Balancing Equipment; Balancing Definitions; Aileron Balancing Procedure - Piper Navajo Chieftain PA-31-350 Service Manual

NAVAJO CHIEFTAIN SERVICE MANUAL
This balancing information will cover the various control surface assemblies used throughout the
production life span of the PA-31-350 airplane. Particular attention should be given to assembly numbers
being balanced; this will insure that the correct procedures and tolerances as referred to in the text and
Table IV-I are correct for the assembly being serviced.
4-92. BALANCING EQUIPMENT. Balancing must be done using the test weights (if required)called forin
the text and Table IV-I for each surface. Any control surface being balanced must be removed from the aircraft
and placed in a test fixture (jig) as shown in Figures 4-16, 4-17, and 4-19. The balancing must be accomplished
in a draft free area and in a manner which allows unrestricted movement of the control surface.
4-93. BALANCING DEFINITIONS. The following is a list of balancing definitions as used in this service
manual:
a.
Master Test Weight: A fabricated tool temporarily attached to the control surface to determine
when the surface is at its lower static balance limits.
b. Balance Weight: Weight attached permanently to a control surface to produce a static hinge
moment within the required range (such as 30 inch-pounds
+
10 inch-pounds trailing edge heavy).
c. Trailing Edge Heavy: Positive static hinge moment; trailing edge of the surface moves downward
when released from a neutral position.
d. Leading Edge Heavy: Negative static hinge moment; leading edge of the surface moves
downward when released from a neutral position.
e.
Master Test Weight Arm: Perpendicular distance between the control surface hinge line and the
point of application of the master test weight.
f. 0.1 Pound Test Weight: Small weight added to the master test weight during balancing procedure
when the surface is trailing edge heavy with the basic master test weight installed.
g. Trim Weight: Small weight or weights added to the surface balance weight to bring the surface
within tolerances. (Sometimes required depending on variations in surface construction.)
4-94. AILERON BALANCING PROCEDURE. (Refer to Figure 4-16.)
PPS-50022-1
a. Remove the aileron from the airplane. (Refer to Paragraphs 4-16, 4-91 and 4-92.)
b. Place the aileron on a balancing jig as illustrated in Figure 4-16. Establish a horizontal reference mark
which aligns with the trailing edge of the aileron when it is held in a horizontal level position (chord line level).
c.
Ascertain that the surface rotates freely with no binding at the knife edges.
d.
Assemblies P/N 40200-22, 40200-23 and 40200-41:
i. The specified master test weight should be hung from the front balance weight attachment bolt.
(Refer to Figure 4-16. Master Test Weight Arm "A.")
2.
If the aileron balances with the master test weight installed, it is at the minimum static
balance limit and is satisfactory.
3. If the aileron is leading edge heavy with the master test weight installed, material must be
removed from the surface balance weight until a balanced condition is obtained. This would also result in
the lower static balance limit.
4. If the aileron is trailing edge heavy with the master test weight installed, it must be
determined that the aileron does not exceed the upper static limits from Table IV-I.
5. Add individual 0.1 lb. test weights to the master test weight until the aileron balances.
6. If the number of 0.1 lb. test weights does not exceed the maximum allowable from Table
IV-I, the aileron is within the static limits and is satisfactory.
7. If the number of 0. Ib. test weights added to the master test weight to balance the aileron
exceeds the maximum allowable from Table IV-I, the aileron balance exceeds static limits.
8. The reason for the excessive unbalance must be determined; the unbalance must be
corrected and the aileron rechecked.
e. Assemblies P/N 40200-42 and 40200-43.
Reissued: 9/23/80
1G12
STRUCTURES