Using VNAV on an Approach

One of the terrific features available in the latest digital autopilots is VNAV, or vertical navigation. If you have a Garmin GTN-series navigator and a GFC 500 or GFC 600 autopilot, you can use VNAV to descend to the charted altitudes along the intermediate legs of an instrument approach, until you reach the final approach fix.

This 10-minute video demonstrates how VNAV can help you fly a smooth, precise descent prior to the FAF. The video explains the basic concepts, uses the Garmin PC Trainer Suite to highlight key details, and then shows VNAV at work as I fly the RNAV (GPS) RWY 12 approach at Kelso, WA (KKLS).

[JJ-kzzq]

I've been learning about VNAV functionality through videos like yours, and this is a really good one. Thanks for walking through all the details and the Garmin trainer!

[jordan]

Very nice video. I just got an upgraded panel with G600txi / GTN750xi and GFC600 in my TBM700. I flew a test approach "old school" with the step downs and came home knowing there was a better way.... VNV + APR :) Wonderful.

[blflyfish]

Another excellent instructional video, Bruce. Thank you!

[Kevlux]

I’m about to head out and do this same approach in my 1960 Comanche 250! I just got dual G5’s, a 650xi, and a GFC-500 installed and will probably be making plenty of stops at Kelso, while I’m based at Pearson - KVUO. Thanks for the video!

[YourFriendlyGApilot]

Super helpful, thank you!
To make sure I'm getting it right: i could set VNAV to do the initial part of the approach and then, once i hear something like "maintain XXXft until established, cleared approach" i would ALSO press APR so the VNAV brings me to the FAF&GP and there switches by itself? (Note: i am thinking of GFC500+GTN650xi).

Again, thank you, really helpful video.

[LakesideAcres]

How did you get the GFC in the trainer? I only see options for GTN and a display.

[PhoenixSkyAviation]

What is the name of the panel with the heading, altitude, baro knobs. Is That an additional panel to the autopilot?

[tammaramma]

Hi Bruce, what about using VNAV for the stepdown fixes on an non-precision approach? If I'm not mistaken the GFC-500 will descend to the appropriate altitudes as long as it's in the flight plan correct? Or do you have to re enter the altitude after passing each fix for the new fix. I haven't seen any videos on using VNAV for a non precision GPS approach (eg. KDLS RNAV (GPS)-A).

[guarita]

What does that cyan polygon around the aircraft on the map at 3:46 mean?

[mehall]

How or where did you get the GFC autopilot controller for the Garmin trainer?

[Jebusite]

Is VNAV for VFR flights or IFR flghts?

[lucabencini]

"If you have a Garmin GTN-series navigator and a GFC 500 or GFC 600 autopilot, you can use VNAV to descend to the charted altitudes along the intermediate legs of an instrument approach, until you reach the final approach fix."


This is not true with the GFC 500. With the GFC 600, VNAV will take the airplane to the point of GP/GS intercept. This will also allow having two armed vertical modes: GP/GS and ALTV. (GP/GS is achieved by selecting APR mode.) GFC 500 will take you to a fix prior to GP/GS intercept.

Why? In the GFC 500, Transition to Approach is not enabled in the configuration mode in the GTN XXX; it is enabled in the GFC 600. I asked Garmin why: “it requires additional testing and proper documentation”. I did offer my Mooney with the GFC 500 for “testing” but at this time, a very low priority for Garmin.

[AircraftWings]

Thank you. Very good video to learn from. Until my flight yesterday I thought altitude bug had to be set to MDA/DA in order for GFC-500/600 to descend in VNAV/APP mode. Flew the KAST RNAV 26 Approach where GFC500 flew below my altitude bug in VNAV (forgot to set bug to MDA/DA). I was quite surprised it still descended. Again, thank you.