Piper CHEROKEE WARRIOR PA-28-151 1995 Maintenance Manual page 344

PIPER CHEROKEE WARRIOR SERVICE MANUAL
TABLE X-IV. TROUBLESHOOTING VERTICAL SPEED INDICATOR (cont.)
TROUBLE
Instrument reads excessively less
than actual rate during climb or
descent.
10-32. REMOVAL AND REPLACEMENT. Refer to Paragraph 10-71 of this section.
10-33. SENSITIVE ALTIMETER.
10-34. GENERAL.
The altimeter indicates pressure altitude in feet above sea level. The indicator has three pointers and a
dial scale. The long pointer is read in hundreds of feet, the middle pointer in thousands of feet and the short
pointer in ten thousands of feet. A barometric pressure window is located on the right side of the indicator dial
and is set by the knob located on the lower left corner of the instrument to compensate for variation from
s t a ndard sea level pressure. The altimeter is a sealed diaphragm connected to the pointers through a mechanic a l
linkage. The diaphragm mounting is made of bi-metallic temperature sensitive strips that compensates for
variation from standard temperatures.The instrument case is vented to the static air system and, as static air
pressure decreases, the diaphragm expands, causing the pointers to move through the mechanical linkage.
10-35. TROUBLESHOOTING.
If any connections in static system are opened for mainten a n c e ,
the complete system must be rechecked per F.A.R. 23.1325.
TROUBLE
Excessive scale error.
Excessive pointer oscillation.
Altimeter sticks at or does not
change with change of altitude.
Altimeter changes reading as
a i rcraft is banked.
Altimeter requires frequent
r e s e t t i n g
High or low reading.
Revised: February 28, 1995
CAUSE
Instrument case broken or
l e a king.
NOTE
TABLE X-V. TROUBLESHOOTING ALTIMETER
CAUSE
Improper calibration adjustment.
Defective mechanism.
Water or restriction in altitude
static line.
Water in static line.
T e m p e r a t u r e c o m p e n s a t o r
i n o p e r a tive.
Improper venting.
2C8
Island Enterprises
REMEDY
Replace instrument.
REMEDY
Replace instrument.
Replace instrument.
Remove static lines from all
instruments. Blow line clear
from cockpit to pitot head.
Remove static lines.from all
instruments. Blow line clear fro
cockpit to pitot head.
Change instrument.
Eliminate leak or restrictions in
static pressure system. Check
alignment of pitot/static mast.
INSTRUMENTS