IFR Solution for Experimentals......

Matthew (FWP149D)

Filing Flight Plan
May 5, 2016
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Matthew (FWP149D)
All, I asked the following of Garmin:

"Can I pair the TSO's GTX345 (with WAAS GPS) to my G3X and be good for IFR flights? If the GTX345's TSO's WAAS GPS positioning is being fed to the G3X, then I would think I would be good for IFR navigation."

I got this response:

"I understand your line of thinking, but unfortunately, sending the ADS-B approved WAAS GPS position information does not upgrade the G3X into an IFR certified navigator.

We would still need something like a GTN or GNS WAAS unit to fly IFR. When a certified navigator is connected to the G3X, it is only displaying the certified devices information, not generating the information on its own. Connecting an IFR approved device does not upgrade or unlock the G3X making it IFR certified.

There are a lot of requirements from the FAA to make a navigation device IFR certified."

However, I believe this is true:

Per my research and communications with various FAA experts, GPS equipment must meet the performance requirements of the applicable TSOs, but there is no specific requirement for the equipment to be built under a TSO authorization (specifically the G3X). If the equipment is not built under a TSO authorization, it is up to the owner/operator to verify and document that the equipment performs within the required specifications. It is also the owner or operator's responsibility to document the necessary flight-test data showing that the installation performs within the required accuracy parameters. I would expect that a G3X paired with the GTX345 would be clearly accurate enough that I could document the necessary flight-test data needed. I know that Garmin wouldn't suggest this course of action but I do believe it would be legal to operate.


Does anyone have a different take on the situation?


Most of the stuff in an experimental plane only needs to meet TSO specs. Unfortunately, if you want to do GPS navigation while flying IFR you have to have a TSO'd GPS approved for IFR by the FAA.

I'll see if I can find a note from the EAA concerning that.
I got the idea after reading this article from EAA:
Found it! (I'm a data hoarder. I need help!)

Anyway, this document was created in 2002. I'm sure it may have been updated by now, especially since there are now GPS units that can used without ground based navigation.

Unless you're hell bent on installing the avionics yourself, you may want to get with a shop that specializes in experimental panels and design a panel with their help.

EDIT: Looks like I was slow with my PDF. I'll leave it here for others.


  • IFR equipment.pdf
    14.7 KB · Views: 25