Airspeed Indicator - Piper Navajo Chieftain PA-31-350 Service Manual

NAVAJO CHIEFTAIN SERVICE MANUAL
TABLE X-V. ALTIMETER (cont.)
Cause
Remedy
Trouble
Altimeter sticks at
altitude or does not
change with change
of altitude.
Altimeter changes
reading as aircraft
is banked.
Altimeter requires
resetting frequently.
Water or restriction
in static line.
Water in static line.
Temperature compensator
inoperative.
Remove static lines
from all instruments,
blow line clear from
cockpit to sensor.
Remove static lines
from all instruments,
and blow line clear
from cockpit to sensor.
Change instrument.
NOTE
When any connections in the static system are opened for check,
system must be rechecked per Part FAR 23.1325.
1040. REMOVAL AND REPLACEMENT. (Refer to paragraph 10-94
of this section.)
10-41. AIRSPEED INDICATOR.
10-42. GENERAL. The airspeed indicator provides a means of indicating the
speed of the airplane passing
through the air. The airspeed indication depends on the differential pressure
between pitot air pressure and
static air pressure. This instrument has the diaphragm vented to the pitot air
source and the case is vented
to the static air system. As the airplane increases speed, the pitot air
pressure increases, causing the
diaphragm to expand. A mechanical linkage picks up this motion and moves
the instrument pointer to the
indicated speed. The instrument dial is calibrated in knots and miles per hour,
and also has the necessary
operating range markings for safe operation of the airplane.
10-43. TROUBLESHOOTING.
TABLE X-VI. AIRSPEED TUBES AND INDICATOR
Trouble
Cause
Remedy
Pointers of static
instruments do not
indicate properly.
Pointer of instru-
ment oscillates.
Leak in instrument
case or in static
lines.
Defective mechanism.
Check for leak and seal.
Replace instrument.
INSTRUMENTS
Reissued: 9/23/80
3B13