Pilots of GA piston singles don’t typically fly STARs, and usually ATC vectors us to join approaches that don’t require many step-downs as we intercept the final approach course. Instead, we tend to use the VNAV (or older VCALC) features in our avionics to meet crossing restrictions, manage the descent from cruise to an initial altitude for an approach, or to help us arrive near an airport at the appropriate traffic pattern altitude.
But when connected to a GPS navigator, such as a Garmin GTN 750 or 650, that supports vertical navigation, new digital autopilots like the Garmin GFC 500 and GFC 600 can automatically descend as you fly the initial legs of an instrument approach, reducing your workload and helping you spend more time monitoring your progress.
To watch VNAV fly a series of published step-downs, join me as I fly the RNAV (GPS) RWY 29 approach at the Skagit Regional airport (KBVS) north of Seattle, an approach that shows the value of using VNAV. I’m in my Beechcraft A36 equipped with the GFC 600 autopilot, a GTN 750Xi, and G500 TXi.
For more information about VNAV, see these additional posts here at BruceAir: