On Display

Going the WAAS Way

June 1, 2007

Upgraded Garmins bring a host of new features

Logic might suggest that the primary reason to upgrade your Garmin GNS 430 or 530 would be to take advantage of the hundreds of Wide Area Augmentation System (WAAS) approaches now available. And if we flew instrument approaches on every flight that logic would rule, but, in fact, we fly instrument approaches on the minority of flights. However, we are concerned about weather conditions on nearly every flight, and that's where the primary benefit of the WAAS upgrade comes. The upgrades necessary to support WAAS approaches also provide the processing horsepower to dramatically improve the way 430/530 owners access and utilize datalink weather information through the Garmin GDL 69 and GDL 69A. The GDL 69 is the system that receives, processes, and then displays XM WX Satellite Weather information. If you have the 69A, you also get XM satellite audio entertainment.

With their new computing horsepower, the WAAS-enabled Garmins provide Nexrad radar images at 16 times the resolution of the old version. In addition, Garmin has added the ability to display graphical temporary flight restrictions (TFRs) on the moving map and graphical METARs — shown as colored flags depicting current weather conditions on a dedicated weather page. The old version showed graphical METARs in a less intuitive way. Also new to the Garmins' bag of tricks is the ability to display terminal aerodrome forecasts (TAFs).

Besides the new products, the interface for getting at the weather information is improved. Nexrad still can be overlaid on the primary navigation page, but the WAAS boxes also add a dedicated weather page where you can more easily see Nexrad over a larger area. A click of a knob switches the page to show the graphical METARs. Text METARs and TAFs can be accessed through additional pages added to the airport listings or through clicking on highlighted airport symbols on the moving map. With the spin of a knob, you can easily check the changing METAR conditions at your destination, for example. If a TFR pops up along your route, cursor to the edge of the yellow depiction and hit the enter button to see the details, including the height of the restriction.

Although it's easy to describe the enhanced interface and weather offerings in a couple of paragraphs, you have to experience datalink weather in day-to-day flying to really appreciate how much value it brings to every flight. The $1,500 WAAS upgrade price is worth it for the better weather products alone.

Get your Ginsu knives

As they say on late-night TV infomercials, "But wait, there's more!" The WAAS upgrade also allows you to fly 4,000 existing instrument approaches with helpful vertical guidance, plus 700 new WAAS approaches. In addition, the FAA is adding 300 new WAAS approaches a year. You'll recall that the original generation of approach-capable GPS receivers allowed you to perform only nonprecision approaches, often with "dive and drive" step-down fixes, which can be challenging to manage in instrument conditions while being pelted by rain and pummeled by turbulence. The enhanced GPS signal provided through WAAS and the greater computing horsepower in the box allows the receiver to generate an advisory glideslope depiction for a standardized, less confusing approach to the runway at airports where these GPS approaches have been given the new "RNAV" title. Even with the vertical guidance, minimums for the original GPS approaches don't change, but it certainly makes for an easier flight. For those approaches that carry LNAV/VNAV (referring to lateral navigation/vertical navigation) or LPV decision altitude minimums, the enhanced WAAS signal and glideslope can allow for lower minimums, although not always. (For a complete discussion of the different types of WAAS approaches, see "License to Learn: Glideslopes Galore," page 50.)

You can get WAAS capability two ways: Buy a shiny new 430W or 530W from your favorite avionics shop or have said shop send your current 430 or 530 — smudgy screen and all — back to Garmin, where it will within a couple of days swap out the creaky old processor for a new one, drop in a new faster GPS receiver, and send it back — sans smudges — along with a new GPS/WAAS antenna. Garmin began offering the guaranteed $1,500 WAAS upgrade several years ago and tens of thousands of customers bought in. As it turns out, the upgrade was significantly more complex (read: expensive and longer in development) than Garmin anticipated, but to its credit it is sticking to the guaranteed price and delivering a fast turnaround to boot.

For some lucky customers, the upgrade is nearly a plug-and-play affair, with the upgraded box sliding right back into the same tray. Then the avionics shop lifts off the old antenna and drops in the new one. Do the paperwork, write the check, and you're done. You might get out the door for as little as $600 above the Garmin upgrade price.

However, for some of us who apparently don't live right, it gets a bit more complicated. The WAAS upgrade requires a higher quality of cable between the antenna and the receiver than the basic GPS. If you have the lower-grade cable, the shop will need to run new wiring. Fortunately, the forward-thinking folks at Lancaster Avionics in Lititz, Pennsylvania, ran the higher-grade cable a number of years ago when my 530 was installed, so I escaped that expense. But as with most pre-1984 Beechcraft Bonanzas and Barons as well as some other models of aircraft, my Bonanza needed a new annunciator panel to show five messages directly in front of the pilot. Under the previous installation methods, annunciating the messages on the unit itself was good enough. But now the FAA says the messages must be presented within the line of sight of the pilot.

Your shop can tell you whether your airplane will need the additional lights. Basically, if the left edge of the Garmin bezel is less than 11.8 inches from the centerline of the pilot's primary view — an imaginary line through the primary instruments in front of the pilot — no annunciators should be required. If the distance is between 11.8 and 13.8 inches, only two annunciators may be required. If it's more than 13.8 inches, you'll need five annunciators. If you need the annunciators, expect to spend $600 or more for the lights themselves, plus additional labor hours for the installation.

For these more complicated installations, especially if the interior must be removed to run new cables, expect the total labor bill including annunciators to top out at between $2,000 and $4,000 — more if you fly a pressurized airplane and certainly more if you have two units to upgrade. If you choose to upgrade only one of your two units, just know that the cross-fill feature, which allows the two units to share flight-plan information, will no longer work.

If you have certain models of Sandel, Honeywell Bendix/King, Avidyne, and some other brands of electronic horizontal situation indicators and primary flight displays, you will need software and/or wiring changes to show the WAAS glideslope. The software upgrades are not yet available from those manufacturers, but most say they will have them before the end of the year. The good news for those with a PFD is that you won't need the annunciators because the messages will show on the screen.

Those still using the GDL 49, Gar-min's original satellite datalink system, will need to upgrade to the GDL 69; the GDL 49 is not compatible with the WAAS units.

Finally, there are also changes necessary regarding your Jeppesen NavData updates. The new WAAS data cards are 16 MB whereas the old ones are only 8 MB, so if you have old spare cards, they are no longer usable. Also, if you use the PCMCIA Jeppesen Skybound II dataloader to download NavData updates, you'll have to upgrade to the new USB version. Regardless, you have to download a new software package to program the new cards. And you'll also have to call Jeppesen and upgrade your data subscription to include the WAAS approaches. The WAAS subscription price is higher — how much higher depends on the region you subscribe to and the method in which you receive the data.

There really is more...

So although it's not quite plug-and-play, the upgrade brings a number of enhancements that provide additional safety and convenience. Fly with a WAAS box for a while and you'll notice them gradually. For example, a new dotted line on the moving map shows the path you should fly to smoothly transition between flight-planned waypoints. Connect the box to an autopilot with GPS roll steering (GPSS) and you'll be amazed at how smoothly the autopilot flies the airplane and transitions it from one waypoint to the next. Another new feature is that with GPSS, the autopilot will now enter and then fly holding patterns with breathtaking precision. Add in an air data computer and it also will take into account winds to make sure you absolutely stay within the bounds of the depicted racetrack.

These features, coupled with the greater number of datalink weather products and better access to the weather information, and of course the more precise approaches, often with lower minimums than traditional GPS approaches, make the WAAS upgrade a valuable and worthwhile investment.

E-mail the author at thomas.haines@aopa.org.