GFC 500 systems installed per STC SA01866WI in the following Piper aircraft are affected:
FAA STC SA01866WI
Optional: This STC Service Bulletin may be incorporated at the owner’s discretion.
STC SA01866WI Master Drawing List, GFC 500 Autopilot with Electronic Stability and Protection Part 23 AML STC, Rev. 46 includes instructions to enable Vertical Speed Inertial Gain. Vertical Speed Inertial Gain improves autopilot altitude hold performance in aircraft that do not have a static system coupled to fuselage mounted static ports.