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 22-12-01
 YAW DAMPER COUPLER  ú ú 02 Page 122 ú Jul 12/01 
BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details. 
A 
737-300/400/500MAINTENANCE MANUAL
 ~............................................................................... | FAULT MESSAGE/CORRECTIVE ACTION (TABLE 101) | ................................................................................. | YDC Fault | YDC Fault | Corrective Action | | Message | Detail 1 | | .................................................................................
 | prgm  | msg. no.  | Possible Causes:  | 
 | pin  | 22-21023  | 1. Program pins do not match airplane type  | 
 | fault  |  | selected during YDC BITE Program Pin Test  | 
 |  |  | 2. Operator error  | 
 |  |  | 3. Airplane wiring  | 
 |  |  | 4. Yaw Damper Coupler  | 
 |  |  |  | 
 |  |  | Corrective Action:  | 
 |  |  | 1. Inspect D295 pin 17 and D295 pin 53 and YDC  | 
 |  |  | electrical connector for bent or broken pins,  | 
 |  |  | contamination, or damage.  | 
 |  |  | 2. Make sure that D295 pin 17 and D295 pin 53  | 
 |  |  | resistance to ground is consistent with airplane  | 
 |  |  | wiring diagrams:  | 
 |  |  |  | 
 |  |  | 737 Model D295 Pin 53 D295 Pin 17  | 
 |  |  | -500 GROUND GROUND  | 
 |  |  | -400 OPEN GROUND  | 
 |  |  | -300 OPEN GROUND  | 
 |  |  |  | 
 |  |  | 3. Perform Yaw Damper Coupler - Adjustment/Test  | 
 |  |  | (AMM 22-12-01/501).  | 
 |  |  | 4. If the problem is not corrected, replace the  | 
 |  |  | Yaw Damper Coupler (AMM 22-12-31/401).  |
................................................................................. | A hyd lo | msg. no. | Possible Causes: | | on fault | 22-21025 | 1. Flt Control A Low Pressure light did not | | | | illuminate during YDC BITE Pressure Reducer Test | | | | 2. Operator error | | | | 3. Flt Control A Low Pressure light inoperative | | | | 4. Yaw Damper Coupler | | | | | | | | Corrective Action: | | | | 1. Make sure that Flt Control A switch is in the ON | | | | position. | | | | 2. Make sure that Flt Control A light illuminates, | | | | press to test. | | | | 3. Do a wiring check between D295 pin 57 and Flt | | | | Control A Low Pressure light. | | | | 4. Inspect D295 pin 57 and YDC electrical connector | | | | for bent or broken pins, contamination, or damage. | | | | 5. Perform Yaw Damper Coupler - Adjustment/Test | | | | (AMM 22-12-32/501). | | | | 6. If the problem is not corrected, replace the | | | | Yaw Damper Coupler (AMM 22-12-31/401). | 中国航空网 www.aero.cn 航空翻译 www.aviation.cn 本文链接地址:737-300 400 500 AMM 飞机维护手册 自动飞行 AUTOFLIGHT 2(94)