S-Tec 40 Autopilot Roll Centering Results

Results of roll centering (calibrating) the STB, HDG and NAV modes of an S-Tec 40 autopilot in a Cherokee 140 using DG heading bug, VOR CDI and GPS CDI. Power to autopilot was turned off and back on between calibrations of each mode. Calibration process consisted of turning a recessed potentiometer screw in the direction of the desired correction for a given mode.