S-tec 55x Installation Manual [top] Page

: Includes GPS Roll Steering (GPSS), Vertical Speed control, and precision approach capability (LPV, LNAV/VNAV). 2. Mandatory Installation Requirements Installation of the S-TEC 55X is governed by a Supplemental Type Certificate (STC) specific to the aircraft serial number. Certification : Installation should only be performed by FAA-certified S-TEC Dealers

Before the aircraft can be cleared for flight, a mandatory ground test procedure must be performed and documented in the aircraft maintenance logs.

The servo output arm must be perfectly aligned with the aircraft’s control linkages to prevent over-centering. S-tec 55x Installation Manual

This 42-page manual dated October 29, 2013, includes parts lists for the main wire harness, turn coordinator, pressure transducer, and servo kits.

Secure the bridle cables to the primary aircraft flight control cables using the specified clamps. Ensure the aircraft controls can move from stop to stop without the bridle cable rubbing against structural ribs. Pitch and Pitch Trim Servo Installation : Includes GPS Roll Steering (GPSS), Vertical Speed

Verify that the autopilot completely disengages when pressing: The AP DISC switch on the control yoke. The Avionics Master switch. The dedicated Autopilot Circuit Breaker. Flight Testing and Troubleshooting

The 55X features built-in GPSS converter logic. Connect the ARINC 429 transmit lines (A and B) from your GPS navigator (e.g., Garmin GTN or GNS series) directly to the designated pins on the 55X harness. Certification : Installation should only be performed by

The core installation consists of several interconnected modules:

The S-TEC 55X (System Fifty Five X) is a two-axis, rate-based autopilot designed to provide exceptional stability, tracking, and altitude control for general aviation aircraft. Known for its smooth performance and robust feature set—including heading hold, altitude hold, vertical speed command, and GPS/NAV tracking—the 55X is a popular upgrade.

The S-TEC 55X requires clean, shielded wiring to interface with external navigation sources, such as GPS navigators, EFIS displays, and HSI systems. Primary Power and Grounding