Piper Navajo PA-31 Service Manual page 221

PIPER NAVAJO SERVICE MANUAL
d. Check that there is .30 of an inch between the forward screw stop (33) and the drum housing
(30) as measured along the screw. If this measurement is not correct, disconnect the fork of the trim screw
(32) from the trim control rod (20), if not previously disconnected, and turn the trim screw until .30 of an
inch is obtained. Hold the trim drum neutral while turning the screw. (The trim screw neutral position is at
this measurement.) Reconnect with screw stop nuts down.
e.
With the trim screw, trim drum and elevator in neutral position, the trailing edges of the tab and
elevator should align. Should they not, loosen the jam nuts (40) on each end of the control rod (20) and
rotate the rod until the trailing edges align. Tighten jam nuts (40).
f.
Turn the trim in each direction to screw stops to check tab angle as given in Table V-I and also
check minimum number of wraps left on the drum. (Minimum allowable is one and one-quarter turns.)
g. Check rigging and adjustment of trim sender and indicator per Paragraph 5-36.
5-35a. RIGGING AND ADJUSTMENT OF ELEVATOR TRIM PA-31-325 ONLY).
PP
(Refer to Figure 5-5 )
a. To adjust the elevator trim, it must be ascertained that the following has been accomplished
either during installation or as a preadjustment check:
1. Remove access plate on underside of the right horizontal stabilizer.
2. Cable tension is set as given in Table V-I.
3. With the trim control set for full nose up trim, there are six full cable wraps from the
forward end (31) of the cable drum and the actuator screw is against the rear stop (41).
b.
If conditions of item three above are not met, proceed as follows:
1. Rotate the trim control wheel for nose up trim, stopping six full cable wraps from the
forward end (31) of the cable drum.
2. Disconnect the fork of the trim screw (32) from the trim control rod (20) which will allow
the screw to turn.
3. Rotate the trim drum to the correct number of cable wraps and then turn the screw against
the rear stop.
4.
Reassemble and secure the trim screw fork to the control rod with the screw stop nuts
down.
c.
With the elevator in neutral and the trim wheel in the full nose up position, adjust the control rod
ends (39) to set the trim tab at 40
°
+ 10 trailing edge down. Check for proper rod end engagement and
secure the rod.
b.
Turn the trim control wheel in each direction from stop to stop to check operation. Recheck tab
angles as given in Table V-I, also check for minimum number of cable wraps on drum at each end.
(Minimum allowable is 2 wraps.)
Revised: 3/2/84
SURFACE CONTROLS
1J5