Piper Arrow IV Turbo Maintenance Manual page 443

TURN AND BANK INDICATOR.
The turn and bank indicator can be either vacuum driven or electric. The turn portion of the indicator is a
gyroscope, while the bank portion of the indicator is a ball sealed in a curved glass tube filled with damping
fluid. There are two styles of this unit. The first is the old style with a vertical needle in the center of the dial.
This instrument reads only the rate of turn, and unless the aircraft is turning, the needle will not move
regardless of bank angle. The other style is the turn coordinator which indicates both the rate of turn and rate
of roll. With this indicator, if the aircraft is rolled right and left rapidly, the indicator will move, indicating a
turn, but if the aircraft is held in a bank, and rudder is applied, the indicator will come back to zero indicating
no turn.
CHART 3407. TROUBLESHOOTING (TURN AND BANK INDICATOR)
Trouble
Pointer fails to respond.
Incorrect sensitivity.
Incorrect turn rate (vacuum
style).
Incorrect turn rate
(electric).
Ball sticky.
Ball not in center when air-
craft is correctly trimmed.
Instrument will not run
(electric).
PIPER AIRCRAFT
PA-28RT-201 / 201T
MAINTENANCE MANUAL
Cause
Foreign matter lodged in
instrument.
Out of calibration.
High or low vacuum.
Filter dirty.
Out of calibration.
Aircraft not in coordinated
turn.
Flat spot on ball.
Instrument not level in
panel.
No power to instrument.
Instrument malfunction.
—END—
2G20
Remedy
Replace instrument.
Replace instrument.
Check vacuum and adjust.
Replace filter.
Replace instrument.
Center ball in turn.
Replace instrument.
Level instrument.
Check circuit and repair.
Replace instrument.
34-10-08
Page 34-12
December 1, 1978