CIRRUS DESIGN SR20, Pilot Operating Handbook

Page: 442 / 508

2 of 16 P/N 11934-S27
Section 9 Cirrus Design
Supplements SR20
Section 1 - General
This airplane is equipped with an S-TEC System 55SR Autopilot. The
System 55SR autopilot is a two-axis autopilot system. The system
consists of a flight guidance programmer/computer, altitude
transducer, turn coordinator, and primary flight display (PFD). Mode
selection is made on the programmer/computer panel. A button on
each control yoke handle may be used to disengage the autopilot. The
autopilot makes roll changes through the aileron trim motor and spring
cartridge and makes pitch changes for altitude hold through the
elevator trim motor. The autopilot operates on 28 VDC supplied
through the 5-amp AUTOPILOT circuit breaker on the Essential Bus.
The S-Tec System 55SR Autopilot features:
• Heading Hold and Command.
• NAV/LOC/GPS tracking; HI and LO sensitivity.
• Altitude Hold and Command.
• Vertical Speed Hold and Command.
• GPS Steering (GPSS) for smoother turns onto a course or
during course tracking.
Refer to S-Tec System Fifty-Five SR Autopilot Pilot’s Operating
Handbook
(POH), P/N 87127 dated 01 September 2003 or later
revision for full operational procedures and description of implemented
modes.
• Note •
The SR20 implementation of the System 55SR Autopilot does
not utilize the optional remote annunciator, roll servo, yaw
servo. Therefore, all references to these items in the S-Tec
System 55SR POH shall be disregarded. Additionally, this
installation does not utilize a CWS (Control Wheel Steering)
switch or an AUTOPILOT MASTER switch.
This installation utilizes the airplane’s roll trim actuator to
affect steering changes. Therefore, the automatic trim function
of the System 55SR is not implemented. Disregard all
references in the S-Tec System 55SR POH to this feature.
Roll information is displayed on the PFD. Autopilot Flight
Director is not implemented in this installation.
Revision 2: 07-18-05