EASA SIB AIR-22-07: Avidyne Corporation DFC90 Autopilot System

What to do

Owners and operators of aircraft with the affected Avidyne DFC90 autopilot, PFDs, and Garmin navigators should review Avidyne Service Information Letter 606-00170-004, Revision 00, dated December 14, 2021, and follow the recommended user actions outlined therein. They should coordinate with Avidyne technical support for software updates or guidance. No specific compliance deadline is stated in the bulletin.

Summary

The Special Airworthiness Information Bulletin SAIB: AIR-22-07 is an FAA informational bulletin addressing a potential autopilot anomaly in aircraft equipped with the Avidyne Corporation DFC90 autopilot system, Avidyne primary flight displays (PFDs), and Garmin GNS430/530W or GTN650/750 navigators. The issue involves an uncommanded turn to heading 360 during a non-degradable LPV approach if SBAS, EGNOS, MSAS/QZSS, or GAGAN WAAS reception is lost. This bulletin applies specifically to Avidyne DFC90 autopilots with software part number 510-00874-000 Rev03 or earlier and Avidyne PFDs with software part number 530-00214-002 Rev06 or earlier.

What changed

This bulletin introduces awareness of a specific anomaly where the Avidyne DFC90 autopilot may make an uncommanded turn to heading 360 during certain GPS signal losses in LPV approaches. It identifies the affected software versions and hardware configurations and references Avidyne's Service Information Letter 606-00170-004 for mitigation. No mandatory airworthiness directive action is proposed at this time.

Why it matters

This information is critical for aviation professionals operating or maintaining aircraft with the affected Avidyne autopilot and Garmin navigators, as the anomaly could impact flight path control during precision approaches. Understanding this issue helps operators and maintenance teams mitigate risks and maintain safe autopilot operation. Compliance teams should be aware that no AD is currently required but should monitor for updates.