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Roll Centering

Since all S-TEC autopilots are Rate Based, the interface with the rate gyro (Turn Coordinator) must be set properly. This is known as Roll Centering. The adjustment for Roll Centering is performed at system installation, after the replacement of a turn coordinator, programmer, or roll computer, or any time symptoms of centering offset appear.

These symptoms include:
The heading bug is offset from the Lubber Line when tracking in Heading Mode.
The STB knob is offset when in level flight in System 40/50 installations.
Tracking occurs with needle offset or with the needle lost to one side in NAV (Soft) mode.
Needle deflection in NAV mode causes a greater servo response to one side than the other during the ground check.

If in the course of the normal operation of your autopilot you see any of these symptoms, we recommend taking your aircraft to your S-TEC dealer to have the Roll Centering adjusted. The adjustment is straightforward and your accurate description of the symptoms will help the dealer make this adjustment rapidly. With the Roll Centering performing as designed you will enjoy the flight performance of your S-TEC System even more.

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