GNS-430 or GNS-480  How do you decide?

After a lengthy online feud, I decided to gather and compile some things on these systems so you could have a reference without waging a war.  This is a quick write-up of things that I could find.  There will be far deeper info available if we can ever find a true "expert" to list them.  One thing to keep in mind is that software versions on both sides may have been updated.  Much of the discussion I found was either pre-2.0 on the CNX-80, or version 2.0.  Currently the GNS-480 is running version 2.1.   I do not know the revisions of the 430 so it is possible they have updates as well.  Also note that this info was compiled from internet sources, and that means it isn't always reliable. In addition, I have left out any some comments such as "Easier to Learn", because both system will require the user to become familiar with a very involved system, and while one may be easier to learn for some simple functions, it may be completely opposite for real complex functions.  It's been said that either system will be easy to learn once you buy it, because you will learn what it is that you fly.  It is far more difficult if you are renting various aircraft, but that is not the common concept required for those building their own plane.

The Pro-Con List:

GNS-430 GNS-480
Pro: Has possibilities of Terrain features in upcoming versions (430W) Con: No Terrain
Con: Does not include Airways in the system Pro: Allows easy entry of multi-segmented Airways with minimal steps
Con: TSO-C129 Only Pro: TSO-C146 - LPV Gamma-3 Approach Capability (**currently under SB)  (means: Has WAAS)
12 GPS related Buttons 19 GPS related Buttons
Pro: Can tune radio and change GPS simultaneously Pro: Has HSI Screen
Con: Smaller Screen - only 4 data fileds on map page Pro: Larger Screen
Pro: More consistency in Menu functions Con: Can only change GPS function or COM functions non-simultaneously
Con: No CO Guardian integration Con: Less consistency in Menu Functions - Methods change depending on mode.
Pro: Functions similar to G1000 if you're considering upgrading to G900 Pro: 4 customizable Map Pages
Con: Requires hitting SUSP to navigate on the Missed Approach. Pro: CO Guardian CO monitor integration reading CO PPM, Cabin Temp/Pressure
Possible Con: May need to verify if vertical coupling is possible with TruTrak Digiflight VSGV AP's.  Unsure if AP's software is designed to accept vertical commands from GNS-430s. Pro: Doesn't require hitting SUSP to go missed.  Landing gets it out of Missed mode, and going flying Missed automatically transitions it into Missed mode.
Holding CLR for 3 seconds gets you back to fresh screen if you're messed up. Pro: Will command TruTrak Digiflight VSGV AP's (or higher) for both Lateral and Vertical coupling during approach:
Pro: More Overlays: (Weather, Traffic, Stormscope...)  (note: weather is not good high res, so you will want this on a better MFD anyway) Hitting MAP button gets out of current mode if you're messed up and gets you directly to a fresh screen.
Con: 1 Map Page Con: Less Overlays: (Traffic is available.  No Weather, Stormscope...)  (note: the traffic works well, but you will want this on a MFD anyway)
Big Knob, Little Knob, Cursor On, Cursor Off lets you master this unit. Big Knob, Little Knob, Cursor On, Cursor Off, Press the button, what mode, Execute the change lets you master this unit.
Pro: In an emergency, pilots have less buttons to hit to get the unit to change its navigation than the 480. And that navigation change does not dump the original flight plan. Con: When you change Navigation, you must cancel or amend the current flight plan.  May have to "Go Direct" and then start entering your new plan.






Additional Commentaries:

The 430 is pretty ancient by now (1998). The processor is slow and it doesn't do most of the good things that the 480 does (victor airways, WAAS precision GPS approaches). The 430 has the advantage that it prepares you to fly other airplanes because so many of them have 430s and it is also reasonably good preparation for the G1000, which seems to have been programmed with the same philosophy. The 480 is designed to be paired with the MX20 and therefore I think it doesn't have some of the useful VFR stuff that the 430 will eventually have when it is upgraded, e.g., terrain, and a good database of roads and bodies of water. -- Philip Greenspun, February 15, 2006
Plus there are other GPS/MFD options out there too. I have a 430 driving an Avidyne EX500. With the big versatile MFD showing weather/traffic/etc., there is rarely a need for the 430 to be in map mode, so its compact size is an asset.
- FChE
A 530/480 combination loses the crossfill ability of a 530/430, 530/530, or 480/480 combo. You'll have to learn both units instead of one unit. Other than that, you'll get the best and worst of Garmin in one panel.

MX20 versus the EX5000 is no comparison. The Avidyne units talks to more interfaces, is far more intuitive, and has a larger display. If you meant the EX500, it too knocks the MX20 out of the air. My ideal panel is dual 430s with an EX500(0), followed by the G1000.

As for the 430 versus the 480......
I never could find the copy of my old comparison, so here is a new one. I am a  Master CFI and an expert (per a bunch of folks including Garmin) on the 530, 430, 480, G1000, and a bunch of other units. My specialty is training these gee-whiz boxes. I can take someone who has never used a computer before and have them successfully completing a GPS approach by the third lesson.

Ok, 430 versus the 480:

480:
Has 13 fixed buttons and  9 changeable buttons. Depending on the mode of the unit, the functions of those 9 buttons change. Of those buttons, 3 are dedicated to COMM/NAV/Transponder, leaving 10 fixed and 9 changeable to the GPS.

Slightly larger screen than the 430. Has a discontinuity 'feature' making the unit think the pilot bought this GPS to do anything BUT go GPS Direct.
Requires expanding the flight plan, making the change, then executing any change made.
Has Airways. Big whoop. I almost never fly them, and when I do, I put in two waypoints that define the route, either intersections or VORs, and I have the airway.
Has WAAS. So it is down to 7 feet and not 14.
Allows for precision GPS Approaches. Cool. The 430 will have those by the end of the year. (Note: This was written in 2005, and it is still not here approaching 2007.)
Neither allow the autopilot to follow the glideslope until the autopilot manufacturers catch up.
(Note:  This is no longer true, in the the 480 will allow Lateral and Vertical guidance approaches with TruTrak Digiflight AP's)
Doesn't require hitting SUSP while going missed approach. On the other hand it always assumes you are going missed approach.
Has a HSI screen. Good for backup, but I use the external CDIs more often.
Default go-directly-to-start button is MAP.
Multiple ways to do something, but only certain ways are available depending on what page or mode the unit is in.
Frequency changes require stopping whatever GPS input was being made to make the frequency change.
Four customizable map pages that require a lot of tweaking to be usable.
Overlays include traffic. If you want more, buy an MX20.
Big Knob, Little Knob, Cursor On, Cursor Off, Press the button, what mode, Execute the change lets you master this unit.

430:
Has 17 fixed buttons. They work the same way every time. Of those 17, 5 are dedicated to the COMM/VOR radio, leaving 12 for the GPS.
Slightly smaller screen than the 480.
Unit assumes you will go GPS direct when no other course method is available.
If you change something in the active flight plan, you make the change.  Done.
Requires hitting SUSP while navigating on the missed approach, until the WAAS upgrade.
Default go-directly-to-start button is CLR, hold for 3 seconds.
In an emergency, pilots have less buttons to hit to get the unit to change its navigation than the 480. And that navigation change does not dump the original flight plan.
Faster to learn and use. Pilots as a whole seem to catch on faster with the 430, and use more of its features as compared to those I've trained on their CNX80/480s.
While there are multiple ways to do something, those ways are consistent no matter what mode the unit is in.
You can actively work the GPS and the COMM at the same time. The co-pilot can put in the new course while the pilot puts in the new frequency. Or you can be in the middle of a change to the GPS course, stop, dial in the new frequency, and continue exactly where you left off in the GPS.
One Map Page, highly customizable.
Overlays include traffic, weather, Stormscope, and so on.
Big Knob, Little Knob, Cursor On, Cursor Off lets you master this unit.

Overall, software version 2 was a big help to the CNX80/480. (Note: Version 2.1 is now available) It can do a couple of things the 430 currently can not do, but not for long. It requires more button pressing and has a steeper learning curve than the 430. Software version 2 was slapping a bandage on a human factors nightmare (no offense to my friends in Salem). I'm hoping Version 3 will make even more improvements.

Faced with deciding between the two, I recommend the 430 and save the 2K for the WAAS upgrade later this year.

But don't take my word for it. Download both simulators, get the manuals, and start playing with the boxes. You can also get a copy of my Inflight Quickref Guide (www.slantgolf.com), the 'Cliff's Notes' to these units, and use the simulators or head into your local avionics shop with the units on display. While the manufacturers manuals are okay, mine just simply give you the button presses and knob twists to do something. Either way, they allow you to find out for yourself which unit is easier for YOU to use.

This is most important. Which unit is easier for you, the one that has to use these? Your flight instructor probably knows one, maybe two, and as their own preference they usually choose the one they learned first.   Do you need airways which require plugging in the starting point and the exit point? Or can you plug in the starting point, the course changes, and the exit point once, save the flight plan, and not have to plug in the course changes again?

Do you happen to live at an airport with an LPV approach that is actually to lower mins than the other approaches to the airport? Will you actually fly down that low or are your personal mins much higher?  (BTW, we have an LPV approach available to us, about an hour away. Mins are twice as high as the ILS and slightly higher than the GPS LNAV approach.)

Do you want to deal with the "Microsoft"-like 'are you sure you really want to go GPS direct with your GPS unit?' 'Ok, I'll let you go Direct, but if you don't save your changes, I won't do it and won't tell you why.'

It's your panel. Choose wisely.

Fly SAFE!
Jedi Nein

AND The Flip Side Response


I'm really happy I didn't consult you before buying my CNX80 and MX20.  I'd never denigrate the 430/530 units, but I really prefer my CNX80.  TSO-C146 vs. TSO-C129 was a no-brainer choice for me, and I was unwilling to wait for the (probably expensive) 430/530 upgrades. And I certainly did compare the simulators before purchase, too.

For MFDs, however, I think the MX20 is better than the EX500. If I'd been happy enough with the EX500, I wouldn't have had to replace my radar to be able to control it through my MFD. I've never been up close to an EX5000, though, so I don't know about it. Its specifications read pretty well.

Your advice to choose what one likes best is certainly apt. It's much more apt than adopting anyone else's prejudices. My own prejudices are bad enough.  :-[

<continuation>
No, that was a customized *snip*.  I didn't want to pick nits about your comparison, but since you asked...

You seemed to involve the 480's discontinuity 'feature' in going direct.  The discontinuity is part of an incomplete flight plan,  and is not involved with navigating "direct-to" a selected location.

You said you can put in two points to "define the route",  and thus "have the airway". However, few airways go very far along a single great-circle path. With the 480, you don't need to enter intervening airway inflection points. I agree with you about almost never flying airways, but our friends in the northeast U.S. seem to be constrained to airways frequently.

You said neither the 480 nor the 430 allow the autopilot to follow the glideslope until the autopilot manufacturers catch up. I don't know what that "catch up" would be, because my own 30-year-old, three-axis autopilot flies the VNAV approaches quite well, including arming and capturing the glideslope, exactly as it does ILS.

You said the 480 always assumes you are going missed approach.  The 480 does not assume you are flying a missed approach if you land and decelerate on the rollout. When I do a missed approach, the 480 gives me guidance automatically, after I climb the requisite amount to begin the missed approach.

I actually didn't understand what you meant by "Default go-directly-to-start button is MAP", so I'm unsure if that was a complete statement or not.
I don't mean any of the above to detract from the 430/480 comparison you posted, and it's always good to see opinions such as yours in the open.
I only have experience with the 480 and, I must say, it is simple to use.

From what I have been told, two of its advantages over the 430/530 are:
1. Ease of flight plan entry -- you can usually enter it just as ATC reads it to you as the airways and all relevant intersections are in there. If  you have an airway that has multiple turns at various VOR's or intersections, you don't have to enter all those fixes, as I'm told you do with the 430/530.

2. The 480 is certified under TSO-146. This gives you some advantages in selecting alternates; and also gives you vertical guidance on most GPS approaches (even the straight LNAV approaches). Although I initially pooh-pooh'd that idea, having accomplished many non-precision approaches in my flying lifetime, the first time I executed a GPS LNAV approach into my home base with the advisory vertical guidance, I became a believer in it's ability to make the approach easier for me.

Ron (EPM) (N5843Q, Mooney M20E) (CP, ASEL, ASES, IA)
My club has the GNS-480 (nee CNX-80) in 6 of our planes, and for the most part, we love them. I only have a little bit of 430 time, so I really can't do a fair comparison, but my impression is:

1) The larger screen on the 480 compared to the 430 is a real advantage.  Of course, the 530 trumps the 480 in that respect, and the MX-20 trumps them all!

2) The operating logic on the 430 is simpler than the 480, but once you've invested the effort to learn the 480, it's a more powerful box. If I was equipping a rental fleet, I suspect I would go with the 430 because it's easier to learn. For a personal plane, that's less of an issue.

3) The MX-20 has one near-fatal flaw: the processor in it is WAY too slow.  To call screen updates lethargic would be kind. If Garmin were to come out with processor upgrade, it would be a killer box. As it is now, I don't think I would recommend anybody buying one today.

Perhaps the most annoying aspect of the 430 for me is that one can display only four data fields on the map page. I want five: next waypoint, distance to next waypoint, groundspeed, desired track, track.

I just took delivery on my GNS480 upgrade, and in the initial test flight, did not see what you are  experiencing. We flew the GPS23 approach into P08 (Coolidge, AZ), and the GPS07R into KDVT  (Phoenix, Deer Valley), and VNAV guidance was provided on the external HSI in both cases. Interestingly,  these are traditional GPS approaches, not the newer ones with specific LPV or LNAV/VNAV minimums, and VNAV was provided in both cases. In the Coolidge case, we took it all the way down, and it split the runway laterally and the G/S pointer took the altitude right to the threshold. All this out in the middle of the desert with no ground navaids. Very cool.

So, I'm confused by what's causing your restrictions. Could it be something specific to your F/D-A/P  setup? I don't have either one, so maybe the logic is restricted only if there's an autopilot. Or perhaps WAAS updating was unavailable when you tried it. Is it restricted even when WAAS is known to be working?

Mike