Installation Of Rudder Trim Sender Assembly; Rigging And Adjustment Of Rudder Trim; Rigging And Adjustment Of Rudder Trim Sender And Indicator - Piper Navajo PA-31 Service Manual

PIPER NAVAJO SERVICE MANUAL
5-52. INSTALLATION OF RUDDER TRIM SENDER ASSEMBLY. (Refer to Figure 5-10.)
a. Install the sender unit (26) on its mounting bracket by placing the index tab on the sender into
the index slot in the bracket. Secure the sender.
b.
Position the sender arm (28) on the shaft (27) of the sender and allow the arm to rotate freely
until adjustment is made.
c. Position the sender mounting bracket in fin, install attachment screws and secure.
d. Attach the sender arm (28) on the trim screw (30).
e. Connect the electrical leads.
f.
Rig sender unit per Paragraph 5-54.
g.
Install access plate.
5-53. RIGGING AND ADJUSTMENT OF RUDDER TRIM. (Refer to Figure 5-10.)
a. To adjust the rudder trim, it must be ascertained that the following has been accomplished either
during installation or as a preadjustment check:
1. Trim cables are evenly wrapped (centered) on their drums, both in the control pedestal and
in the fin, and both cable turnbuckles are located approximately at fuselage station 287.5.
2. The trim drum (32) in the fin is centered between the stops (29 and 40) of the trim screw
(30).
3.
Cable tension is set as given in Table V-I.
b.
Remove the access plate on the right side of the vertical fin.
c. With the trim screw connected to the control rod and not allowed to rotate, turn the trim drum
until 1.21 of an inch exists between the forward screw stop and the drum housing, as measured along the
screw. (Neutral position of the screw is at this measurement.)
d. With the trim screw in neutral position, the trailing edges of the tab and rudder should align.
Should they not, remove the attachment bolt (37) and loosen the jam nut (35) on the rod end (36) at the
aft end of the tab control rod. Turn the rod end until the trailing edges align. Secure attachment bolt (37)
and rod end jam nut (35).
e. Turn the trim in each direction to screw stops to check tab angle or measured distance from the
centerline of the rudder as given in Table V-I and also check minimum number of wraps left on trim drum.
(Minimum allowable is one and one quarter turns.)
f. Check rigging and adjustment of trim sender and indicator per Paragraph 5-54.
5-54. RIGGING AND ADJUSTMENT OF RUDDER TRIM SENDER AND INDICATOR. (Refer to Figure
5-13.)
a. Remove the access plate on the right side of the vertical fin.
b. Ascertain that the rudder trim is properly adjusted per Paragraph 5-53.
c. With the arm (28) on the sender shaft free to rotate, set the rudder and rudder tab in neutral
position.
d.
Calibrate the trim indicator located in the control pedestal by first rotating the sender shaft (27),
as viewed from the shaft end, in a clockwise direction to its stop position.
e.
Turn on the master switch. A minimum of 24 volts must be supplied to the electrical system
when making this adjustment.
f. Rotate the sender shaft slowly counter-clockwise when viewed from the shaft end, until the trim
indicator on the pedestal reads neutral. Tighten the arm (28) on the sender shaft (27).
g. Turn trim to both extremes and observe trim reading. Indicator pointer should travel to both
extreme positions on the indicator dial.
h.
Should the indicator pointer not reach either extreme position on the dial, return the tab to
neutral, loosen the sender in its bracket and slide it closer to the trim screw. Tighten the sender and check
neutral indication. If neutral indication has changed, repeat Steps f and g.
i. Install the access plate.
Reissued: 10/12/79
SURFACE CONTROLS
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