Something Can Be Done

The promise of Area Navigation (RNAV and GPS) was that it would be a simpler and more accurate way to navigate than older styles of navigation and to a great extent, that promise has been realized. GPS accuracy, especially when augmented with WAAS, is very good indeed. As for simplicity ... not so much. Waypoint navigation was a revolutionary concept when it was introduced, but it has been integrated with existing navigational paradigms and infrastructure in an evolutionary manner, not unlike the way an artist might sculpt clay or mold papier-mâché. This evolutionary approach has created some unfortunate and unforeseen complexity, but it doesn't need to be that way. Mom always said "Don't complain unless you can offer a solution or a suggestion," so here are my top five recommendations for simplifying the world of RNAV.

Wayward Waypoints


Many airports out there have a VOR located at airport and in those cases the VOR and the airport have the same name. Just as often the VOR may be some miles away from the airport, but both still have the same name. At the heart of every GPS receiver is a computer running software and software doesn't tend to handle ambiguity very well. That's why the GPS database encodes airports using a four-character ICAO identifier and VORs with a three-character identifier. The FAA's charting division could do us a big favor by using four-character ICAO airport identifiers on their chart products, but they don't. If they did, it would be crystal clear to student pilots and budding instrument pilots that KSAC refers to the surveyed center of the Sacramento Executive airport while SAC refers to the Sacramento VOR. 

Not in Kansas Anymore

The first step in GPS navigation is to enter the name of a VOR or NDB station on the ground, the name of an intersection of two VOR radials, an airport ID (which represents the surveyed center of the airport), a charted VFR reporting point, a Computer Navigation Fix defined by FAA chart designers, or even a user waypoint that you've created. The AIM refers to this type of navigation as to-to, not to be confused with Toto, the little black terrier in theWizard of Oz. GPS receivers only navigate to one waypoint at a time, also known as the current waypoint.

GPS makes it simple to navigate to a waypoint and most receivers provide a moving map display, which is a score for simplicity and safety. The bad news is that unless you're lucky enough to have a keyboard as part of your GPS receiver, entering a waypoint requires a precise and often convoluted sequence of knob-turning and button-pushing. A bad user interface makes it all too easy to misspell the name of the waypoint: Get just one letter wrong and instead of navigating to a VOR that is 20 miles away, you may be headed to Tierra del Fuego by mistake!

The engineers that designed GPS receiver user interfaces didn't set out to create difficult-to-use products, but the fact is they did. Whether it was the desire to save a few bucks by having fewer knobs and buttons or simply a race to get a product to market, it's clear that mistakes were made. Now the users of these products have to live with the mistakes and to quote Warren Zevon, "… it ain't that pretty at all." Bad UI design is the Achilles heel of GPS and many of us pilots have become so acclimated to these convoluted interfaces that we have lost sight of just how whacked this situation is.

Near the top of my "need to fix" list is Garmin's Small-Knob/Big-Knob interface. You press the small knob to enter "cursor mode" so you can edit or enter the name of a waypoint in a flight plan. You turn the small knob to start the process of entering letters and then the small knob changes function. Whoa there! A knob whose function changes depending on an interface context that is mostly invisible to the user? This needs to be fixed and one simple way would be a separate button dedicated to starting and ending the waypoint editing mode.

Having a separate button for edit mode would also fix the problem that countless new Garmin users run into: Pressing the small knob to exit cursor mode and accept whatever changes they have made. Having watched hundreds of pilots make this mistake thousands of times it's clear that a common intuitive belief is that if you press one button or key to enter a mode, pressing the same button or key should exit that mode. In the Garmin world, this simply exits the editing mode and, here's the amazing part, destroys whatever changes you made without asking you to confirm that's what you want to do. This is B-A-D.