S-tec 55x Installation Manual (2025)

Probable Cause : Bridle cables are too loose, or the turn coordinator is loose in its panel cutout.

for service bulletins that supersede the manual. For example, Service Bulletin SB-55x-014 changes the rate gyro warm-up time from 3 to 5 minutes.

Installing this autopilot requires compliance with FAA AC 43.13-1B and AC 43.13-2B. S-tec 55x Installation Manual

Mechanical failures are the leading cause of post-installation autopilot issues, such as binding or slipping controls. Servo Mounting and Brackets

Engage HDG and ALT mode. The aircraft should stabilize within +/- 20 feet and hold headings without "snaking." Probable Cause : Bridle cables are too loose,

Before beginning any physical work, a thorough review of the aircraft’s current configuration and the specifics of the S-TEC 55X system is essential. The 55X is more than just a computer; it integrates with several aircraft systems to provide full functionality. A typical installation includes a flight guidance programmer/computer, an altitude encoder, an altitude selector/alerter, a turn coordinator, and a Heading System (DG or HSI).

Before cutting metal or running wires, technicians must verify the specific installation eligibility for the target aircraft. 1. Supplemental Type Certificate (STC) Documentation Installing this autopilot requires compliance with FAA AC 43

Set the aircraft control surfaces to the absolute neutral position. Center the servo output arm.

During the installation process, there are several key considerations to keep in mind:

: Manually override the autopilot by forcing the control wheel against the engaged servo. The internal servo slip clutch must slip smoothly without binding or requiring excessive human force. 3. Safety Disconnect Checklist

: Typically mounted in the wing or floor structure.