____________________________________________________________________
Cirrus Perspective™ Line Maintenance Manual
Page 5-71
190-00920-00
Rev.
E
5.9
GRS
77/GMU
44
RELATED
ALERTS
AND
PROBLEMS
5.9.1
Common
Problems
Symptom
Recommended
Action
AHRS
does
not
complete
initialization
•
Make
sure
a
cell
phone
or
a
device
using
cell
phone
technology
is
not
turned
on
(even
in
a
monitoring
state)
in
the
cabin.
•
Make
sure
the
GPS
has
acquired
at
least
four
satellites,
has
a
3D
navigation
solution,
and
a
DOP
of
less
than
5.0.
This
is
particularly
important
if
this
issue
appears
during
ground
operation
only.
•
Calibrate
the
GRS
77.
•
Check
GRS
77
configuration
module
wiring
for
damage.
•
Check
GRS
77
connector
for
bent
pins.
−
If
no
damage
can
be
found,
replace
GRS
77
configuration
module.
•
If
problem
persists,
replace
the
GRS
77.
Attitude
appears
unstable
•
Make
sure
a
cell
phone
or
a
device
using
cell
phone
technology
is
not
turned
on
(even
in
a
monitoring
state)
in
the
cabin.
•
Make
sure
the
four
GRS
77
mounting
screws
are
tight.
Finger
tight
is
not
sufficient,
a
screwdriver
must
be
used
to
verify.
•
Make
sure
the
mounting
rack
and
airframe
shelf
are
secure
and
all
hardware
and
brackets
are
present
(CAUTION
‐
do
not
loosen
the
mounting
rack
hardware
to
the
airframe
shelf
or
the
aircraft
will
need
to
be
re
‐
leveled
and
the
PITCH/ROLL
OFFSET
procedure
performed).
•
Make
sure
the
GRS
77
connector
is
securely
fastened
and
proper
strain
relief
is
provided.
•
Remove
GRS
77
connector
and
make
sure
there
are
no
bent
pins.
•
Replace
the
GRS
77.
•
Contact
Garmin
for
further
troubleshooting
if
required.
Summary of Contents for Cirrus Perspective SR20
Page 2: ......
