Rudder Reference and an SPX

[Orlando]

The following is an unpublished feature of the SPX Autopilot Course Computers:

If the SPX Autopilot Course Computer is powered up and the rudder reference transducer (RR) is hard over, the autopilot will ignore the RR. The RR is +/-55 degrees when not hooked up and the RR indicator on my ST70 is only +/-30 degrees. So when you power up the system the RR must be within the +/-55 degrees in order for the unit to use the RR, and really should be within +/-30 degrees for proper display.

This is normally not an issue if properly installed first, but if testing prior to installing this is really important, as the RR is spring loaded and will always be hard over past the 55 degree point and will cause the SPX to ignore the RR. So you must hold the RR in the middle in order for it to power up correctly and be seen.