Mooney M20M - Altimeter-Trouble Shooting; Directional Gyro-Trouble Shooting

MOONEY
AIRCRAFT
CORPORATION
M20M
SERVICE
AND
MAINTENANCE
MANUAL
34-13-01
ALTIMETER
TROUBLE
SHOOTING
TROUBLE
PROBABLE
CAUSE
REMEDY
Excess scale
error.
Improper
calibration
adjustment.
Replace
instrument.
Excessive
pointer
oscillation.
Defective
mechanism.
Replace
instrument.
High
reading.
Static
pressure
system
leak. Eliminate
leak
in static
pressure
system.
Setting
knob is hard
to turn.
Wrong
lubricant
or
lack of
Replace
instrument.
lubrication.
Inner reference
marker
fails
to
Marker
out
of
engagement.
Replace
instrument.
move
when
setting
knob is
rotated.
Setting
is
loose
or
Excessive
vibration.
Tighten
instrument
screw
if
loose.
missing.
Replace
instrument
if
screw
is
missing.
Cracked
or
loose
cover
glass.
Excessive
vibration.
Replace
instrument.
Dull
or
discolored luminous
Age.
Replace
instrument.
markings.
Barometric
scale and
reference
Shift
in
mechanism. Reset
pointers.
markers
are
out
of
synchronization
with
pointers.
Barometric scale and
reference
Slippage
of
mating
parts.
Replace
instrument.
markers
are
out
of
synchronization.
34-20-00
DIRECTIONAL GYRO
COMPASS
satisfactory
operation
is
4.25
+/-.2
to 5.5
+0.0/-.2.
The
This
vacuum-operated
instrument
indicates
the
heading
vacuum
system
filters should be
changed
each
500
reference.
The directional
gym
rotor
is
air driven
and
hours
or
at
one
year
intervals,
whichever
occurs
first.
rotates
with
its
spin
axis
horizontal. The knob
is used
to
(See
Trouble
Shooting
Chart,
for
maintenance
reset
basic directional
heading.
Vacuum
pressure
for
i"structions.)
34-20-01
DIRECTIONAL GYRO
TROUBLE
SHOOTING
OIACUUM
ONLY)
TROUBLE
PROBABLE
CAUSE
REMEDY
Excessive
drift
in
either
Dirty
air
filter
thigh
vacuum
Inspect
filter.
Replace
if
necessary.
direction.
indication).
Excessive vibration.
Test with
vibrometer.
If
vibration
amplitude
is
more
than
.004
inch,
examine shock
mountings
to
see
if
connections
are
pulling
on
instrument.
Insufficient
vacuum.
If
vacuum
indication
is
below
Correct
for
insufficient
vacuum
as
4.25
IN.
Hg.,
check
as
follows:
follows:
1.
Vacuum
regulating
valve
1.
Adjust
vacuum
regulating
valve.
improperly
adjusted.
2.
Pump
failure.
2.
Repair
or
replace
pump.
3.
Vacuum
line
kinked,
leaking,
3.
Locate
and,
if
defective,
replace
or
or
too
long
for
its diameter.
repair
vacuum
line.
Check
for
collasped
inner
wall of flexible
hose.
4-99
34-13-01
OLDWILLWAYNE