500 
27-09-400  May 01/01 
Page 106 
BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details. 

FLIGHT CONTROLS TRIM CORRECTION - ADJUSTMENT/TEST
1. Purpose and Scope
A.  The purpose of this procedure is to describe proper methods to correct airplane configuration when flight controls trim discrepancies are excessive.
B.  The major headings are as follows:
(1)  
Purpose and Scope

(2)  
Adjust Trailing Edge Flaps for FLAP UP Discrepancy

(3)  
Adjust Trailing Edge Flaps for 15-Unit Discrepancy

(4)  
Adjust Trailing Edge Flaps for FLAP UP and 15-Unit Discrepancy

(5)  
Adjust Trailing Edge Flaps for 40-Unit Discrepancy

(6)  
Aileron Tab Adjustment to Equalize Lateral Manual Reversion Forces

(7)  
Speed Brake Rolloff Discrepancy Correction.

(8)  
Rudder Trim Discrepancy Correction. (Perform rudder travel test (Ref 27-21-00 A/T).

(9)  
Rudder Standby Power Discrepancy Correction

(10)
Elevator Power Off Discrepancy Correction

(11)
Leading Edge Slat Trailing Edge Gap Mismatch

(12)
Flight Controls Surface Mismatch Record

C.  All lateral trim corrections shall be made from control wheel positions reported by pilot, not the aileron trim indicator reading. (One aileron trim unit equals 6 degrees at the control wheel.)
D.  For best results care should be taken to optimize symmetry between left and right wings within given tolerances.
E.  A graphic aid to trim correction is provided (Fig. 507). It is expected that use of this aid will facilitate the process of selecting trim correction adjustments and improve skills in making the proper choice if these steps are followed:
(1)  
Plot lateral and record rudder trim.

(2)  
Record adjustments to be made.

(3)  
Plot and record expected results.

(4)  
Plot, record and compare actual results with expected results.

F.  Following any shimming for the purpose of trim correction, the allowable tolerance of
 0.00 to - 0.25 inch for outboard flap trailing edge and +0.25 inch for inboard flap trailing edge mismatch with the wing chord plane may be exceeded.
501 
Jun 20/91  BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details.  27-09-400 Page 501 

2.  Adjust Trailing Edge Flaps for FLAP UP Discrepancy
A.  General
(1)  The following procedures provide instructions for adjusting the trailing edge flaps to maintain straight and level flight without excessive aileron trim when all lateral control surfaces, flaps, and rudder are rigged within allowable tolerances. The adjustment is made by raising or lowering the outboard flaps by shimming between the flap carriage bearing support fitting and the forging in the midflap structure to which it attaches (Fig. 502), and by compensating adjustments of the outboard torque tubes relative to the inboard torque tubes. Adding shims will lower the flap trailing edge and removing shims will raise the flap trailing edge. The recommended total shim thickness is 0.20 inch and the allowable shim thickness shall not exceed 0.23 inch. This maximum shim thickness includes shims added for trim correction plus shims installed during assembly and installation of flap. Any increase in shim thickness beyond specified amounts may result in structural damage. The amount of shim or torque tube rotation required for a given amount of trim correction can be determined from Fig. 501. Any raising or lowering of flaps requires checking and rerigging of spoiler to give proper spoiler to flap clearance as required (Ref 27-61-0, A/T and 27-62-0, A/T). Any raising or lowering of flaps also requires checking and readjustment of the outboard flap track fairings (Ref 27-51-121, A/T). Check flap position indication system provides correct visible indication of angular position of flaps (Ref 27-58-01, A/T).
A1.  Equipment and Materials
(1)  Sealant - BMS 5-79, Class C (Ref 20-30-11)
B.  It is essential to verify that a misrigged or out of tolerance system is not giving an incorrect trim reading or flight discrepancy. Prior to determining the amount of adjustment required the following checks shal1 be made.
(1)  
Check that clearance between deflection control ramp and roller at outboard end of midflap is per Fig. 502. Adjust for correct clearance, if required (Ref 27-51-72, R/I).

(2)  
Check that aileron mismatch at indexes and aileron mismatch at outboard rib are within allowable tolerances. Correct aileron system rigging if necessary (Ref 27-11-0, A/T).

NOTE:  To refine airplane trim, use aileron and tab positions at indexes rather than at outboard rib. Tolerances at outboard rib include structural tolerances and may be too large to suit the level of adjustments which must be made. Always use indexes when checking aileron tab mismatch.
　
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