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Just a few months ago, my partner and I crossed one year of ownership in our (sometimes) beloved 2023 Diamond DA62. More than a year later, we’re still painfully debugging the airplane.
It’s bittersweet, because this airplane is a joy to fly, it’s statistically one of the safest airplanes ever produced in history, but it’s been plagued with quality control issues from the very first day of delivery until now. To be honest, nothing serious that would’ve affected the safety of flight. At least not yet.
Prior to this airplane, I owned a Cirrus SR20 G6 for just over 4 years. The Cirrus was definitely not trouble free and I had one major incident that did affect the safety of the flight, resulting in an emergency deadstick landing, fortunately uneventful, on a certified runway. Other than that, a couple minor things here and there. In general, the airplane was almost always available and I never hesitated to go anywhere with it in fear of being left stranded somewhere. That’s not the case with the DA62 however. I do hesitate to travel in it. Not for safety reasons at all. I feel a lot safer in it than I ever felt in the Cirrus. But for AOG reasons. I’m always too worried about being stranded, in an airplane that 99% of mechanics don’t know how to fix. That’s a shame, because it’s affecting the utility of the airplane.
Delivery flight
We traveled to Port Huron, Michigan to meet our ferry pilot, who was bringing the airplane from London, Ontario, where it was manufactured, just 61 nm away. On that short flight, we noticed that we couldn’t track the ferry pilot inbound. We later found that the transponder was configured with a different callsign, which got fixed by the service center in KAPA, on our way to California. Minor thing, but some lack of quality control there.
On the flight from KOMA to KAPA, we had a more serious problem. The DA62 has four fuel tanks, consisting of two main wing tanks, where the engines feed from (25 gallons each), and two auxiliary tanks behind the engines (18 gallons each). As the main tanks go lower, fuel from the auxiliary tanks need to be transferred to the main tanks via an electric pump. This operation is done manually by the pilot every 45-60 minutes, but it’s very simple. All tanks have digital gauges integrated in the G1000 panel. On that flight, we noticed we couldn’t transfer from the right auxiliary tank into the right main tank. We immediately decided also not to transfer on the left side, as that would get the airplane unbalanced. We ended up landing in KAPA with 36 gallons of unusable fuel, and the service center there couldn’t fix it. We had to ferry dead fuel weight all the way to California.
We’re very blessed to have a good Diamond service center in our home field KHWD, Absolute Aero. They got the airplane the day after we arrived and found the issue. The auxiliary pump has two sensors that will shut it off. One is when the aux tank itself is empty, so the pump doesn’t run dry. The other one is when the main tank is full, so we don’t pump fuel overboard through the vents. Smart design. The first sensor was damaged, indicating the right aux tank was always empty, preventing the pump from running. That was fixed a couple days later.
This is the tank microswitch. It was mechanically stuck.
Main fuel gauge gone
Just a few weeks after delivery, another problem started showing sporadically:
The right main tank indicator was crossed out yellow, indicating the G1000 isn’t receiving data from the fuel gauge. Even though that sounds like a very simple problem to solve, it absolutely is not. The only way to access the fuel gauge is by removing the entire wing off the airplane. If you remember the FAR 91.205, yes, a fuel gauge is required for flying, so we were AOG.
That was pretty sad. Our brand new airplane had to be disassembled just a couple days after delivery. Diamond was so incompetent during this process that it took them about 2-3 weeks to send the right part. This is the fuel sensor:
Each wing has two of those, one inboard and one outboard. The inboard one failed. Keep reading to learn why it has failed, which is the interesting part.
I happened to be on vacation while the airplane was in the shop. I was on vacation because I wanted to be enjoying the airplane actually, but oh well. Anyway, I had time to be around lurking, then I found something that caught my attention:
The DA62 wing has two wingspars. This picture is one of the cavities where the spar connects to the airframe. That liquid accumulation shouldn’t be there. I asked the mechanic about that and we started investigating. We quickly realized it was TKS (anti-ice fluid). Then we disassembled the faulty fuel gauge:
The gauge was dripping in TKS inside. For those who don’t know, TKS is highly corrosive. It will destroy any metal it touches. It’s also very watery, so it goes very easily through anything that’s not perfectly sealed.
The service center asked the factory why there’s TKS accumulating inside the wing root. In summary, the airplane design has a drain hole there, for that reason. We could see the hole there, after cleaning the mess, but we couldn’t find the other side of the hole underneath. During manufacturing, someone drilled half the hole and never made it to the other side. Now that the airplane is complete, there’s no way to finish that hole. The factory has been promising a solution for that for over a year and still nothing. Only more and more excuses.
The service center installed the new fuel gauge and sealed the sh* out of it. I’ve requested the left wing to be fixed as well, which still hasn’t happened, more than a year later. The fuel sensor there has never failed though.
GPS outage
Around the same time, the GPS started acting up. If you want something to really catch your attention, try losing GPS completely during an RNAV approach over rugged terrain. Yes, that’s what happened. Fortunately, during my WTF seconds, I broke out of the clouds and landed visually.
After some back and forth, a new antenna was installed and the problem never occurred again.
Air conditioning
The DA62 has an electric A/C, which is powered by an additional alternator on the left engine. The A/C unit is installed in the far back of the fuselage with the air vents running overhead. Back in September, we noticed the A/C would run normally for a few minutes, then disarm. Sometimes, we could restart it, but mostly not. This saga has been going on until today and Diamond still doesn’t know what the problem is. They’ve already replaced the alternator, voltage regulator, switch and whatnot. This has been very frustrating.
Different from the Cirrus, the DA62 has no blowing fan. The vents on the panel are just ram air from outside. They are quite nice in flight, but completely useless on the ground. The airplane can get unsafely hot on the ground and there’s not much you can do about it if the A/C isn’t working. At least the doors have little windows, which help if it’s windy.
It’s not allowed to have any doors open with the engines running.
GIA FAN
Back in January, we noticed this:
It was intermittent, only showing on a couple flights, usually during the flight. A couple weeks later, this happened, which really caught our attention:
The single AHRS rebooted itself during flight. That’s quite concerning, because unfortunately, Diamond doesn’t even offer a dual AHRS option. If the single AHRS goes south, the autopilot, flight director and the HSI go with it. Not fun. At least the standby module has been rock solid, powered by its own internal battery.
The GIA fan was replaced a couple weeks ago. No alerts since.
Engine AD
Back in February, Austro published an MSB, followed by an AD, about some screws in the engine that were manufactured outside the specifications. Just a couple weeks before, an unusual number of DA40-NGs suffered catastrophic engine failures. Although Diamond won’t admit, it was quite likely this was the cause.
To comply with the AD, the service center needed to open the oil sump, which required one side of the engine to come out of the mounts. Quite tricky labor to get it done, 15-20 hours per side.
Since we were getting close to the annual inspection and also close to the 300-hour inspection, which required the removal of the props and gearboxes, we decided to do everything at once. The airplane was down for a month or so.
The service was so invasive, that we contracted an experienced DA62 instructor to do the first flight.
Aux pump - again
On my first flight after the annual, I realized the left aux pump wasn’t running. Again, I was stranded with 36 gallons of unusable Jet-A. The problem was diagnosed to be exactly the same we had at delivery, just on the other side. That was fixed recently.
Software updates
Diamond certified the G1000 NXi in a rush, so they left a ton of NXi features left behind, like visual approaches, animated Nexrad and a couple other things. Despite endless promises, they haven’t published a single software update in many years. Features that we’re still waiting for were already available on any Cirrus G6 since 2017.
At least they delivered on one promise, which was the certification of the GWX 75 radar, which is really great. When we ordered the airplane, we insisted we’d only accept the 75 and not the 70, even if that required an installation at a later date, which is what happened. The radar is installed now, but of course not without a lot of drama.
The airplane was pre-wired for the radar at the factory, but for some unknown reason, the ethernet cable was too short and it would never make it to the antenna. After much back and forth, the factory authorized the service center to fabricate an extension.
The radar has been flawless since then. That said, the GWX 8000 (3D volumetric) certification, which is just a software unlock card, is still pending. Supposedly, that will be released with the much-promised NXi software update. We can’t wait for that.
Conclusion
As I said above, the airplane is a joy to fly. It’s incredibly efficient, especially at Jet-A prices. It’s comfortable on long flights and it has a pretty decent performance, given the power available. Once you have some height, flying it single engine is a nonevent. If you have to shut down an engine in flight, it’s extremely unlikely you wouldn’t make it to an airport safely.
Did we regret buying it? I’m not sure. The Cirrus was definitely simpler, but also a bit less capable. And Cirrus has also been a shame supporting the fleet, with chronic lack of parts.
I think we are already at the top of the piston class. From here, the only options are turbine-powered, and that’s a huge jump in expenses, both capital and operational.
Hopefully we’ll finish debugging this airplane, so we can enjoy it for several years to come. The warranty is running out though, as it’s only two years.
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