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Old 12-20-2009, 10:33 AM
Mike D's Avatar
Mike D Mike D is offline
Join Date: Jul 2008
Location: Houston, TX
Posts: 453
Default Choosing an EFIS?? - Dynon, GRT, Advanced, MGL?

Choosing an EFIS??

Oh, the endless debate over which EFIS. And with all the great systems out there, the manufactures arenít making it easy on us homebuilders.

Just for background; I have read many of the posts here at VAF and other sites on EFISís. I have seen each system in action at Oshkosh and in planes, but I have only flown behind the GRT, and for only less than 5 hours.

Noting the date on the articles I am reading has become very important because things are changing very rapidly in the EFIS world. All Dynon comparisons have to be noted as pre and post Skyview. And I believe Dynon has now included GPS and pitot data in the attitude calculations which has made some posts (and opinions) invalid. (or am I wrong here?)

With all that out of the way, I have noted a few opinions as to how to choose an EFIS. (Paul had a good post on this.
Given that all the systems are reliable, and that the companies show no signs of disappearing, Some of the differences in the systems I have seen are (read as deciding factors):
  1. The mission - Buy the one that fits YOUR mission and be honest with yourself what that mission is. (Are you really IFR? Iím not now but plan to be by next year. Do you need an auto pilot?)
  2. IFR or VFR - GRT = IFR/VFR mission. Dynon, Advanced, and MGL = VFR missions. My understanding is that this is due to the way each system determines attitude and corrects for errors.
  3. Budget
I have asked many pilots, ďWhat was the determining factor in why you chose the system you have?Ē What this has revealed is that many pilots go with their gut and that I donít know much about EFISís. Both make it hard for me to choose.

I have heard the lite IFR/Hard IFR comments. But I am of the mindset that either you are in it or not. BUT, There were many pilots flying IFR way before EFISís ever came into being. So, I am still a little confused as to why GRT is IFR and why Dynon is not. (especially the Skyview)

Price is always a factor, and that is why I would never even consider a Garmin.

So, on to the questions I have;
  1. Why is a system considered to be IFR, or why not? Please compare the latest data. I am hoping Dynon Support can chime in here as well as others. Are we holding on to old opinions or over equipping our needs?
  2. Synthetic vision is a $1K or more option, is it worth it?
  3. Is there a way to pigon hole the systems (Dynon, GRT, Advanced, MGL) into a mission? - Stein? Paul? DFlyer? Rainier? Anybody?
Given I will drop $5K to $8K for an EFIS, this is no light decision.

It is very hard to overlook all the great features in each system but if pushed, what I personally donít like about some systems are the membrane switches of the MGL (donít mind the connectors but locking connectors would be better), the looks and integration of the EMS on the GRT, the proprietary and completely integrated auto pilot of Dynon, and I have to admit I just know much about the Advanced.

Some of the best things are the trade in program for GRT and the Dynon value.

BTW, My mission is long X-country 3-4 times a year, burger runs every weekend, and some lite acro whenever the wife is not in the right seat.

Enough rambling for me. Any thoughts or answers?
Michael Delpier
RV6A -O-320, fixed pitch, GRT Sport, 496
RV-10 - working on finish kit
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Old 12-20-2009, 12:03 PM
noelf noelf is offline
Join Date: Nov 2007
Location: Cary, N.C.
Posts: 1,119
Default My suggestion... that the EFIS and Engine Monitor solution should be from the same vendor. Not that you can't mix-n-match, but when it comes times for the s/w updates, it is much easier to just have one company to deal with.
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Old 12-20-2009, 12:24 PM
RV8R999 RV8R999 is offline
Join Date: Dec 2008
Location: na
Posts: 1,457

You are exactly correct in being confused by the IFR/VFR debate..

Considering all you need to fly IFR (what is hard IFR anyway?) is to be rated (i dont think three is a hard IFR rating yet?) and have all the equipment listed in Part 91 installed and tested. That is ALL. Each of manufacturers listed have systems suitable for IFR. The pitot debate with respect to Dynon is ridiculous considering the very low probability of a PITOT failure (but they've fixed this anyway with GPS b/u).

What I think most are getting wrapped around the axle with doesn't have anything to do with IFR but rather IMC which are not synonymous. I'd fly anytime, anywhere IFR under VMC without a lot of redundancies. For IMC flight (which requires you to fly IFR..except at sea out of the ADIZ ) I'd like to have at least a B/U attitude reference. In my case I have both Skyview and a D10A. All the other EFIS are equally suitable but the choice is personal more than technical IMHO.
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Old 12-20-2009, 12:25 PM
ken28117 ken28117 is offline
Join Date: Oct 2009
Location: Charlotte, NC
Posts: 25

Michael...i am still building my 7a so I have quite a way before I have to decide.....but as a pilot who likes to fly hard are my thoughts;

Nothing is more important than a good auto pilot....altitude hold a must....capable of vertical nav.... with a 430 or 530 WAAS.


Redundancy ....if your going to have a battery back up...have two. AHARDS...two. if you can have two complete separate circuits (I think they call that dual Buss) DO!!!

All I can say is that when your in the clouds....Situational awareness, being able to keep the blue side up...has no price tag.

I will probably use stein....considering AFS & GRT (not Dynon because every time I call them I have to get a call back) and service is everything.
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Old 12-20-2009, 01:23 PM
jeff beckley jeff beckley is offline
Join Date: Jan 2006
Posts: 192
Default TruTrak EFIS?

Mike keep in mind that in order to fly any IFR you will need navigation radios proper for the flight intended. SL30 if only wanting to do ILS or vor approaches or a 430W if you want all the bells like LNAV/VNAV and GPS approaches. That is to be legal. Also I got tired of having to program three GPS's.

I noticed you did not include the TruTrak EFIS in your searches. I consider it a formidable player in the EFIS Autopilot game. I have been flying behind one for several months now and I am extremely happy with the performance. The EFIS does not have a moving map like the others you mentioned but what sets it apart is the Rock solid performance of the Autopilot and really well design screen. For me the map was not an issue as my 430W provides that and I also have a 396 mounted in my panel for additional mapping and XM weather.

Before I had the Trutrak efis I had a Blue Mountain G4. It had synthetic display, flight planing and other features. The synthetic was cool at first but soon found I had less of a need for it over the meat and potatoes items needed for IFR. For that it was unreliable and not safe.

I looked at the GRT, Advanced, Dynon and Trutrak. GRT was at the top of my list but I did not want an EFIS that has sub menus and was pretty complicated. Advanced was a really nice system as well but still more complicated to operate in IFR than I wanted. Both of them have the ability to interconnect to the 430W for approaches. I found Dynon to be too much of an entry level system with an AP that is still needs time to mature. Even the SkyView is pretty much eye candy and probably never will be regarded as a top notch IFR platform. Talk to anyone that has an IFR ticket and ask if they would fly behind a Dynon AP. GRT and Advanced both use servos from Trutrak I think.

Anyway I ended up choosing the Trutrak EFIS because I found the design to be logical. No sub menus, Super clean screen with just the right amount of data displayed. It is designed to be a flight director that partners with the pilot to control and enhance all types of flying you will do. It operates with almost artificial intelligence that anticipates what commands you might need next and offering that to be selected with the buttons so you will never need to hunt through a bunch of sub menus. The screen layout allows for instant interpretation the info. There is a very nice female voice annunciation that inform you of anything that is important for safety. Like when you lose GPS signal, when you arrive at your assigned alt, low airspeed, all approach modes and any improper situations while on the approach if you might be looking some where else. Just to name a few.
The auto pilot is on par with their top of the line Sorcerer. Provides GPSS steering, LPV vertical guidance, Altitude preselect, Vertical speed, Auto pitch trim. Everything that the Sorcerer does including fully coupled ILS approaches. It even does a nice job of flying the missed approach procedure. It has a separate button that when pressed will engage the AP in pitch and roll. If you find yourself in the clouds and need help you just press this button and relax. Even if the plane is not level. Simply twist the heading knob 180 deg and the plane will fly out. Very cool feature!

The EFIS AP/4 now has full integration with the GNS430W. It displays the ILS/LOC and VOR needles using the new AIRINC converter and as of this week and personally flown several times FULLY coupled ILS capability. Their web site is soon to be reflecting this.

So it depend on what you want out of an EFIS. Day time VFR and no 430 or SL30 I would choose the SkyView. Day and night and a couple Xcountry with occasional IFR with pretty high personal minimums and a 430W/ SL30 I have no problem with GRT or Advance.
Looking for a EFIS with an AP that you would bet your mothers life on then it would be the Trutrak.
Also for what is is worth. The Trutrak EFIS is fully mature with all the proposed, promised, slated, expected features working now. Who else can say that?
Jeff Beckley
Des Moines Iowa
Van's RV-7A
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Old 12-20-2009, 02:26 PM
Danny7 Danny7 is offline
Join Date: May 2008
Location: central oregon
Posts: 1,089

Originally Posted by Mike D View Post
  1. The mission - Buy the one that fits YOUR mission and be honest with yourself what that mission is. (Are you really IFR? I’m not now but plan to be by next year. Do you need an auto pilot?)
  2. IFR or VFR - GRT = IFR/VFR mission. Dynon, Advanced, and MGL = VFR missions. My understanding is that this is due to the way each system determines attitude and corrects for errors.
  3. Budget

I haven't heard it said explicitly, but i'm pretty sure Rob Hickman says he flys IFR behind his panel with all AFS stuff.
edit- thread link :

first post in the AFS synthetic vision thread.
nothing special here...

Last edited by Danny7 : 12-20-2009 at 02:29 PM.
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Old 12-20-2009, 06:26 PM
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Ironflight Ironflight is offline
VAF Moderator / Line Boy
Join Date: Jan 2005
Location: Dayton, NV
Posts: 11,876


I think that you have gotten most of the considerations into your head, and a couple of important points especially - the fat that the market is dynamic, with new features and equipment all the time, and the recognition that what constitutes IFR and VFR is fuzzy - period!

I used to be happy flying six-pack low-end singles with vacuum pumps in the clouds, because that is what we had - and ALL we had. That was light GA IFR 20 years ago. Just about anything out there today for the experimental market is better than that!

The fact that the market is dynamic makes it incorrect to simply refer to "Dynon" - they are bringing out an entirely new generation of equipment, and while I think it still has to prove itself in the field for a period of time, if we simply refer to "Dynon" in threads, we'll confuse the next generation. When I refer to their new stuff, it will be "Skyview", to differentiate.

One thing I am not sure I agree with in your original post is the statement "Assume that they are all equally reliable..." My experience is that some systems are more reliable than others - still. You can level the playing field with dis-similar redundancy, and I personally design systems that way.

Everyone is going to have their own opinions on what constitutes a system's readiness for IFR - personally, I think that I look at the amount of pre-processed information the system gives th pilot - in other words, how much burden does it take off the Organic CPU in the cockpit? Information integration is important - I like a system that gives me all the answers before I have to speak the questions. And the questions I frequently have asked over the years are things like "What are the winds doing to my ability to make my destination with the fuel available? What are my reasonable alternatives if the weather goes to poo? where am I relative to all of the relative navigation points that are important to my right now?" I like systems that make me a smarter and better informed pilot, because it allows me to monitor the flight rather than just keep things upright and pointed in the right direction.

If getting the "Right Answer" to the question "what is the best IFR EFIS" was as simple as posting the question here, we'd all be flying the same thing. Unfortunately, every pilot and situation is different. I have helped a lot of people choose panel equipment, and the answers are frequently different. Know your questions, read everything you can find, answer your questions and make an informed decision right for you.

Paul F. Dye
Editor at Large - KITPLANES Magazine
RV-8 - N188PD - "Valkyrie"
RV-6 (By Marriage) - N164MS - "Mikey"
RV-3B - N13PL - "Tsamsiyu"
A&P, EAA Tech Counselor/Flight Advisor
Dayton Valley Airpark (A34)

Last edited by Ironflight : 12-20-2009 at 08:15 PM.
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Old 12-20-2009, 06:57 PM
bizjet bizjet is offline
Join Date: Sep 2008
Location: DFW America
Posts: 20
Default Proper Radios

Actually, you don't need 'proper' radios for the flight. The AIM allows the use of RNAV systems instead of VOR, DME, ADF, and combinations thereof. If you are using RNAV because the ground stations or your airborne receivers are inop it's called "substitute means of navigation". If all the ground stations and your airborne receivers a working, it's called "alternate means of navigation". You are not required to monitor the ground stations.

Please note that if you are navigating with a localizer facility you must use the LOC. RNAV is not an acceptable substitute.

We sold our last iron gyro airplane in 1992 and I doubt that I've flown a VOR radial more than a couple of times since then.

If I were building a new airplane intended for real world IFR I would install only GPS. Our new bizjets have VOR receivers, but we haven't used them in years. ADF? Never again!

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Old 12-20-2009, 07:36 PM
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Mike D Mike D is offline
Join Date: Jul 2008
Location: Houston, TX
Posts: 453
Default Good info

Thanks everyone!

What I really want out of an EFIS/engine monitor is;
-Do I know where I am?
-Do I know where I am going?
-Do I know if I can get there?
-Do I know if my engine is going to make it there?

I think all the systems will do that. Everything else is a plus to help lighten my workload.

I have a KX-125 nav/comm now. An sl30 would be great, as most of the systems seem to have a way to integrate with them. A GNS530 would be great but $11K buys a whole lot of avgas.

I am not really looking for ďWhat is the best EFIS out there?Ē That is a personal choice based upon mission and ability to accept risk.

One of the questions I was hoping for clarification on is, What makes one system good for IFR/IMC and one not so good? And What are the critical differences that would make one system better for a particular mission (like IMC or acro)? Are any of the EFISís legal for IMC?

I have flown on a cloudless night that I would consider IFR, thankfully with an instructor. But because my family lives in the San Francisco area, which is famous for their marine layer. I would like to drop through that layer. Other than that I donít PLAN on doing IMC. But I am sure no pilot plans on crashing, but sometimes it happens. I am trying to keep that from happing to me.

Battery backups are great but my personal opinion is that sometimes it can be overdone. 12 hours of battery life with an additional 3 hours on the EFIF is overdone. (I have seen it) If something is going wrong, I land. But I need to know when something is going wrong.

This leads to, When is enough, enough? When does the ďfeatureĒ go in the column of gadget? Is synthetic a gadget?

I know I am trying to pigeon hole the EFISís. But it helps me feel good about my choice made on my gut feeling.
Michael Delpier
RV6A -O-320, fixed pitch, GRT Sport, 496
RV-10 - working on finish kit
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Old 12-20-2009, 07:47 PM
ken28117 ken28117 is offline
Join Date: Oct 2009
Location: Charlotte, NC
Posts: 25
Default is easy to say if something goes wrong....I will just land. That is the point....sometimes in hard IFR you have to go missed, having the extra "batteries" or what ever back up system and make a big...BIG difference in getting to another airport or re-shooting the approach.

What is the old saying.....if something can go will usually do it when your in the clouds>
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