March 27, 2011

Garmin GTN - An Initial Look

Garmin has just released their new avionics magic - the GTN series using touch panels and LCD screens. Garmin has lots of experience with touch panels from building and selling their auto navigational units. But, there is a lot of hype surrounding this release. Hype is free advertising but lets take a critical first look at the GTN series - without the hype from a sponsored site.

A Garmin GTN overview video on YouTube.

The new GTN series have a touch screen user interface and accept airways. Hurray! These were the two biggest complaints about the old 430/530 series. Maybe having altitude in published approach segments would be third gotta have for some like myself but we didn't get that this time around. You will still need to consult an approach chart and load/fly the approach as in the 430 units. Terrain and sink rate warnings should keep you out of the weeds. Magic? the GNS 480 had airways since back in 2003 (and remote transponder control). MX 20 had soft keys but no touch screen. The GTN is not so new. Not really magic either. Lets dig in.

Touch screens and Turbulence

No more fixed function buttons. The best way to go for user interfaces is with soft feature functions - be it a dedicated buttons on the side or on a touch pad. The MX 20 had soft buttons as well as the GX-50 series released back in 1998. (It looks like the GTN was designed by the guys in Salem - the original Apollo team). Garmin has provided finger rests to stabilize your hand hovering over the screen. This is the only real option they could use to work the turbulence issues. PIREPS indicate it works well in turbulence. Don't know how this works if you are left handed or the stack is far to the right. The navigator finger guides are setup for right hand use with the unit installed on the right.

Note also that gloves used while operating the GTN need to be 'successfully qualified' by a procedure in the Pilot's Guide. Sounds like FAA speak to me but the GTN uses a capacitive touch sensor - not the 4 wire (i.e. dirt cheap) touch panels used in automotive units.

Screen Real Estate

Buttons are now in the screen display area. In some shared modes, nearly 50% of the screen real estate on the GTN 700 series and 30% on the smaller 600's is used by touch buttons and digit display so the usable map screen is not as big as you think. The first time I saw an actual GNS 530 up close - I just was surprised at just how small the display actually is. The GTN 700 won't be so different when you subtract out the overhead display items like frequency etc.

Easier menu navigation is always provided using as shallow as possible menu tree and by never hiding anything needed to make menu choices. Ideally a depth of 1 is perfect - but impossible with modern navigators complexity. You should realize that old steam panels have essentially a navigation menu depth of 1 which is why transition and operation is so easy on old aircraft. Everybody can work a comm channel. Screen menu's are a necessity when the control elements are too numerous to fit in a shared space. The GPS navigators are still deeply complex devices - and they are all different. The FAA has allowed manufacturers to do what they want regarding operator (pilot) interface design.

Garmin GTN Demo ...another of many GTN videos on YouTube.

VHF Communication is an Option

The bottom line GTN 625 has no VHF comm (or NAV functions) - just the basic replacement navigator for the GNS 400 by size and function.

The VOR/ILS receiver is an Option

The VOR / ILS is an option. Yes, the ILS is going away - costly for the government to maintain but cheap for pilots. Thats why it's going to reverse itself in the future. If you don't want the ILS receiver you are forced to use LPV approaches and keep the database up to date. Can you say: 'single source Jeppesen updates'? Lets hope the new 20,000 4G transmitter site roll-out doesn't interfere with GPS reception too much. The ILS will be here for a long time still.

The VHF Transmitter

The 16 watt RF com transmitter is actually a configurable option via some sort of encrypted key - 'dodgey' at best. In principal I hate this as a user because I know absolutely I am being manipulated by Garmin. The only good news about this wallet grabbing gimmick is that running the transmitter at only 10 watts with hardware designed for 16 watts - results in the transmitter having a longer life.

Rubber Band Editing

Flight plans only require you enter the entry / exit point and the airway. This could be one of the best features coming from the GTN series touch screen. Its possible to edit a flight plan segment on the screen - directly. Way to go Garmin!

Segment Altitude on the Approach?

Any tablet can display a NOS plate for the USA for a few hundred bucks - they display them sourced as PDF files. Garmin optionally displays the approach chart as an overlay too. The own ship symbol is geo-referenced but thats it. You can't see all of the the approach plate and the profile on the screen without zooming in. The source plate is just an image of the approach plate - be it Jeppesen or NOS. The waypoint database would have to be coded to provide the segment altitudes for all approaches. This does not seem to be done in the GTN 700 units. I want to have not only the LPV glideslope guidance - but transition altitudes from the en-route facility. It is clearly possible to have a navigator provide min safe charted altitudes to the final decent point. We should be able to fly the approach using the NAV display functions only. Not done. Nothing better actually than the old MX 20 and paper approach plates.

Remote Mounts

Because the larger GTN 700 version screen is so big, there is the possibility - or outright need for some aircraft - to remote mount the audio panel and transponder. I am not so thrilled to have to leave one screen to enter a transponder code or to adjust the audio panel or worse, change frequencies. More head down time. The screen real estate estate needed for displays consumes some of what is saved by the remount mounts but remotes do give a net gain of stack height. If you do remote mount audio and ATC transponder, you will have to push a button or two to change things. The ATC transponder box is rarely changed once set but COM frequencies are always being worked in the IFR world. At least a list of local frequencies is available. Be nice too if the display said "118.40 ALB Tower" not just COM. We know its COM by the freq range. There is some utility in having dedicated access to those controls - some redundancy if the big box dies.

Older Backup Units

I do not see aircraft installations with two different series navigators being installed - like a GTN 750 with an older GNS 430. It would be too much to manage two different units at the same time for most pilots. I would think a basic NAV/COM (or hand-held) type of setup would work best as backup.

Cross Fill

GTN units can of course cross fill to each other. The documentation does not say whether the unit will cross fill flight plans to older 430/530 or portable units. Likely not. Many owners might consider keeping older GPS equipment as backup. I personally would find this double install way above and beyond being practical - so this may not be a real issue.

Entry Speed

GTN units seem to have a slowish UI. You can press numbers faster than what the unit will accept.


The GTN does have a battery to maintain the real time clock in the GPS receiver engine. Used for a quicker start in getting an initial navigation solution (and retain the last satellite almanac data). Contact the dealer for service. A battery must be replaceable by any local shop.

Inputs (ADS-B, Terrain, Radar, Traffic, Stormscope...)

Stormscope, Datalink Weather and Traffic can be displayed with suitable external hardware. There are manuals for all the details available on Garmin's site.

Just a note that the terrain function uses a computed (GPS WAAS) altitude and has a 1000 foot color step. There is no barometric altitude input used (transponder serial or a static port). There is no requirement to set the local altimeter setting in the GTN box.

Design Life

Its been 13 years since the GNS 450/530 came out. Thats a pretty good run for a product. Remember, there are actually several hardware versions of the 430's. Some with 12V only power supplies, some with 12/24V switch mode supplies and some WAAS units. The early 430's are no longer fully supported and with the GTN series replacing them they will have another year or two of production life, maximum, before Garmin drops them. Garmin would support the 430W/530W series only while parts are available for a short number of years after that.

Do you own your configuration?

I have it that the configuration menu can be accessed only with a secure card which only a Garmin dealer will have. Garmin also limits permissions to use their AML (approved aircraft model list) STC's to authorized dealers only, This actually prevents a non Garmin dealer from filing a 337 with the AML STC as approved data (and the FAA now enforces this). Installation manuals are restricted access too. And we thought Narco was bad? There are calibration items stored in the unit as well - corrupt this table and it's bricked - repairable only by the factory on the automated test equipment.

Marketing and Purchasing Costs

Priced well up there for the rich airplane guys. Not for the Cessna 150 crowd. Maybe Bonanza's and Cirrus drivers that don't have glass. Some will load up a $40k Warrior with a small GTN 625/650. Repair will be around $1000 per event after the 2 year warranty. It would be nice to see 3 years or a 2 level repair cost schedule. The GTN 650's can replace the older GNS 430 with a tray and some wiring changes - they consume the same stack height.

So, who is going to go with the GTN line ? If you already have glass, no unless you have 430's to unload from your Cirrus. If you have a 430/530 and a MX 20/200 - maybe it's time to upgrade. If you have a Bonanza with steam gauges and older NAV/COM's - likely. Bleeding edge / gadget freaks will certainly pony up right from the start. But remember, you are looking at a 12 year life so the depreciation will be quick. Lets say an owner installs the following equipment...

GTN 750 $17,000
GTX 33 Xpdr 3,000
GMA 35 Audio $4,000
24,000 + install = $28,000 estimated purchase cost
+$800/year subscriptions*12 years = 9,600 (many less)
+2000 for 2 major service events
39,600/12 years = 3300 per year (- trade ins)

Now, assuming 150 flight hours per year makes this avionics cost around $22 per hour. More or less.

Garmin's Margins

Garmin sold about 120,000 GNS 430/530's to date. Last year Garmin reported sales in the aviation segment of $263 million (about 10% of all business). Lets say $7,500 average revenue after dealer discounts split between the GNS 430/530 units. This is close to a billion dollars of aviation sales - maybe half of their total aviation product sales revenue over the 13 years. Gross margins for the aviation segment (highest of all 4 segments) is reported as 70% so we are looking at around a build cost of $2250 which yields a cool $630 million lifetime profit or $52 million profit per average year just for the older GNS 430/530 series. With these margins there is definitely some room for competition even with expenses to come out.

Helping America's Economy

So you pony up $17 grand for a new GTN and feel good - the money goes to an American Company, right? Well, not so much. The install costs of course stays here. Garmin is under a Swiss Incorporation and so it pays 12% Swiss instead of 35% US corporate tax. But, since it has the Swiss 'pied-a-terre', those profits must stay out of the US to keep this tax advantage. So the gross profits never come back to the USA. Again, lets figure after dealer discounts etc., Garmin receives 12,000 per GTN. The gross margins at 70% make the gross profit about $8400. There are so many units sold that the R+D (which does stay in the US) is only a small part of this - say a generous $1400 - leaving $7000 - after Swiss tax about $6100. So for every unit purchased, $7000 immediately leaves the country and $800 goes to Switzerland and $1400 goes for R+D. Don't forget a lot of chips and displays are likely manufactured in Asia too - a big part part of the $3600 production cost. Bottom line - half of the money leaves the US permanently.

Bottom line: A Good but Expensive Unit

It all comes down to the mighty Dollar, Mark or Yen. The GTN 600/700 are nice units if you ignore the total initial outlay, outsourcing loss and ongoing costs. It will get you where you need to go. Overall, not so much magic - but natural hardware evolution. Expensive: yes. Nice: yes. Still complex with a 400+ page manual: yes. I was hoping less expensive.

As I watch my $1000 54 inch plasma display run by a $700 PC running open and free Linux/Ubuntu, I have to ask the obvious question - where's the bloody competition? Come on Aspen and Bendix King!

Update: Aug 15, 2011: Avidyne has announced a plug and play touch screen replacement for the Garmin 530 - the IFD540. This will take a lot of the GTN business from Garmin. If Avidyne can deliver close to on time - it looks like a winner. (I was beginning to think there was no hope for a better deal. This is the first thing to come along in years that I am actually interested in).