Cirrus SR22 User manual

CIRRUS AIRPLANE MAINTENANCE MANUAL MODEL SR22
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SYSTEM THIRTY AUTOPILOT
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.
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CIRRUS AIRPLANE MAINTENANCE MANUAL MODEL SR22
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2. TROUBLESHOOTING
Trouble Probable Cause Remedy
Unexpected flight characteristics
with autopilot engaged.
Moisture in static traps and/or
sump.
Check traps and sump for mois-
ture. Blow out lines.
Moisture in static line. Check lines for moisture. Perform
System Test - Static Plumbing
System (Refer to 34-10).

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3. MAINTENANCE PRACTICES
A. Turn Coordinator/Roll Computer (See Figure 22-102)
(1) Removal - Turn Coordinator/Roll Computer
(a) Set BAT 1, BAT 2, and AVIONICS master switches to OFF positions.
(b) Pull TURN COORDINATOR circuit breaker.
(c) Remove LH kick plate. (Refer to 25-10)
(d) Disconnect instrument light connector and cable assembly from back of turn coordinator/
roll computer.
(e) Remove set screw from multi-function knob and remove knob.
(f) While supporting turn coordinator/roll computer, remove screws and washers securing
unit to instrument panel.
(g) Remove turn coordinator/roll computer from airplane.
(2) Installation - Turn Coordinator/Roll Computer
(a) Position turn coordinator/roll computer in instrument panel and install screws and wash-
ers.
(b) Connect connector and cable assembly.
(c) Install LH kick plate. (Refer to 25-10)
(d) Reset TURN COORDINATOR circuit breaker.
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CIRRUS AIRPLANE MAINTENANCE MANUAL MODEL SR22
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B. Pitch Computer (See Figure 22-102)
(1) Removal - Pitch Computer
(a) Set BAT 1, BAT 2, and AVIONICS master switches to OFF positions.
(b) Pull AUTOPILOT circuit breaker.
(c) Remove MFD. (Refer to 31-60)
(d) Disconnect cable from pitch computer.
(e) Remove screws, washers, and nuts securing pitch computer to console.
(f) Remove pitch computer from airplane.
(2) Installation - Pitch Computer
(a) Align pitch computer over mounting holes. Ensure data connector is pointed aft.
(b) Install screws, washers, and nuts attaching pitch computer to console.
(c) Connect cable assembly.
(d) Install MFD. (Refer to 31-60)
(e) Reset AUTOPILOT circuit breaker.

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C. Altitude Transducer (See Figure 22-102)
(1) Removal - Altitude Transducer
(a) Set BAT 1, BAT 2, and AVIONICS master switches to OFF positions.
(b) Pull AUTOPILOT circuit breaker.
(c) Remove MFD. (Refer to 31-60)
(d) Disconnect cable from altitude transducer.
(e) Disconnect static line from altitude transducer.
(f) Remove screws and washers securing altitude transducer to console rib.
(g) Remove altitude transducer from airplane.
(2) Installation - Altitude Transducer
(a) Align altitude transducer over console rib mounting holes and secure with washers and
screws.
(b) Connect static line to attitude transducer.
(c) Connect cable to altitude transducer.
(d) Perform Pitot System Leakage Test. (Refer to 34-10)
(e) Perform Static System Leakage Test. (Refer to 34-10)
(f) Install MFD. (Refer to 31-60)
(g) Reset AUTOPILOT circuit breaker.
D. Autopilot Disconnect Switch
The autopilot disconnect switch is integral to the control yoke. For maintenance practices pertinent to
the control yoke, see Flight Controls. (Refer to 27-10)
E. Altitude Hold Switch - Serials 0002 thru 2036, 2038 thru 2042
The autopilot hold switch is integral to the control yoke. For maintenance practices pertinent to the con-
trol yoke, see Flight Controls. (Refer to 27-10)
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F. GPSS 429 Converter (See Figure 22-102)
(1) Removal - GPSS 429 Converter
(a) Set BAT 1, BAT 2, and AVIONICS master switches to OFF positions.
(b) Disconnect battery. (Refer to 24-30)
(c) Remove glareshield. (Refer to 25-10)
(d) Disconnect electrical cables from GPSS 429 converter.
(e) Remove screws, washers, and nuts securing GPSS 429 converter to wire loom.
(2) Installation - GPSS 429 Converter
(a) Install screws, washers, and nuts securing GPSS 429 converter to wire loom.
(b) Connect electrical cables to GPSS 429 converter.
(c) Install glareshield. (Refer to 25-10)
(d) Connect battery. (Refer to 24-30)

CIRRUS AIRPLANE MAINTENANCE MANUAL MODEL SR22
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G. Remote GPSS Switch (See Figure 22-102)
(1) Removal - Remote GPSS Switch
(a) Set BAT 1, BAT 2, and AVIONICS master switches to OFF positions.
(b) Disconnect battery. (Refer to 24-30)
(c) Remove glareshield. (Refer to 25-10)
(d) Remove screws securing GPSS switch to instrument panel.
(e) Disconnect electrical cable from back of GPSS switch and remove switch from airplane.
(2) Installation - Remote GPSS Switch
(a) Connect electrical cable to back of GPSS switch.
(b) Install screws securing GPSS switch to instrument panel.
(c) Install glareshield. (Refer to 25-10)
(d) Connect battery. (Refer to 24-30)
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CIRRUS AIRPLANE MAINTENANCE MANUAL MODEL SR22
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Figure 22-101
System Thirty Schematic
ROLL TRIM CARTRIDGE
VOR/LOC
ALTITUDE TRANSDUCER
PITCH COMPUTER
TURN COORDINATOR / ROLL COMPUTER
PITCH TRIM SERVO
SR22_MM22_1551

CIRRUS AIRPLANE MAINTENANCE MANUAL MODEL SR22
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Figure 22-102
System 30 w/ GPSS Installation
SR22_MM22_1552A
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LEGEND
1. Screw
2. Washer
3. Pitch Computer
4. Cable
5. Nut
6. Remote GPSS Switch
7. GPSS Converter
8. Adjustment Screw
9. Turn Coordinator / Roll Computer
10. Connector
11. Cable Tie
12. Static Line
13. Connector Nut
14. Nylon Insert
15. Tee
16. Altitude Transducer
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CIRRUS AIRPLANE MAINTENANCE MANUAL MODEL SR22
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