when I called the factory to find out why it had delaminated. Yes, I know you would think they are designed to keep heat out, but the first gen jet shades had issues that were unknown to us as we always hangar the plane even when traveling or cover with the Bruce cover. We had these since 2019 and this just happened.

So in a year another invasive annual will take place, taking the joy out of ownership. Where are the best Dimond certified ships within a reasonable distance to South Carolina and what have your experiences been in general with your annuals? That is the one issue with the Diamond, especially the Diesel as there are limited shops "qualified" to service these.

I hate annuals and have found that you cannot always trust what they are doing. Same thing happened when we owned the best 172 in the world. They cracked the trim wheel plastic cover, and more importantly failed to put the nut back in that kept the seat from sliding backwards upon take off and landing. The lawsuit that followed from that fatality almost killed Cessna. This seat sliding issue was simply a "seat belt fix" under the seat that attached to the seat frame and would keep the seat from moving. I think a number of bad accidents and fatalities have been attributed to this sliding seat that was not secured properly.

Can someone invent the Work Cam that records all actions for me? These would be placed in strategic locations and include voice, sound. It would also record hours of "movement" etc. You could use AI to summarize the Annual and look for mistakes. You are welcome for the multimillion dollar idea if it has not been invented and perfected.

Parting thought, we love the NG, not so much the experience with the Annuals. However, due to past experiences, I dread all annuals. It's a place to get nicks, scratches, and worse.....could it save your life? Sure, but the experience alone may kill you.

[Steve]

Juan - I can sympathize with your frustration, although I haven't experienced similar issues with my (now up to 22) Annual Inspections. I have always done owner-assisted Annual Inspections, in my hangar, with an A&P/IA on my home field. I attended the Diamond Maintenance Course twice in London, have always been a gear-head, and worked as a machinist Summers during college. Which is to say that I am comfortable with tools and around complex machines. Granted, I completely avoid some of your issues because my airplane is a -180, not an -NG.

I also like the idea of two sets of eyes examining everything (mine and the IA). We use the inspection checklist in Diamond's AMM. I fly about 75 hours per year, and have always wondered about the risk of maintenance-, or inspection- induced issues. There is a good article by Mike Busch in the November, 2025 issue of AOPA Pilot discussing this very issue. I agree with him that for many GA aircraft, it might be safer (cheaper, more efficient) to require inspections every 300 hours / 24 months.

[dmloftus]

Hi Juan,
Were your issues with the DSC shop in Greenville, SC or the one in Salisbury, NC? I have had pretty good luck with NC shop, although I have experienced a few unforced errors. One year I flew home to Atlanta only to find that they had reinstalled my nose wheel backwards and I could not get to the tire valve without removing the wheel pant. Another year I had my original lights/strobes replaced with LED lights, but I was surprised that they installed red and green wingtips in reverse (green on port side).

[blsewardjr]

I've been happy with Dillon's Aviation in Greenville, North Carolina -- https://www.dillonsaviation.com/ I go to them from Virginia for specialized Diamond work. They run a flight school full of Diamonds so lots of experience.

[Eastbayavi]

Everybody has issues with the diamond certified shops. My question is do we really need to go to one for the lycoming da40 when this plane and engine is supposed to be ridiculously safe and idiot proof.

[blsewardjr]

I've used a DSC for issues specific to Diamonds such as the Major Structural Inspection and the bonding system inspection, and any repairs necessary as a result. I also like a different set of eyes on my aircraft so I do annuals with Dillon's every 3-4 years.

[jwx96]

While we’re on the subject, I wouldn't mind a recommendation for a shop/mechanic in the Minnesota-Wisconsin-Illinois area. I live in Minneapolis but used to fly to Illinois for my annual. This year’s annual was in Minneapolis, but I don’t think I’ve found my maintenance home yet. Has anyone been to JA at KARR? I also need a new engine (Lycoming) installed in 12/2026. Thanks.

[Johnrschaefer]

Everybody has issues with the diamond certified shops. My question is do we really need to go to one for the lycoming da40 when this plane and engine is supposed to be ridiculously safe and idiot proof.

My single experience with a Diamond certified shop for annual was VASTLY more $$$ than any other - at least 4X my typical annual. In fairness, there were a couple of costly one-time items, but even excluding those the invoice would have been jarring.

I've been quite happy with a non-Diamond-certified shop for most of my (Lycoming DA40) annuals and some intervening maintenance, and will use the same non certified shop again for this years annual. Full disclosure, they "used to be" certified. I mentioned this to someone at the Diamond factory (DiamondFest!) last September, and they seemed to have no real concern about the non-certified shop. I understand this may be different for the NGs etc.

Nothing in the foregoing remarks should be construed as advice, suggestion or any manner of guidance - just relating personal experience.

[A Dopo]

Hi Juan,
Were your issues with the DSC shop in Greenville, SC or the one in Salisbury, NC? I have had pretty good luck with NC shop, although I have experienced a few unforced errors. One year I flew home to Atlanta only to find that they had reinstalled my nose wheel backwards and I could not get to the tire valve without removing the wheel pant. Another year I had my original lights/strobes replaced with LED lights, but I was surprised that they installed red and green wingtips in reverse (green on port side).

Both shops. We were so happy to have a shop in Greenville as it is close to us, but then we got the call that they had fried the ECU. They owned up to it for which I give them credit, but after the repair, and being out of service while the ECUs were programmed at Diamond and installed, they still sent us a bill for the annual. These guys had an unfortunate for them and their customers event that also was unbelievable. Their hangar burned to the ground taking a jet, and other aircraft with the fire. I think I was told they were curing something with heat lamps overnight and an extension cord overheated. Don’t hold me to that but I think that is what happened. You are only as good as the people you hire, and let’s face it hiring and certain employees can really suck. But for all I I know the fire could have been totally on the equipment and not an employee. We lost an amazing house, a mid century organic masterpiece because I was afraid of fire while we traveled abroad. At the last minute one of my wife’s managers volunteered to stay and house sit. He left a three dollar light on I told him not to use on for two weeks and burned the house. People do stupid things, to error is human, is that the saying? House still stands, but needs to be repurposed to a commercial residential Developement. Any developers here? House plus 70 acres on a fast growing interchange on a major interstate hwy.

[Joey]

I have also used Dillon's Aviation in Greenville NC and have been pleased with their workmanship and pricing. I have been using them for the life of the airframe since 2008.