Cirrus SR20 Pilot Operating Handbook page 358

Section 9 Cirrus Design
Supplements SR20
Roll and Pitch Servo
The Roll Servo, located below the passenger seat, and the Pitch
Servo, located below the baggage compartment, position the aircraft
flight controls in response to commands generated by the Integrated
Avionics Units Autopilot calculations.
28 VDC for Roll and Pitch Servo operation is supplied through the 5-
amp AP SERVOS circuit breaker on MAIN BUS 1.
Integrated Avionics Units
The Integrated Avionics Units located behind the MFD and instrument
panel, function as the main communication hubs to the Avionics
System and GFC 700, linking the systems to the PFD and MFD
displays. Each Integrated Avionics Unit receives air and attitude data
parameters from the Air Data Computer and Attitude and Heading
Reference System. Each Integrated Avionics Unit contains a GPS
WAAS receiver, VHF COM/NAV/GS receivers, and system integration
microprocessors. The AFCS function within the Integrated Avionics
Units control the active and armed modes for the Flight Director, as
well as Autopilot engagement. The Flight Director commands for the
active modes are calculated and sent to the PFD for display and mode
annunciation. The sensor data and Flight Director commands are also
sent to the servos over a common serial data bus.
28 VDC for Integrated Avionics Unit 1 operation is supplied through
the 7.5-amp COM 1 and 5-amp GPS NAV1 circuit breakers on the
ESS BUS 1. 28 VDC for Integrated Avionics Unit 2 operation is
supplied through the 7.5-amp COM 2 and 5-amp GPS NAV2 circuit
breakers on the MAIN BUS 2.
Autopilot Disconnect Switch
The yoke mounted Autopilot Disconnect (AP DISC) Switch
disengages the Autopilot and may also be used to mute the aural alert
associated with an Autopilot Disconnect.
For ESP equipped aircraft, the Autopilot Disconnect Switch will also
temporarily suspend the servo's from providing ESP correction forces,
thus having an "interrupt" function. This may be useful to alleviate
control forces if intentional maneuvers are necessary beyond ESP's
engagement threshold (i.e., isolated training maneuvers).
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Revision 03: 09-08-14