S-tec 55x Installation Manual !!install!! Official

The S-TEC 55x is a legendary name in general aviation. Known as a "digital system with analog backup," this rate-based, two-axis autopilot (with optional yaw damper) represents a gold standard for aircraft like the Piper Seneca, Cessna 182, Beechcraft Bonanza, and many other high-performance singles and twins. However, the difference between a reliable, safe autopilot and a persistent in-flight headache lies entirely in one document: the .

Lay out all components. Verify the servo part numbers match your aircraft’s control forces (e.g., SV-35 for heavy twins). S-tec 55x Installation Manual

| Pin | Signal | Function | Wire Gauge | |------|----------------------|-----------------------------------|-------------| | 1 | GND (Power) | Chassis ground | 18 AWG | | 3 | +14V or +28V | Aircraft power (through CB) | 18 AWG | | 12 | NAV/GPS Valid | Input from GPS (active high) | 22 AWG | | 14 | Heading Bug CW | Potentiometer wiper | 22 AWG shielded | | 27 | Pitch Servo CW | Motor drive output | 20 AWG | | 38 | Yaw Rate (Gyro) | Analog voltage (1.5V +/- 0.2V at level) | 22 AWG shielded | The S-TEC 55x is a legendary name in general aviation