Piper CHEROKEE WARRIOR PA-28-151 1995 Maintenance Manual page 355

PIPER CHEROKEE WARRIOR SERVICE MANUAL
10-54 ELECTRIC INSTRUMENTS
10-55 TURN INDICATOR
10-56. GENERAL
PA-28-151, Warrior airplanes are equipped with a turn and slip (turn and bank) indicator. PA-28-161,
Warrior II and Warrior III airplanes are equipped with a turn c o o r d i n a t o r. The conventional turn and slip
i n d i c ator(s) are available as an option on both models. The gyro in either type is electrically operated. The
turn portion of both indicators is a g y r oscope, while a ball sealed in a curved glass tube filled with dampening
fluid is used to maintain coordinated flight. Both types work on the precession principle.
The gyro in the turn coordinator is installed so that the indicator, mechanically linked to the gyro,
responds to both the rate of yaw or turn, and rate (not degree) of roll. With this indicator, if the aircraft is rolled
right and left rapidly, the indicator will move while the airplane is r o l l i n g , indicating the rate (degrees per
second) of roll. If the aircraft is then held in at a constant bank angle, and rudder is applied to maintain headi n g
(such as when "slipping"), the indicator will come back to zero rate, indicating no roll or turn. Should the
a i rplane be permitted to turn once a desired bank angle is established, the indicator will remain deflected in
the direction of the roll/turn, now indicating rate of turn. Thus, using the flight controls to keep the indicator
on the appropriate turn index, will result in the airplane becoming established in a coordinated, standard rate
(3° per second) turn.
The gyro in the turn and slip indicator, which is the older style, is installed so that the needle responds
only to rate of yaw or rate turn. It has a vertical needle in the center of the dial mechanically linked to the
gyro. Unless the aircraft is turning or yawing, the needle will not move regardless of roll r a t e. The greater
the r a t e of turn (degree of heading change per second), the more the gyro is precessed, resulting in
greater needle deflection in the direction of turn.
10-57. TROUBLESHOOTING
TABLE X-XV. TROUBLESHOOTING TURN INDICATORS
Trouble
Pointer fails to respond.
Incorrect sensitivity.
Incorrect turn rate
Ball sticky.
Ball not in center when
aircraft is correctly trimmed.
Instrument will not indicate a
turn.
10-57. REMOVAL AND REPLACEMENT. Refer to paragraph 10-71
Revised: February 28, 1995
Cause
Foreign matter lodged in
instrument.
Out of calibration.
Out of calibration.
Aircraft not in coordinated
turn. (Turn and slip indictor)
Flat spot on ball.
Instrument not level in panel.
No power to instrument.
Instrument malfunction.
2C19
Island Enterprises
Remedy
Replace instrument.
Replace instrument.
Replace instrument.
Center ball in turn.
Replace instrument.
Level instrument.
Check circuit and repair.
Replace instrument.
INSTRUMENTS