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GPS Who Needs It?

With this simple easy-to-read electronic marvel,
aircraft navigation moves into the 21st Century

Like many of my older fellow pilots who have flown many years without a lot of fancy electronic navigation equipment, I saw no need to spend more money on radios in my C-172. True, I wasn't happy that they all weighed too much, no longer worked reliably, and continued to cost too much for repairs.

My wife and conscience asked if I really needed a new navigation gadget after 36 years of flying successfully with radios which never did all work at the same time. What to do? Spend money fixing up my original 1967 Cessna Nay/Corn VOR's and ADF, or remove them all and move into the 21st Century?

The barrage of articles and advertising in the magazines about the new Global Positioning System (GPS) got me thinking. Here was a portable system that could replace the VOR, ADF and DME in the airplane. Sounds too good to be true, but why not investigate further?

Unclear as to if and what to buy, I asked Claude Leblanc of V.I.P. in St. Hubert, COPA's official supplier of aviation products, to loan me a demonstrator unit of whatever he was selling most. For starters, he graciously loaned me a Garmin GPS 55 AVD for my evaluation.

GPS unit in use
Although the GPS unit is usually yoke-mounted, writer Hofmann found this panel mounting arrangement to be quite convenient.
Out of the box and onto my kitchen table with this new marvel. The instruction book and all the buttons could baffle a noncomputer whiz like me. However, I have a defence mechanism which keeps that me from reading instructions unless absolutely all else fails, allowing me to learn at my own relaxed pace - or so my rationale goes.

It took me about an hour of pushing buttons and getting all sorts of neat displays successfully on the screen to realize that the unit was ready to go as is. All I had to do was punch the "GO TO" button and then respond to the machine's question of "WHERE TO" by putting in the destination identifier, found in the VFR Supplement. Bingo! Indeed, the short book of instructions says just that - for those who will read instructions.

Out to my trusty old 1967 C-172. Instead of using Garmin's quick and simple yoke mount, I mounted the unit with two screws on the instrument panel and over the holes left by the removal of an unserviceable VOR head and an ADF indicator. Power was from the cigarette lighter in the airplane. The antenna was suction-cupped to the inside bottom of the windshield. It can hardly be seen, and it did not change the compass correction on my plane.

An hour later I was airborne and using the unit with two other pilots on board, one of whom flew the airplane while I played. All features were tested, and now I was more impressed than ever. The world was there at the push of a button. No crystal ball is required, either, to see that the GPS would soon be the preferred method of flying IFR. Indeed I hear from pilot friends that some jet pilots are already flying by utilizing a GPS perched on top of their instrument panels, cross-referencing their Omega and other systems with the GPS.

It has been my experience that all the advertising about the genie in this little box is true. There isn't any more information a pilot could need. The GPS gives all information a VOR, an ADF and a DME provide - and all on a single screen which at night is more readable than any of the other instruments for my old bifocalled eyes. Because the unit gives both track and bearing, the function of an ADF is served - even better since the ADF station does not need to be a transmitter but could be your destination. The unit simultaneously also works like a VOR, complete with course deviation indicator and DME. And having constant groundspeed readout is handy because it permits the pilot to climb to an altitude where the wind component is most favorable. Incredibly, all this information is displayed on one small but very readable screen.

Not mentioned in the brochures, but something I found very important, is that with the information so accurate and available at a glance, the VFR pilot is now provided with a means of navigating which allows her/him to keep the eyes outside the cockpit where they belong, particularly in poorer visibility. No longer must you go back and forth between map and ground, wondering if you have correctly identified a landmark. As well, although there is always the concern about potential equipment failures, the fact is that if one were to lose the GPS, you would be able to proceed navigating from a very accurately known last position and heading.

The GPS system mounted on the panel
GPS unit is mounted over holes left by removal of VOR head and ADF indicator.
Very novel, and very convenient too, is the fact that you can now punch in your complete route for a trip in the comfort of your home. When the day of the flight arrives you clip your GPS into the airplane, turn the power on, select your route, and the unit takes care of the rest.

If you are concerned about running down the batteries while you are mastering the intricacies or flight planning, you can plug the unit into the cigarette lighter of your car and use the car's electrical power while you play, learn or flight plan. I was convinced that this was the system for me. What more could a navigator want? I could get rid of all my intermittent navigation aids in the airplane and replace them with this one very agile box. The trial with GPS was complete, or so I thought, and I was ready to buy a unit.

But then Claude introduced me to Garmin's latest creation, the 95 AVD, which miraculously provided even more new navigational goodies. This was truly 21st Century stuff. For starters, it offered up to 30 programmable legs for any one of 20 routes, vertical navigation capability, density altitude calculation - and incredibly, a complete Jeppesen database of all airports, VORs, NDBs, and intersections, comm frequencies and runways, a diagram of which can be called up on screen at the push of a button.

But perhaps the two most valuable features of this new unit, from my point of view, were a moving map display whose scale can be changed, and the lettering which appears larger than on the 55 model. The map gives the pilot a good overall picture of the aircraft's position and permits calling out any particular point to retrieve information about it. Cleverly thought out by the Garmin folks, the 95 even fits the 55 mount so that all I had to do was swap units in my airplane.

As with the earlier model, I found it hard to imagine what other information a pilot could want in navigating an airplane - bearing, track, ground speed, ETE, ETA, fuel remaining calculator, local sunset times, a data base with all airport locations, VORs, NDBs and intersections already stored ready for recall, and airport diagrams of all airports in the VFR Supplement! This little box is sheer magic for the aviator.

But it represents even more. Finally we pilots can buy a piece of equipment which can serve not only the airplane, but is portable into a boat or a snowmobile, for example. Outdoorsmen and cross-country skiers can use the unit to advantage. Interesting is that already many of the ultralight fliers have taken to the GPS. Here we have the simplest of airplanes with the most sophisticated of equipment while we who fly 'standard' airplanes have heavy power-hungry stacks of ill-working and maintenance-heavy radios. Low-level navigation, the kind ultralighters have to practice when flying, has never been easy. Now the ultralighters have a unit in which they can store up to 500 of their own waypoints (friends' farms, fishing holes, etc.), so they can readily visit each other or return to their favorite unmarked landing areas with simple accuracy.

Some of us like to go airport visiting, either by plane or car. Imagine driving along and saying to yourself, I wonder where the nearest airport is? A push of a button and the GPS lists the nine nearest airports - distance and direction Won't your passengers love that?

Since being wooed and won by this latest GPS marvel, my airplane is undergoing a restoration. Not only is it lighter now, with outdated and electrical power-hungry equipment gone, but I feel I am safer in the air with better and more instantly available information.

I may even read the manual someday to explore the remainder of its possible features. This one is a keeper. *

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Frank Hofmann
Copyright © 1993