GRT Avionics

I'm trying to decide which options to get on the Horizon 10.1 and have an IFR GPS NAvigator (GNZ 375). As a result, I don't see a good reason to get the internal IFR option. Perhaps as a backup...? Interested in different viewpoints. Currently have a 2 HX EFIS installation, but one EFIS is becoming less reliable.

Thanks in advance,

My opinion would be, save your money.
GRT clearly notes that the internal option is legal only during vfr operations. I think grt hoped that this unit would receive the same treatment from the faa that they gave to ADSB position sources: ‘Must meet the performance standards of the applicable TSO, but does not have to actually have a TSO.’ However, so far, there has been zero movement by the faa. Which is a shame.

Thanks Bob!
I agree, it is a shame.

I've got the IFR Approach option and find it works great, particularly in conjuncture with the autopilot. Even if you aren't using it for flying the approaches (assuming you connect your A/P to a TSO GPS and use that to fly the approach or something similar) it should be useful to support having the approach in your flight plan for ETA calcs and to display approach plates etc.
Either way I also approach it with the understanding that for IFR one needs "Two-way radio communication and navigation equipment suitable for the route to be flown." and that experimental aircraft can and regularly do use non TSO equipment such as CDI, HSI, AI, etc, so why not GPS? A lot of people seem to think that GPS is some magical mystery box so unlike a simple CDI/HSI connected to a VOR/GS that they insist on getting a TSO part. If that makes you more comfortable, go for it.

The big question here, I think, is whether you plan to actually fly a lot of IFR flights. If so, you probably have a Garmin or Avidyne Navigator already.

If you have the navigator, then you will want to be very PROFICIENT with it. It will become the way you enter flight plans and do approaches.

Now if you are more casual and just want the practice so that you have an EMERGENCY out (you get to be alive to fill out the FAA paperwork IF needed) the the GRT approach is nice . It is integrated into the GRT user interface and architecture.

I have both on my plane and as I get more serious about get BACK to being proficient and current, I am trying to use ONLY the NAVIGATOR that I have.

Given the IFR that I have flown so far, and given the current ADS-B options, I could have saved a LOT of $$$ on my RV6 and RV8 by going with JUST the GRT stuff.

This is meant as a reply to webutler, and I apologize for its length. A little history: Decades ago, nav receivers in part 91 operations had no TSO requirements. The FAA was more laisez-faire. Indeed, King rather famously sold two nearly identical DMEs, one more expensive and TSO’d, the other with no TSO. Owners who were sure they would never sub-let bought the non TSO boxes, while those who planned to sublet to the local FBO, which wanted to use the plane in non part 91 air taxi operations, needed the TSO’d box. (For the same reason most nav receivers did have a TSO - it wasn’t that hard or expensive to get). Now, move forward to the later 1980’s. The FAA has decided more regulation is good. It’s too late to do anything about nav receivers, but with gps just coming available, they explicitly wrote a TSO requirement into the part 91 (ifr) regulations for gps use. Some years later, they softened it a bit to ‘approved gps’ and you need to look at 14CFR part 1 to find the definition of ‘approved’, which says, in legalese, that a TSO is one form of approval, but the faa may issue other forms of approval. The faa has used this authority to approve non-TSO’d gps for use in ADSB systems, as long as the manufacturer states that it meets the ‘performance specs’ of the TSO. So the problem is that the FAA has, so far, declined to issue any option other than a full TSO, for ifr use of gps. I suspect GRT was hoping to get lots of (vfr) data reports from its users, and submit that to the faa and ask for a ‘meets the performance spec’ approval. But so far that hasn’t happened.