Garmin GNS 530/430 GPS Nav/Com

reviewed by Philip Greenspun in March 2002; updated July 2008

Site Home : Flying : One Article

The Garmin GNS 530/430 combination is a common dual-GPS avionics suite for an IFR-certified airplane, costing around $20,000 plus a $500 per year subscription fee for Jeppesen database updates. A single 430 or 530 functions as a communications radio (COM), a VOR/ILS/GS receiver (NAV), and a moving-map GPS.

This review is based on 700 hours of usage in a 2002 Diamond DA40 and 300 hours of usage in a Cirrus SR20.

Let's start this review by considering the things that a pilot needs to know while in flight. We'll then go through these items and see how the information can be obtained from the Garmin GNS 530/430 combination. Here's a partial list:

Terrain Information

The Garmin provides no information on terrain height. If you give it a flight plan it can't tell you how high you need to go for terrain clearance. If you're going cross-country at night, it can't warn you that you're about to come upon a high dark mountainside. If you're worried about all those towers that are marked on sectional charts, you'll be worrying without any assistance from Garmin. So you can pay your $15,000 and $500 per year but you'll be doing exactly what a pilot in a rented ragged out 1975 Cessna 152 is doing: buying new paper sectional charts every few months, filing them carefully, referring to them in-flight while holding a flashlight in your mouth. The Garmin is useful in determining terrain clearance only in that it can give you a current position latitude/longitude for plotting on the paper chart.

[The Garmin does have one extra feature that might be useful if you had to take over the controls and flight planning over unfamiliar terrain at night from a pilot who had collapsed: MSA. You can configure the unit to show "minimum safe altitude" pulled from the Jeppesen database. In flying over Kansas this turned out to be very close to what the paper IFR chart said. In flying over New Mexico the MSA displayed by the Garmin was 2000' higher than the paper chart's recommendation and more than 4000' higher than the plateau over which the airplane was traveling. On balance it is about as useful as telling someone "if you fly above 20,000' MSL you won't hit anything between San Francisco and New York."]


Supposing that you're an IFR pilot and ATC gives you a new clearance in mid-air, part of which involves traveling on Victor airways. What help does the Garmin 530/430 combo provide in finding and following this airway? Maybe if your flashlights fail you can use the glow coming off the screens to read your paper enroute chart. That's right. Despite your paying the $500 per year subscription fee to Jeppesen, the Garmin does not display airways nor can airways be entered as part of a flight plan. You must make sure to buy new paper IFR enroute charts every 56 days just like the classic Cessna 152 pilot.

Because there is no way of entering an airway into a flight plan, the Garmins cannot display information on minimum enroute altitudes (MEAs) or minimum obstacle clearance altitudes (MOCAs). Suppose that you're picking up a bit of ice in the clouds. You recall from an earlier weather briefing that the freezing level was 8000 feet. You'd like to know how low you can go, legally and safely, on this airway before calling ATC. You'll need to refer to the paper charts.

Instrument Approach Guidance

The Garmin 430 and 530 can display a pretty birds-eye picture of an instrument approach. It looks sort of like an approach plate. However, unlike an approach plate the Garmins will not give you any vertical guidance, i.e., they cannot display any information about how low you can descend during a particular current section of the approach. A friend and I watched the Garmin training video in astonishment as the lecturer demonstrated flying several approaches. He did all the approaches at a constant altitude and never descended or climbed when going missed. Just like the pilot of that ancient Cessna, you'll be buying paper approach plates every 56 days and balancing them on your knees if you want your approach to include a descent toward the vicinity of the runway.

Nearby Airports

Suppose that you're flying along VFR and the moving maps of the 530/430 show that your track will take you right over an airport. You'd like to tune up the airport's AWOS to get a current altimeter and then announce your overflight on the airport's CTAF. Here's how you do this on the Garmin:
  1. turn the little knob so that you're on Nav Page 2, the "map page"
  2. press the little knob in to turn on "cursor mode"; a little arrow shows up on screen
  3. twirl one knob until the cursor arrow is horizontally aligned with the center of the airport symbol on the map
  4. twirl the other knob until the cursor arrow is vertically aligned with the center of the airport symbol on the map
  5. perform a fine adjustment of both knobs so that the arrow is within a couple of pixels of the center of the airport symbol; the airport symbol will begin to flash
  6. locate and press the Enter button; a screen showing the name of the airport appears as well as some other information but not the frequencies that you need
  7. be careful not to press Enter again because the cursor is currently over the "Done?" symbol and if you press Enter all of your work will be lost
  8. press the little knob to turn off cursor mode
  9. rotate the little knob until the airport page with frequencies appears
  10. press the little knob to turn on cursor mode
  11. rotate the outer knob until the cursor is over the AWOS frequency
  12. press Enter to place that frequency in the COM standby position
  13. press the frequency switch button to swap active and standby COM frequencies
  14. ..
Could you learn to do this procedure? Sure. Can you learn to do this procedure without taking your attention away from flying the airplane and watching for traffic? Unlikely. Garmin is relying on the pilot staring continuously at the 530/430 screens, watching a cursor move, while manipulating the knobs. Only by watching the screen can you tell whether or not you've got the cursor adequately positioned over the airport symbol. Only by watching the screen can you tell whether or not cursor mode is enabled.

[Note that you could accomplish this via the Garmin's text Nearest Airport page but it would be nearly as many keystrokes, nearly as much reliance on positioning the cursor, and you have to figure out for yourself how the airports listed on the Nearest page relate to the little symbols that you've seen on the moving map.]


Suppose that you're flying around in Montana for a couple of hours. As you get near the Missoula airport a MSG warning light on your panel begins to flash. A flashing "MSG" appears on the GNS 530. There is a small text area at the lower right of the screen but it is blank. Only by pressing the MSG button on the GNS 530 can you learn what the Garmin has to say. Upon pressing the MSG button the entire moving map display is obscured by a mostly blank screen upon which is written "Airspace 10 minutes ahead". Your display remains obscured until you press the MSG button again.

This warning motivates you to tune Missoula Tower on the GNS 530 COM side. You're talking with ATC and the MSG lights begin flashing again. You press the MSG button and learn "Airspace 2 minutes ahead". You press the MSG button a second time to restore the navigation display. The tower has cleared you to land and you're busy getting the airplane set up for a straight-in approach. While on final, the annunciator panel and the Garmin are flashing again. Two more presses of the MSG button and you learn that you're "Inside Airspace".

Was this distraction necessary? Consider that the communications radio and the airspace warning system are inside the same physical box. The GNS 530 has seen you select the tower frequency from a menu of frequencies for the Missoula airport. The GNS 530 has seen you key the microphone and transmit on that frequency. Can it not infer that you've figured out that this is controlled airspace and suppress additional warnings?

Taking off from a Class D airport the experience is similar. The Garmin watches you select ATIS, Ground, and Tower frequencies. The Garmin watches you transmit and receive on Ground and Tower. You're climbing out, carefully monitoring your gauges because you know that this is the riskiest phase of flight for engine failure and other mechanical problems. The annuniciator panel begins flashing. You panic a bit and then realize it is only the MSG light. You press the MSG button on the GNS 530 and learn that you're "Inside Airspace."

Flying through Class C or Class B airspace typically sets off 10 to 15 warnings from the GNS 530. You're already inside the Charlie and yet the Garmin is screaming "Airspace near and ahead". One possible explanation for this phenomenon is that Garmin's programmers have modelled each section of a Charlie or Bravo as a separate chunk of airspace. Thus as far as the Garmin is concerned when you go from the outer ring of a Charlie to the inner ring it is just the same as if you went from a military operating area into a Class D.

There is no way to tone down the airspace warnings from the Garmin. With some cursor gymnastics, you can turn off warnings for different classes of airspace. If you're going to be flying IFR, for example, you can turn them all off with about 25 keystrokes. But if you want any warning at all about a Class C you've got to accept 15 warnings about each Class C through which you transition. If Garmin can't make its software smart enough to link up the pieces of a Class C, it would be nice to have a menu option to "mute airspace warnings for 15 minutes" from the message screen. But pressing the Menu button while a warning is being displayed reveals no options at all. I mentioned this possible enhancement to a Garmin field rep and he stared back blankly.

VOR Navigation

The Garmin GNS 530 has the very useful ability to show, for any VOR being received, the radial and distance from that VOR. The distance is pure horizontal range calculated using the GPS and does not depend on traditional DME equipment in either the airplane or at the VOR. The display is continuously available in a little box at the bottom left of the screen, which makes it easy to maintain general orientation, report one's position to ATC, or fly a DME arc. One of the nicest tricks of this box is that the GNS 530 listens to the Morse code being broadcast on a VOR or ILS. If it is able, the GNS 530 displays the decoded identifier above the radial and distance. In other words, the GNS 530 can "tune and identify" a radio navigation aid.

The GNS 430 lacks all of these features.

Summary of Fundamental Shortcomings

The Garmin 430/530 combination suffers from at least the following fundamental shortcomings: Until these shortcomings are addressed there is no legal or practical way to fly without the full complement of paper products that pilots in the most primitive airplanes must carry.

Operating Logic

Given the things that the Garmin GNS 530/430 combo actually does, how well does it do them? "With a lot of head down time" is the answer. Here's an excerpt from, an NTSB investigation of an accident involving a Garmin GNS 430-equipped Cirrus SR20:
"The pilot was in the process of selecting the approach in the airplane's global positioning satellite (GPS) receiver [GNS 430], when he noticed that the turn coordinator was "pegged to the left, with no flag," and that the airplane was losing altitude rapidly. The pilot disengaged the autopilot and attempted to stabilize the airplane."
A regional jet pilot spent 100 hours flying with the Garmin 430/530, read every page of the user's manual, watched the training video, and concluded that "The capabilities of the units can be impressive but they are way too hard to use; in our $20 million jet you're set if you know how to read English and push buttons."

One reason the Garmins are so hard to use is that they don't have soft keys. Suppose, for example, that a screen in your airplane is displaying a list of frequencies for an airport. You can see the frequency that you want right in front of you. If voice recognition systems were more reliable it might be best simply to speak to the airplane: "tune ATIS". If you had a touch screen and clean fingers it would be easy to touch the ATIS frequency. But what most of the good avionics interfaces do is provide a line of buttons next to the lines on the display. If you push the button next to the ATIS frequency, you've tuned ATIS. This button doesn't have a label on it because on a different screen it would have a different function. That's what makes it a "soft" key. The true multifunction displays such as the Avidyne and the Garmin/Apollo MX20 all rely on soft keys, as do some car stereos (the LCD labels above the buttons change depending on whether you're listening to radio, cassette, or CD).

Much of the hysteria surrounding airspace and other messages from the Garmins could be eliminated if they rolled the message through the text area in the lower right corner of the screen. Most of the messages are very short and there is no reason to ask the pilot to take his or her hands from the flight controls to press the MSG button twice.

Better integration among the Garmin components would help. For example, suppose that you want to listen to a weather report broadcast on a VOR. You tune NAV1 to the correct frequency. You press NAV1 on the Garmin GMA 340 audio panel. You can't hear the weather. You fiddle with the NAV1 volume control. You still can't hear the weather. Then you remember that you have to take your eyes away from the instruments and traffic for a moment to see if a little "ID" symbol is lit in the NAV1 data block. If isn't. So you press the NAV1 volume control knob in to engage "ID mode" on the GNS 530. Given that both the audio panel and the navigation radio were both made by the same company, why wasn't the navigation radio smart enough to switch itself into ID mode as soon as the pilot indicated a desire to hear what was on the nav radio (by pushing the button on the audio panel).

A Cirrus owner comments:

"I am very disappointed with the Garmin 430 pair in my SR20. The Avidyne gives you a more detailed moving map but the combo is nowhere near what the Apollo MX20 does (actual charts). The Garmin/Avidyne combo has no vertical information (i.e MEA's, approach heights, etc.) so you have to have paper charts for everything.

"When you tell other pilots that the Garmins suck they usually say 'Oh, that's because you haven't used them enough; once you learn them you'll love them.' But these are mostly guys who've only flown older airplanes with primitive Nav/Coms. People who have some experience designing user interfaces are appalled."

My personal conclusion is that the Garmins are, by and large, unsafe for single-pilot operation. It may be possible to use some of the unit's sophisticated capabilities if you program everything in advance on the ground but if things change in-flight you must always be prepared to revert to basic moving-map and paper charts.


The squelch level of the NAV radio is not pilot-adjustable. My Diamond Star apparently has a rather poorly grounded and/or isolated electrical system. Electrical noise from the autopilot servos leaks into the NAV radios, which is very annoying when the autopilot is flying through anything other than the smoothest air. The squelch level of the Garmin 530/430 can be adjusted only by an avionics shop and it was adjusted so that the autopilot's noise no longer breaks squelch. Sadly, however, if you're flying in more isolated regions it is impossible to hear ATC unless you press the volume control knob in to disable squelch altogether. So you're forced to fly along with a constant static noise in your headset.

Most older standalone NAV radios have squelch that a pilot can adjust in flight and this would be a welcome improvement for the Garmins, at least in a noisy electrical environment such as the Diamond Star DA40.


If you're flying around at FL 310 and get confused the Garmin has a useful "nearest Center" page that will give you the frequency of the controlling ARTCC. However suppose that you are flying at 3000 AGL in a congested region of the United States and want to request flight following. You probably want Approach, not Center. The Garmin does not provide any practical assistance in figuring out which Approach control is responsible for the airspace in which you're flying.

Nice Things

One nice thing about the Garmin GNS 430/530 combo is the quality of the displays, which are highly readable in all ambient lighting conditions.

A useful feature of the GNS 530 is the ability to establish user-defined warnings. For example, you can have the Garmin give you a "switch fuel tanks" warning every 30 minutes.

When you're out on a long cross-country it can be fun to look at the GNS 530's odometer page, which shows the total number of nautical miles traveled since the 530 was installed (there is also a resettable trip odometer).

Technical Support

Garmin tech support was able to answer my early questions about the unit's capabilities. If you're willing to wait on hold for 15 minutes you can talk to someone who is reasonably well informed.


All of the Garmin manuals are available on the Garmin Web site for free in PDF format. The Eastern Region Safety Team of the FAA publishes some free Garmin 430/530 training videos.


If you're very tight on panel space in an older airplane and want to replace a dead Nav/Com with a Nav/Com/GPS, the Garmin GNS 430 may well be a reasonable option. Don't expect the user interface to be better than the equivalent King product, however. Nor should you expect the overall utility of the panel-mount Garmin to be significantly greater than that of the cheapest moving-map portable GPS. Unless you've got a copilot with the owner's manual spread out on his or her lap, the Garmin is going to give you nothing more than basic horizontal positional awareness.


Operational Tips for Users

This section will be an ever-expanding list of procedures for getting the most out of your Garmins. If you have an idea, please click the "add a comment" at the bottom.

Coming into an airport without an ILS

Even if the weather is perfect, when landing at an unfamiliar airport it makes sense to tune up the instrument landing system (ILS) frequency for the runway that you're planning to use. This may prevent you from landing at the wrong airport (a big Delta Airlines jet did this in 2001 or 2002), landing on the wrong runway, being way too high or low, etc.

What if your destination airport lacks an ILS? Twist the OBS on your HSI to the runway heading, e.g., 290 if you're landing on 29. Push the "OBS" button on the Garmin. The GPS moving map will now display a big extended runway centerline while your HSI will show you graphically how far you are from that centerline.

What is the heading to that distant airport/VOR?

Suppose that you're on an instrument flight plan in eastern Pennsylvania bound for Bedford, in the Boston area. It is a busy day in New York City and the controllers have told you to fly "Direct Lake Henry". You punch this into the Garmin and the resulting heading feels like it is going to take you halfway to Buffalo before you get turned back toward Boston. The worst of the front is behind you and you're in visual meteorological conditions (VMC). Does it make sense to cancel IFR and go direct to Bedford?

You can bring up KBED in the Waypoint pages but none of them will give you the bearing to the waypoint. You won't find KBED in the Nearest pages because it is too far away. The solution is to tell the Garmins that you want to go direct to Bedford but abort the procedure at the last step: press the direct button, dial in KBED using the cursor wheels, but press the clear button instead of enter when prompted for the final activation. The last screen that you see should give you the distance and heading to Bedford, thus enabling you to evaluate whether or not your current clearance is getting you anywhere near your goal.

Avionics Discussion Group

Text and photos (if any) Copyright 2002 Philip Greenspun.

Reader's Comments

Here are a couple of useful tips I got from a very good CFII

Did you know about this bizarre behaviour where the GNS430 will deactivate the approach if you're even just a little off of the FAF? The natural reaction of most people is to "reactivate the approach", which will send you back to the IAF - not a good idea when on autopilot with 500feet/min descent rate dialed in...

-- Christian Goetze, April 10, 2006
Hello Phillip,

For finding the nearest approach or departure controller, it requires a few (many) more key presses knob twisting, but here's a way you can do it: Go to the nearest airport page, and pick the nearest airport. Bring up that airport's frequency page, and find its departure or approach frequency. This is more often than not the proper apch/dep controller for the area, or someone who can hand you off correctly.

-- Joshua Levinson, February 17, 2009

I just came across your review of the Garmin 530/430. I have to say that I think your view of the GNS530 being "nearly impossible to learn" and "unsafe" is a bit off the mark.

I fly the Boeing 747-400 and I find the system logic to be very similar to the Boeing and very user friendly. These units are designed for IFR flying. They do have a few things that are missing like airways and altitudes but they are very good in the IFR environment. If you just have the basic understanding that you can only navigate to a point and not from a point you are halfway there. Remember that these units are over 10 years old now. There was no such thing as an iPad or touch screens 10 years ago. They don't do everything for you but they do what you need very well.

-- Lance M, November 28, 2011

Add a comment | Add a link