Piper Arrow IV Turbo Maintenance Manual page 438

Trouble
Altimeter changes reading
as aircraft is banked.
Altimeter requires re-
setting frequently.
When any connections in the static system are opened for
checking, system must be rechecked per F.A.R. 23.1325.
AIRSPEED INDICATOR.
The airspeed indicator provides a means of indicating the speed of the airplane passing through the air. The
airspeed indication is the differential pressure reading between pitot air to 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 also has the necessary operating range markings for safe operation of the airplane.
CHART 3403. TROUBLESHOOTING (AIRSPEED TUBES AND INDICATOR)
Trouble
Pointers of static instru-
ments do not indicate
properly.
Pointer of instrument
oscillates.
Instrument reads high.
PIPER AIRCRAFT
PA-28RT-201 / 201T
MAINTENANCE MANUAL
CHART 3402. TROUBLESHOOTING (ALTIMETER) (cont)
Water in static line.
Temperature compensator
inoperative.
—NOTE—
Leak in instrument case or
in pitot lines.
Defective mechanism.
Pointer not on zero.
Leaking static system.
Cause
Cause
2G15
Remedy
Remove static lines from all
instruments, and blow line
clear from cockpit to pitot
head.
Change instrument.
Remedy
Check for leak and seal.
Replace instrument.
Replace instrument.
Find leak and correct.
34-10-03
Page 34-07
December 1, 1978