Cirrus SR20 Maintenance Manual

Type
Maintenance Manual
CIRRUS AIRPLANE MAINTENANCE MANUAL MODEL SR20
34-20
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EFFECTIVITY:
ATTITUDE AND DIRECTION
1. GENERAL
This section contains information pertaining to those portions of the system which use magnetic, gyro-
scopic, and inertia forces. Included is the magnetic compass, attitude indicator, and magnetometer. (See
Figure 34-001)
A. Magnetic Compass
The magnetic compass, mounted to the fuselage above the windshield, contains a circular compass
card, visible through the compass case window, suspended in alcohol solution. The compass is
equipped with compensating magnets and has two adjusting set screws, one for North-South adjust-
ment and one for East-West adjustment. These set screws are located behind the access plate on the
compass face. Light is integral and controlled by the instrument light rheostat on the bolster switch
panel.
B. Attitude Indicator
Serials w/o MD302 Standby Attitude Module: The attitude indicator is an electrically driven gyro that
displays a pictorial horizon and provides the pilot with a visual indication of the airplane’s pitch and roll
attitude by sensing pitching and rolling movements about the airplane’s lateral and longitudinal axis.
The attitude indicator is mounted on the LH bolster panel. 28 VDC for attitude gyro operation is sup-
plied through the 5-amp STDBY ATTD A circuit breaker on Essential Bus 1 and the 5-amp STDBY
ATTD B circuit breaker on Main Bus 1.
Serials w/ MD302 Standby Attitude Module: The optional MD302 Standby Attitude Module is a com-
bined standby airspeed indicator, standby altimeter, and standby attitude indicator located in the LH
bolster panel. The unit uses electronic sensors to provide attitude information. The attitude indicator
displays a pictorial horizon and provides the pilot with a visual indication of the airplane’s pitch and roll
attitude by sensing pitching and rolling movements about the airplane’s lateral and longitudinal axis. 28
VDC for MD302 Standby Attitude Module operation is supplied through the 5-amp STDBY ATTD A cir-
cuit breaker on Essential Bus 1 and the 5-amp STDBY ATTD B circuit breaker on Main Bus 1.
For additional maintenance practices on the MD302 Standby Attitude Module, see Flight Environmen-
tal Systems. (Refer to 34-10)
C. Magnetometer
A GMU 44 magnetometer, mounted outboard in the wing, provides three axis magnetic field vector
measurements and interfaces with the GSU 75 ADAHRS. A second magnetometer, located adjacent
to the first, may be installed by option. 28 VDC for the standard magnetometer is supplied through the
5-amp PFD A circuit breaker on Essential Bus 1. 28 VDC for the optional magnetometer is supplied
through the 5-amp PFD B circuit breaker on Main Bus 2.
The GMU 44 magnetometer is integral to the Perspective
+
Integrated Avionics system. For an over-
view of the Perspective
+
Avionics system, refer to Chapter 42, Integrated Modular Avionics. (Refer to
42-00)
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EFFECTIVITY:
CIRRUS AIRPLANE MAINTENANCE MANUAL MODEL SR20
1 Feb 2017
2. TROUBLESHOOTING
Trouble - Magnetic Compass Probable Cause Remedy
Excessive card error. Compass not properly compen-
sated.
Compensate instrument.
External magnetic interference. Locate magnetic interference and
eliminate if possible.
Excessive card oscillation. Insufficient fluid. Replace instrument.
Card sluggish. Weak card magnet. Replace instrument.
Excessive pivot friction or broken
jewel.
Replace instrument.
Liquid leakage. Loose bezel screws. Replace instrument.
Broken cover glass. Replace instrument.
Defective sealing gaskets. Replace instrument.
Defective light. Burned out lamp or broken circuit. Check lamp or continuity of wiring.
Card sticks. Altitude compensating diaphragm
collapsed.
Replace instrument.
Card does not move when com-
pensating screws are turned.
Gears that turn compensating
magnets stripped.
Replace instrument.
Compass swings erratically when
radio transmitter is keyed.
Normal. -
Excessive drift in either direction. Excessive vibration. Tighten mounting screws.
Trouble - Attitude Indicator Probable Cause Remedy
Horizon bar does not settle. Defective instrument. Replace instrument.
Excessive vibration. Tighten mounting screws.
Horizon bar oscillates or vibrates
excessively.
Excessive vibration. Tighten mounting screws.
CIRRUS AIRPLANE MAINTENANCE MANUAL MODEL SR20
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EFFECTIVITY:
Trouble Probable Cause Remedy
HDG FAIL annunciation. Interference from nearby metal
objects.
Ensure metal objects (tool boxes,
power carts, etc.) are not interfer-
ing with the magnetometer and
aircraft is not in hangar, near other
buildings, parked over metal drain-
age culverts or on hard surfaces
that may contain steel reinforce-
ments. Cycle power after moving
aircraft away from metal objects to
determine if metal objects were
the source of the interference.
Allow up to five minutes for the
heading to reinitialize.
Interference from cell phone. Ensure that a cell phone or a
device using cell phone technol-
ogy is not turned on (even in a
monitoring state) in the cabin.
Aircraft not stationary. Ensure the aircraft is stationary if
GPS is not available. Aircraft
movement (rocking the wings or
moving the tail) may cause the
heading to fail if it believes the air-
craft is in motion without GPS
input.
Interference from onboard electri-
cal components.
Perform a Magnetometer Interfer-
ence Test to check for interference
from onboard electrical system
components (e.g. NAV lights). Pay
particular attention to any new
electrical devices that have been
installed since the aircraft was
new. Correct any discrepancies
that do not allow this test to pass
before continuing.
Faulty connection between GSU
75 and GMU 44.
Check the wiring and any inline
connectors between the GSU and
GMU for faults.
GMU 44 requires calibration. Perform Adjustment/Test - GMU
44 Magnetometer Calibration.
(Refer to 34-20)
Faulty GMU 44. Replace GMU 44. (Refer to 34-20)
Faulty GSU 75. Replace GSU 75. (Refer to 34-10)
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EFFECTIVITY:
CIRRUS AIRPLANE MAINTENANCE MANUAL MODEL SR20
1 Feb 2017
ATTITUDE FAIL annunciation. Interference from cell phone. Ensure that a cell phone or a
device using cell phone technol-
ogy is not turned on (even in a
monitoring state) in the cabin.
Software or configuration error. Check PFD Alert Window for PFD,
MFD or GRS configuration, soft-
ware, or failed data path error
messages. Correct any errors
before proceeding.
Aircraft not stationary. Ensure the aircraft is stationary if
GPS is not available. Aircraft
movement (rocking the wings or
moving the tail) may cause the
heading to fail if it believes the air-
craft is in motion without GPS
input.
Check if GPS has acquired at
least four satellites, has a 3D navi-
gation solution, and a DOP of less
than 5.0.
Interference from nearby metal
objects.
Check for metal objects (tool
boxes, power carts, nearby large
steel structures, etc.) around air-
craft that could be interfering with
magnetometer.
Faulty connector or wiring. Check GSU 75 connector for
security and that proper wire har-
ness strain relief is provided.
GSU 75 not secured properly. Verify GSU 75 is secured tightly to
mounting rack and that mounting
rack is not loose. (CAUTION - do
not loosen mounting rack hard-
ware to airframe shelf or aircraft
will need to be re-leveled and the
PITCH/ROLL OFFSET procedure
performed).
Perform Engine Run-Up Test to
check if engine vibration is caus-
ing GSU 75 to go offline.
Faulty GSU 75. Replace GSU 75. (Refer to 34-10)
Faulty configuration module. Replace configuration module.
Trouble Probable Cause Remedy
CIRRUS AIRPLANE MAINTENANCE MANUAL MODEL SR20
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EFFECTIVITY:
3. MAINTENANCE PRACTICES
A. Magnetic Compass
(See Figure 34-201)
Note: When performing Operational Test - Magnetic Compass Calibration, use a non-mag-
netic or plastic screwdriver.
(1) Removal - Magnetic Compass
(a) Set BAT 1, BAT 2, and AVIONICS switches to OFF positions.
(b) Pull CABIN LIGHTS/OXYGEN circuit breaker.
(c) While supporting compass, loosen forward headliner. (Refer to 25-10)
(d) While supporting compass assembly, remove screws, washers, and nuts securing com-
pass to forward headliner.
(e) Disconnect electrical connector, then remove compass assembly from airplane.
(2) Installation - Magnetic Compass
(a) Connect electrical connector.
(b) Install screws, washers, and nuts securing compass to forward headliner.
(c) While supporting compass, install forward headliner. (Refer to 25-10)
(d) Reset CABIN LIGHTS/OXYGEN circuit breaker.
(e) Perform Operational Test - Magnetic Compass Calibration. (Refer to 34-20)
(3) Removal - Magnetic Compass Bracket
(a) Remove screw and washer securing compass bracket to cabin ceiling, then remove com-
pass bracket from airplane.
(4) Installation - Magnetic Compass Bracket
(a) Position compass bracket over mounting hole in forward headliner.
(b) Install screw and washer securing compass bracket to cabin ceiling.
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EFFECTIVITY:
CIRRUS AIRPLANE MAINTENANCE MANUAL MODEL SR20
(5) Operational Test - Magnetic Compass Calibration
(a) Place the airplane in as realistic flight environment as possible.
(b) Verify that doors are closed, flaps are in retracted position, engine is running, and airplane
is in level flight attitude.
(c) Set BAT 1, BAT 2, ALT 1, ALT 2, PITOT HEAT, and all radio switches to ON positions.
(d) Set all other cockpit controlled electrical switches should be in OFF positions.
Note: When performing Operational Test - Magnetic Compass Calibration, use
plastic adjustment tool included with new compass.
(e) Adjust compass for zero magnetic corrections. The level of magnetic correction is indi-
cated on top of the compass. Zero correction is indicated when spindle markings align
with markings on top of compass to form a line.
(f) Taxi airplane to compass rose.
(g) Align centerline of airplane on magnetic North heading. Adjust N-S set screw until com-
pass reads North.
(h) Align centerline of airplane on magnetic East heading. Adjust E-W set screw until com-
pass reads East.
(i) Align centerline of airplane on magnetic South heading, then note resulting South error.
Adjust N-S set screw until one-half of error is removed.
(j) Align centerline of airplane on magnetic West heading, then note resulting West error.
Adjust E-W set screw until one-half of error is removed.
(k) Align centerline of airplane in successive magnetic 30-degree headings and record com-
pass readings on appropriate deviation card. Deviations must not exceed 10 degrees on
any heading.
(l) Set BAT 1, BAT 2, ALT 1, ALT 2, PITOT HEAT, and all radio switches to OFF positions.
1 Feb 2017
CIRRUS AIRPLANE MAINTENANCE MANUAL MODEL SR20
34-20
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EFFECTIVITY:
Figure 34-201
Magnetic Compass Installation
E-W
ADJUSTMENT HOLE
(REF)
N-S
ADJUSTMENT HOLE
(REF)
A
DETAIL
FORWARD
HEADLINER
(REF)
SR20_MM34_5102
2
4
7
5
6
LEGEND
1. Bracket
2. Screw
3
. Calibration Card
4
. Compass
5
. Nut
6
. Connector
7
. Washer
1
3
7
2
1 Feb 2017
34-20
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Serials w/o MD302 Standby Attitude Module
EFFECTIVITY:
CIRRUS AIRPLANE MAINTENANCE MANUAL MODEL SR20
B. Attitude Indicator - Serials w/o MD302 Standby Attitude Module
(See Figure 34-202)
(1) Removal - Attitude Indicator
(a) Set BAT 1, BAT 2, and AVIONICS switches to OFF positions.
(b) Pull STDBY ATTD A, STDBY ATTD B, and CABIN LIGHTS/OXYGEN circuit breakers.
(c) Remove LH kick plate. (Refer to 25-10)
(d) Disconnect electrical connector.
(e) While supporting attitude indicator, remove screws and washers securing unit to bolster
panel.
(f) Cap off fittings on back of attitude indicator to prevent possible contamination and remove
attitude indicator from airplane.
(2) Installation - Attitude Indicator
(a) Position attitude indicator in bolster panel and secure with screws and washers.
(b) Connect electrical connector.
(c) Reset STDBY ATTD A, STDBY ATTD B, and CABIN LIGHTS/OXYGEN circuit breakers.
(d) Perform Operational Test - Attitude Indicator. (Refer to 34-20)
(e) Install LH kick plate. (Refer to 25-10)
(3) Operational Test - Attitude Indicator
(a) Set BAT 1 switch to ON position.
(b) Verify gyro flag is out of view.
(c) As gyro speeds up, the attitude indicator will stabilize.
(d) After 2 to 3 minutes, pull PULL TO CAGE knob on attitude indicator.
(e) Verify attitude indicator is stabilized with artificial horizon resting horizontally and slip indi-
cator ball is centered.
(f) Set BAT 1 switch to OFF position.
1 Feb 2017
CIRRUS AIRPLANE MAINTENANCE MANUAL MODEL SR20
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Serials w/o MD302 Standby Attitude Module
EFFECTIVITY:
1 Feb 2017
Figure 34-202
Attitude Indicator Installation - Serials w/o MD302 Standby Attitude Module
Serials w/o MD302 Standby Attitude Module.
A
DETAIL
A
3
1
4
2
LEGEND
1. Screw
2. Washer
3. Attitude Indicator
4. Knob
SR20_MM34_5106
BOLSTER PANEL
(REF)
34-20
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EFFECTIVITY:
CIRRUS AIRPLANE MAINTENANCE MANUAL MODEL SR20
C. GMU 44 Magnetometer
(See Figure 34-203)
CAUTION: When performing maintenance practices on the magnetometer, use a non-magnetic
screwdriver. Use brass screws and washers to secure the magnetometer.
(1) Removal - GMU 44 Magnetometer
(a) Set BAT 1, BAT 2, and AVIONICS switches to OFF positions.
(b) Remove wing access panel RW12. (Refer to 06-00)
(c) Remove cable tie securing magnetometer connectors to wing.
(d) Disconnect magnetometers from wire harness.
(e) Remove screws securing magnetometer mounting plate to wing.
(f) Remove screws, washers, and nuts securing magnetometer to mounting plate. Remove
magnetometer from airplane.
(2) Installation - GMU 44 Magnetometer
(a) Position magnetometer to mounting plate so that arrow will point forward when installed in
wing. Secure with screws, washers, and nuts.
Note: Ensure arrow on magnetometer is pointing forward in airplane and non-
magnetic hardware is used to secure magnetometer to mounting plate.
(b) Position magnetometer mounting plate to wing and secure with screws.
(c) Connect magnetometers to wire harness.
(d) Install cable tie securing magnetometer connectors to wing.
(e) Install wing access panel RW12. (Refer to 06-00)
(f) If GMU 44 has been replaced with a new or different unit, or original unit has been
repaired, perform Adjustment/Test - Component Software and Configuration Loading.
(Refer to 42-00)
(g) Perform Adjustment/Test - GMU 44 Magnetometer Calibration. (Refer to 34-20)
(3) Adjustment/Test - GMU 44 Magnetometer Calibration
Note: Prior to calibrating magnetometer, verify that doors are closed, flaps are in
retracted position, engine is running, and airplane is in level flight attitude.
(a) Perform GMU 44 Magnetometer Calibration according to Cirrus Perspective
+
Line Mainte-
nance Manual.
1 Feb 2017
CIRRUS AIRPLANE MAINTENANCE MANUAL MODEL SR20
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EFFECTIVITY:
Figure 34-203
GMU 44 Magnetometer Installation
2
3
8
7
SR20_MM34_5108
LEGEND
1. Magnetometer
2. Screw
3. Washer
4. Nut
5. Tie Down
6. Strap, Tie Down
7. Standoff
8. Mounting Plate
1
5
6
4
3
1
2
UPPER WING
SKIN (REF)
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CIRRUS AIRPLANE MAINTENANCE MANUAL MODEL SR20
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Cirrus SR20 Maintenance Manual

Type
Maintenance Manual

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