—NOTE —
When any connections in the static system are opened for checking,
system must be rechecked per F.A.R. 23.1325.
10-42. REMOVAL AND REPLACEMENT. Refer to Paragraph 10-87 of this section.
10-43. SENSITIVE ALTIMETER.
10-44. 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 thousandths of feet and the short pointer in ten
thousandths 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. The altimeter consists of a sealed diaphragm that is
connected to the pointers through a mechanical linkage. 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.
10-45. TROUBLESHOOTING.
TABLE X-V. ALTIMETER
Trouble
Cause
Remedy
Excessive scale error.
Improper calibration
Replace instrument.
adjustment.
Excessive pointer
Defective mechanism.
Replace instrument.
oscillation.
Altimeter sticks at
Water or restriction In
Remove static lines
altitude or does not
static line.
from all instruments,
change with change of
blow line clear from
altitude.
cockpit to pitot head.
Altimeter changes
Water in static line.
Remove static lines.
reading as aircraft
from all instruments,
is banked.
and blow line clear from
cockpit to pitot head.
Altimeter requires
Temperature compensator
Change instrument.
resetting frequently.
inoperative.
High or low reading.
Improper venting.
Eliminate leak in static
pressure system and check
alignment of airspeed tube.
Setting knob is hard
Wrong lubrication or
Replace instrument.
to turn.
lack of lubrication
PIPER AIRCRAFT
PA-28-161 CADET
AIRPLANE MAINTENANCE MANUAL
Issued: FEBRUARY. 28, 1989
I N S T R U M E N T
2B24
