Cessna 150M - Trouble Shooting-Altimeter; Trouble Shooting-Vertical Speed Indicator.

15-20. TROUBLE SHOOTING--ALTIMETER
TROUBLE
PROBABLE CAUSE
REMEDY
INSTRUMENT FAILS
TO Static line plugged.
Check line for obstructions.
OPERATE.
Blowout lines.
Defective mechanism.
Substitute known-good alti-
meter and check reading.
Replace instrument.
INCORRECT INDICATION.
Hands not carefully set.
Re set hands with knob.
Leaking diaphragm.
Substitute known-good alti-
meter and check reading.
Replace instrument.
Pointers out of calibration.
Compare reading with known-
good
altimeter. Replace
instrument.
HAND OSCILLATES.
Static pressure irregular.
Check lines for obstruction
or leaks.
Blowout lines,
tighten connections.
Leak in airspeed or vertical
Check other instruments and
speed indicator installations.
system plumbing for leaks.
Blowout lines, tighten con-
nections.
15-21. TROUBLE SHOOTING--VERTICAL SPEED INDICATOR.
TROUBLE
PROBABLE CAUSE
REMEDY
INSTRUMENT FAILS
TO
Static line plugged.
Check line for obstructions.
OPERATE.
Blowout lines.
Static line broken.
Check line for damage, con-
nections for security. Re-
pair or replace damaged line,
tighten connections.
INCORRECT INDICATION. Partially plugged static line.
Check line for obstructions.
Blowout lines.
Ruptured diaphragm.
Substitute known-good indicator
and check reading. Replace
instrument.
Pointer off zero.
Reset pointer to zero. Reset
pointer to zero.
POINTER OSCILLATES.
Partially plugged static line.
Check line for obstructions.
Blowout lines.
15-8