Vflite, left, and GPS Trainer offer interactive ûGPS training from the desktop.

Back in the dark ages, when IFR GPS first hit the streets, Garmin took a terrific beating in the press—and among some customers—for its cumbersome GPS 155 operating logic. In reality, the navigator was learnable but it took effort. The company is still smarting from the dubious experience of being a “pioneer” in certified GPS, although the sale of shiploads worth of GNS430 has helped them get over it.

Garmin and the other GPS makers learned bitter lessons about jollying a new piece of gear through the FAA certification process. Lesson one: the FAA’s often arcane and capricious suggestions for operating logic might or might not work. If they don’t work,…