EFIS-D10A STC Usage

[JohnAJohnson]

My Cessna has steam gauges, and will eventually have a Skyview system when the 177RG gets added to the AML.  When that happens, I'd like to have three independent attitude displays - the Skyview, and two D10As.

While I'm waiting for the STC, I'll install an Avidyne IFD540 and would like to install a D10A in the pilot's periphery to use as a Nav Head/HSI for the Avidyne.  There is no suitable CDI or HSI in the plane right now, so I'd have to purchase a GI-106, G5 (HSI STC), D10A, or some other solution to legally navigate off the Avidyne.  It appears the D10A has lots more capabilities than either Garmin solution and for less money.  And once the Skyview STC is approved, the plan would be to move this D10A to the Copilot's panel, used as the third attitude display.

Couple of questions...

Is what I propose doable and does it sound like the best option?

- I'll have one antenna (Garmin GA35) for the Avidyne, another for the 10" Skyview, and two more for each D10A, for a total of four GPS antennas.  Is that correct?  Must all three Dynon EFIS units have their own antenna?  Same question for magnetometers, and battery backups.

- Is it common to run three EFIS units off one pitot static system, or is it wise to add another probe for redundancy?

Thanks,
John Johnson, Gulf Shores, AL

 

[Dynon]

So there are few things here. First, know that although the EAA EFIS-D10A allows the product to be installed as either a primary or backup attitude indicator, the HSI is not usable because the EFIS cannot be connected to any external navigation device in certified installations. So while the product technically has the capability, it unfortunately can't be employed in this situation (they CAN be connected to your eventual SkyView HDX installation). So although we'd love to sell you an EFIS-D10A before you do your more complete panel upgrade, it may not be the best solution for your mission as an HSI.

On GPS antennas: For an EAA STC'd EFIS-D10A you must use the GPS-251. But for an EFIS-D10A that goes in with a SkyView HDX STC, you do not connect a GPS antenna at all. There are some deep technical reasons why, but it really comes down to redundancy and backup requirements in failure cases in the mission of the device, which is different for the EAA EFIS-D10A (primary attitude indication) and the SkyView STC (the D10A is backup).

The magnetometer is an option for the EAA STC, but is not an option and is not installed for the SkyView STC. SkyView has its own magnetometer that must be installed.

Batteries are required for all STC'd displays (both variants of EFIS-D10A and SkyView HDX displays)

It's common in light aircraft to only have one pitot/static system for multiple EFISes. Adding different sources in a type certificated aircraft would actually require some kind of approval for such a modification.

 

[JohnAJohnson]

Thank you for the prompt and concise reply. I guess my only path would be to find a cheap CDI to use with the IFD540 for now. I'd consider a G5, and would plan to use it as the third attitude display with the Skyview/D10A package, but the G5, as best as I can tell, must be purchased as attitude or HSI, and once you have it, you can't change it to the other. Sure wish you guys would produce an STC'd HSI using the D10A.

 

[Raymo]

Once you have the Skyview HDX, it can be used for the HSI, connected through an ARINC-429 to the IFD540.

 

[JohnAJohnson]

Thanks Ray. Do you know, once the STC Skyview (and backup D10A) system is installed, can the backup D10A also be used as a nav head/HSI for installed nav radios (my IFD540 and one other TBD radio)?

 

[Dynon]

Unfortunately not. The D10A's in either scenario can not be connected to navigation devices. They're PFD/attitude only.