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Aviation Alerts and Advisories

Service Advisory 21109 Rev B: GTN Xi May Not Provide Roll Steering When Smart Glide Is Activated From OBS Mode


Added Resolution


Garmin GTN Xi Series products (with Software Version 20.20 or later) in OBS mode with Smart Glide™ enabled and interfaced to any of the following are affected:

    • Garmin autopilot
    • Third-party autopilot capable of following GPS roll steering (including GPSS heading emulation)
    • G500/600 TXi PFD (displaying the roll steering indicator)


If Smart Glide is activated while GTN Xi is in OBS mode, the GTN Xi will not provide roll steering for the autopilot to follow the Smart Glide route to the destination airport.


Prior to activating Smart Glide, turn off OBS mode. If Smart Glide is activated while in OBS mode, promptly deactivate and reactivate Smart Glide.

The Smart Glide route will still be displayed on the map and all related indications are correct. The problem presents itself as the autopilot continuing to fly straight along the previous OBS course rather than turning the aircraft toward the destination airport and following the Smart Glide route. For customers with a G500/600 TXi PFD without a flight director, manually following the magenta roll steering indicator will also result in continued flight along the previous OBS course.


This has been fixed in GTN Xi Software Version 20.23.

Service Advisory 21109 Rev B