Cirrus SR22 Maintenance Manual

C I R R U S
A I R P L A N E M A I N T E N A N C E M A N U A L
1. DESCRIPTION
The S-TEC System Thirty is a dual axis autopilot system that provides roll stability, heading hold, NAV/
GPS tracking capabilities, and altitude hold capabilities controlled via the roll-trim cartridge and pitch trim
servo. (See Figure 22-101)
The system components consist of an electric turn coordinator/roll computer, altitude transducer, pitch
computer, and an HSI or DG for heading hold. Roll axis information is sensed by the turn coordinator gyro.
Pitch axis information is sensed by the pitch axis computer. Heading information is provided to the autopilot
by the HSI or DG. The operating controls for the S-TEC System Thirty Autopilot are located on the turn
coordinator/roll axis computer mounted on the instrument panel.
The Multi-function Control Knob is a rotary knob with an integrated push-button feature. The rotary function
or the knob controls the turn command. Depressing the control knob allows the operator to highlight and
scroll through the system modes.
Roll Stabilization Mode is active when "ST" is illuminated. Wings are held level and the Turn command
knob is activated for autopilot commanded turns up to 90 percent standard rate.
Nav/GPS Track Mode is active when "LO" or "HI" is illuminated. The "LO" and "HI" lights indicate system
gain levels. Dependent on the navigational aid used, the operator selects the appropriate gain level.
Heading Hold is active when "HD" is illuminated. Heading Hold is facilitated by the HSI to provide heading
information to the system
Serials 0002 thru 2036, 2038 thru 2042: The Autopilot Disconnect Switch is integral to the 4-way trim
switch on the control yoke. To disengage the autopilot depress the 4-way trim switch or depress and hold
the multi-function control knob for approximately 3 seconds.
Serials 2037, 2043 & subs: To disengage the autopilot depress the Autopilot Disconnect Switch or depress
and hold the multi-function control knob for approximately 3 seconds.
Altitude Hold is engaged by a switch on the control yoke and is active when "ALT" is illuminated. Flight alti-
tude data is derived by the pressure transducer and relayed to the pitch computer to provide altitude hold.
EFFECTIVITY:
All
SYSTEM THIRTY AUTOPILOT
M O D E L S R 2 2
22-10
Page 1
15 Apr 2007