I never really liked the SR22’s backup instruments. They work, of course, but flying in IMC looking down all the time is very uncomfortable. The “problem” is that older SR22s (except “R9”) have no second AHRS. It is very rare (actually I have not heard about one case) that the AHRS inside the PFD goes bad, it’s almost always the PFD’s screen/backlight that fail. When the backlight fails the AHRS stays operative and the autopilot and all would work. You also have the MFD for navigation and the two GNS430 screens.
But if the complete electrical system fails (Alt1, Bat1 and Alt 2 Bat 2) the screens will go dark.
It’s maybe a bit over the top but a second AHRS/AI felt like a good idea. The Dynon D2 has a very reliable gyro, a GPS and a g-meter, and it can even send the attitude and GPS data to an iPad by Wifi. It comes with a RAM mount, an extra RAM base for the panel and even a holder that can be installed in a normal size instrument hole. The battery lasts minimum 4 hours, and I really never fly in IMC that long, most of the time it’s 30 minutes, longest was 1.5 hours …
The idea is to always switch it on entering IMC and switch it off in VMC. There’s also a USB charging cable, and s 220 V charger.
I installed it on my existing RAM base near the ignition, which i normally used for my iPhone holder or a GoPro camera. With a longer mountin arm it could be even a bit higher.
Flyer59 wrote:
I installed it on my existing RAM base near the ignition
How did you mount the RAM base there?
It’s one of the small RAM bases with two screws. There’s a panel screw in that corner which I used, plus some strong double sided tape. I have not drilled a hole for the second screw (because I was not sure what’s behind there). But it is really strong enough as it is. Once I know that nothing is behind there I might drill a hole and put in one of those screw anchors that can be installed from the front.
Will be happy to hear about your experience with the D2 ,
I’m considering buying it too as a backup AI , but read a different opinion about it’s realiabilty .
Any input will help
Jackob
Hi jak,
i can’t tell anything about reliability, of course, but the D2 worked without a flaw until now.
What i don’t like so much is that it takes a little while until the AI is displayed after switching it on, so I’ll always have it on on flights that go into IMC.
And: the screen is not very bright, especially not with my sunglasses on. But i am sure it’s bright enough in IMC.
More to follow …
Flyer59 , thanks for your input .
It looks like you found the perfect location . No problem with Gps reception ?
What about calibration ? Do you have to calibrate it every flight ? how long Does it take?
Jackob
I have got a D1 and fully agree. It’s a very good back up instrument.
Your installation has given me just the idea I needed to make mine a permanent part of my panel too.
Re charging, in theory it could just be connected to the airplane 12 V system via the charger cable it has, so if the power fails it will run for 4 hours thereafter.
The D2 has some very interesting additional features, I fully agree. What I wish for is to be able to select the speed and alt strips off if I want to, in order to use it as a pure gyro, as the speed in particular can be massively misleading if it is inadvertendly used as a PFD.
I also have a D2 and mount it as shown. It works reasonably well, calibration takes only a few clicks with the dial-knob, but readability in bright sunlight is an issue IME.
Yes, i think so too …. but then I will probably never need it in bright sunlight :-) Should be ok in IMC.
I have stored the USB charging cable in the plane.
I confirm that calibration only takes some clicks, and it also stays calibrated. The integrated g-meter on the second page is nice.
GPS reception is no issue for my installation, i don’t need the external antenna. If you install it in a standard instrument hole (that holder is in the box too) you might want to use the external antenna.
blueline , nice panel and location too .
As I see it the main issue in emergency is to know you are in that situation . Once you realize it , it’s much simpler to act .
Having this display in front of you makes it easier to understand your situation and to act faster
I have Garmin 795 and considered to add GDL 39 3D for EFIS or a separate display with the dynon D2
