TABLE X-V. ALTIMETER (cont.)
Trouble
Cause
Remedy
Inner reference marker
Out of engagement.
Replace instrument.
fails to move when
setting knob is rotated.
Setting knob set screw
Not tight when
Tighten instrument
loose or missing.
altimeter was reset
screw, if loose.
Replace instrument,
if screw is missing.
Cracked or loose
Case gasket hardened.
Replace instrument.
cover glass.
Dull or discolored
Age.
Replace instrument.
markings.
Barometric scale and
Slippage of mating
Replace instrument.
reference markers out
parts.
of synchronism.
Barometric scale and
Drift in mechanism.
Reset pointers. refer to the
reference markers out
latest revision of AC 43 13-1
of synchronism with
Pointers.
—NOTE—
When any connections in the static system are opened for checking.
system must be rechecked per F.A.R. 23.1325.
10-46. REMOVAL AND REPLACEMENT. Refer to Paragraph 10-87 of this section.
10-47. AIRSPEED INDICATOR.
10-48. GENERAL. 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 a 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.
PIPER AIRCRAFT
PA-28-161 CADET
AIRPLANE MAINTENANCE MANUAL
Issued: FEBRUARY. 28, 1989
I N S T R U M E N T
2C1
