HNA-HNA-26-0618-06B
DPC失效是MAX机型较为典型的一类故障，737MAX-FTD-31-19001有较为详细的论述。但在进近阶段出现安定面马达失去配平灯亮是2025年以来出现的一个新特征。由于安定面马达失去配平灯亮主要和FCC相关，但发生的案例飞机，FCC有V13、V14、V14.1的飞机，因此也排除了FCC软件版本问题导致的可能。由于多轮的沟通，波音均未能构建DPC失效和安定面马达失去配平灯亮之间的关联，需在出现新案例后，再提供案例数据分析。因此基于现有案例共性，作出讨论。
一、案例典型表现
1、STAB OUT OF TRIM灯亮
2、落地恢复显示源电门,右侧DU黑屏
3、OMF状态信息
4、当前故障信息
5、MDS MAINT PAGE— DISPLAYS
6、OMF信息与AHM监控一致
DFCS信息：A通道LEG1
B通道LEG1
60.32 Speed/Stab Trim
二、故障现象的共性分析
| 共性特征 | 出现频次 | 涉及案例 |
| DSPLY SOURCE 2（显示源2故障） | 6/6 | 全部案例 |
| EEC备用灯亮 | 5/6 | 20*S,22*J,22*G,22*X,13*7 |
| 右侧DU黑屏 | 4/6 | 20*S,22*J,22*G,13*7 |
| 左侧ND无导航数据/MAP故障旗 | 5/6 | 20*S,228J,208C,22*X,13*7 |
| VTK（垂直刻度）故障旗 | 4/6 | 20*S,22*J,20*C,22*X |
| STAB OUT OF TRIM灯亮 | 6/6 | 全部案例 |
| GPWS INOP灯亮 | 2/6 | 22*G,20*C |
| SPD LIM/NO AUTOLAND故障旗 | 2/6 | 22*G |
结论：故障现象的共性核心是DPC2失效引发的级联故障链：显示系统故障（SOURCE2）→ 右侧显示屏黑屏 → 左侧导航显示异常 → 安定面配平失控。
三、AHM监控信息的共性分析
| AHM监控信息（共性） | 出现频次 | 涉及案例 |
| 31-00242 DPC-2 HAS AN INTERNAL FAULT | 6/6 | 全部案例 |
| 34-49201 DPC-2 EFIS CP FEEDTHRU 1 BUS INACTIVE | 4/6 | 20*S,22*J,22*X |
| 31-00271 DPC-1 HAS NO INPUT FROM DPC-2 ON FIBER X-TALK CHANNEL B BUS | 5/6 | 22*J,22*X,20*C |
| 31-90012 DPC-2 HAS NO OUTPUT ON MORE THAN ONE BUS | 4/6 | 22*J,22*G,22*X |
| 31-00281 DPC-1 HAS NO INPUT FROM DPC-2 ON CHANNEL 1 X-TALK BUS | 3/6 | 22*J,22*X |
| 31-00042 DPC-2 FAILED BIT ERROR RATE FROM F/O OUTBOARD (ROB) DISPLAY UNIT | 3/6 | 22*X,20*C |
结论：AHM监控的共性是DPC2内部故障（31-00242）是核心告警，伴随DPC1与DPC2之间的X-TALK总线通信中断，以及EFIS CP FEEDTHRU总线失活。
四、OMP状态信息的共性分析
| OMP/OMF状态信息（共性） | 出现频次 | 涉及案例 |
| DPC CROSSTALK BUS 激活状态 | 6/6 | 全部案例 |
| DPC-2 HAS AN INTERNAL FAULT 未激活信息 | 5/6 | 20*S,22*J,22*G,22*X,20*C |
| DPC-2 EFIS CP FEEDTHRU 1 BUS INACTIVE 未激活信息 | 4/6 | 20*S,22*J,22*X,20*C |
结论：OMP状态的共性是DPC CROSSTALK BUS始终处于激活状态，表明DPC1与DPC2之间的交叉通信总线存在持续的通信故障。
五、维护代码的共性分析
| 维护代码 | 故障描述 | 可疑部件 | 出现频次 |
| 22-11375 LCL DPC REVERSION | 本地DPC转换 | MDS/DPC-2 | 6/6 |
| 22-11398 SMYDC DATA INV | SMYDC数据无效 | SMYDC-2 | 6/6 |
| 22-11177 STAB MOTOR | 安定面马达 | PRI ELEC ACT-STAB TRIM | 5/6 |
| 22-11186 TRIM CMD RESPSE MON | 配平指令响应监控 | – | 4/6 |
| 22-11022 BARO ALT INV | 气压高度数据无效 | – | 3/6 |
| 22-11116/22-1114 NO MDS/DPC DATA | MDS/DPC无数据 | MDS/DPC-2 | 2/6 |
结论：DFCS自检的共性是MDS/DPC-2和SMYDC-2是主要可疑部件，安定面马达（STAB MOTOR）相关代码频发，表明DPC2失效直接影响了安定面配平控制。
六、综合结论
1. 根本原因
DPC2（显示处理计算机2）内部故障是导致整个故障链的根本原因。
2. 故障传播机制
DPC2内部故障 (31-00242) → DPC1与DPC2交叉通信中断 (31-00271/281) → DPC2输出总线失效 (31-90012) + EFIS总线失活 (34-49201) → 右侧显示屏黑屏 + 导航数据丢失 → SMYDC-2数据无效 (22-11398) + DPC转换触发 (22-11375) → 安定面配平失控 (STAB OUT OF TRIM)
3.过程分析
典型的AHM报文按时间先后次序
| 状态信息 | 故障信息 | |
| 1 | 316 103 00 DPC CROSSTALK BUS: | 31-00242 DPC-2 HAS AN INTERNAL FAULT |DETECTED BY: DISPLAY PROCESSING COMPUTER (DPC)-2 |
| 2 | 316 302 02 DSPLY SOURCE 2 indication shows on PFD | 31-00242 DPC-2 HAS AN INTERNAL FAULT |DETECTED BY: DISPLAY PROCESSING COMPUTER (DPC)-2 |
| 3 | 344 611 00 GPWS INOP light is on | 34-49201 DPC-2 EFIS CP FEEDTHRU 1 BUS INACTIVE|DETECTED BY:|GROUND PROXIMITY WARNING COMPUTER (GPWC) |
| 4 | 34-45091 | TCAS RESOLUTION ADVISORY 2 STATUS DISCRETE INPUT FAULT FROM DPC-2|DETECTED BY: TRAFFIC COLLISION AVOIDANCE SYSTEM (TCAS) |
| 5 | 31-14370 | DFDAU HAS NO INPUT FROM DPC-2 ON ENG 1 CH B BUS|DETECTED BY: DIGITAL FLIGHT DATA ACQUISITION UNIT (DFDAU) |
| 6 | 31-14480 | DFDAU HAS NO INPUT FROM DPC-2 ON CLOCK-2 BUS|DETECTED BY: DIGITAL FLIGHT DATA ACQUISITION UNIT (DFDAU) |
| 7 | 31-14390 | DFDAU HAS NO INPUT FROM DPC-2 ON ENG 2 CH B BUS|DETECTED BY: DIGITAL FLIGHT DATA ACQUISITION UNIT (DFDAU) |
| 8 | 31-14110 | DFDAU HAS NO INPUT FROM DPC-2 ON MDS-GP1 BUS|DETECTED BY: DIGITAL FLIGHT DATA ACQUISITION UNIT (DFDAU) |
| 9 | 34-21130 | ADIRU-L HAS NO INPUT FROM DPC-2 ON BARO CORR 2 BUS|DETECTED BY: AIR DATA INERTIAL REFERENCE UNIT (ADIRU)-LEFT |
| 10 | 34-22129 | ADIRU-R HAS NO INPUT FROM DPC-2 ON BARO CORR 1 BUS|DETECTED BY: AIR DATA INERTIAL REFERENCE UNIT (ADIRU)-RIGHT |
| 11 | 46-11107 | NFS-L HAS NO INPUT FROM DPC-1 ON ETHERNET SWITCH PORT 7 |DETECTED BY: NETWORK FILE SERVER (NFS-L) |
| 12 | 34-43105 | WXR PROCESSOR 1 HAS NO INPUT FROM DPC-2 F/O EFIS RANGE BUS|DETECTED BY: WXR PROCESSOR 1 |
| 13 | 46-11108 | NFS-L HAS NO INPUT FROM DPC-2 ON ETHERNET SWITCH PORT 8 |DETECTED BY: NETWORK FILE SERVER (NFS-L) |
| 14 | 52-72018 | PSEU NO ENGINE 2 RUNNING RELAY SIGNAL |
| 15 | 27-31021 | DPC/DEU DATA INVALID|DETECTED BY: STALL MANAGEMENT YAW DAMPER (SMYD)-1 |
| 16 | 34-31511 | MMR-1 HAS NO OMF INPUT FROM DPC-1 ON MDS-GP2 BUS|DETECTED BY: MULTI-MODE RECEIVER (MMR)-1 |
| 17 | 34-31512 | MMR-2 HAS NO OMF INPUT FROM DPC-2 ON MDS-GP2 BUS|DETECTED BY: MULTI-MODE RECEIVER (MMR)-2 |
| 18 | 46-12008 | NFS-L HAS NO INPUT FROM DPC-2 ON ARINC 429 RX PORT 8 |DETECTED BY: NETWORK FILE SERVER (NFS-L) |
| 19 | 34-62651 | FMC-1 HAS NO INPUT FROM DPC-2 ON DPC-FMC OUTPUT BUS |DETECTED BY: FLIGHT MANAGEMENT COMPUTER (FMC)-1 |
| 20 | 34-62652 | FMC-2 HAS NO INPUT FROM DPC-2 ON DPC-FMC OUTPUT BUS |DETECTED BY: FLIGHT MANAGEMENT COMPUTER (FMC)-2 |
3. 关键结论
| 序号 | 结论内容 |
| 1 | 核心故障件：DPC-2是确定性故障源，6个案例100%出现31-00242告警 |
| 2 | 级联影响：DPC2失效后，通过交叉总线（X-TALK BUS）影响DPC1，导致显示系统全面故障 |
| 3 | 安定面配平失控的直接原因：DPC2失效→ SMYDC-2数据无效→ 安定面配平系统失去正确的数据输入→ 触发OUT OF TRIM警告 |
| 4 | 故障发生阶段：多发生在巡航（Cruise）和进近（Approach）阶段，与飞行阶段无直接相关性 |
附案例汇总：
| 机号 | 故障现象 | 故障信息 |
| 20** | 出现DSPLY SOURCE2 ，EEC备用灯亮，右侧两个DU黑屏，左侧ND无导航数据，左侧ND显示MAP VTK，五边盲降截获后出现STAB OUT OF TRIM灯亮 | AHM监控有： MMSG 34-49201 DPC-2 EFIS CP FEEDTHRU 1 BUS INACTIVE MMSG 31-00242 Intermittent(2) DPC-2 HAS AN INTERNAL FAULT |DETECTED BY: DISPLAY PROCESSING COMPUTER (DPC)-2OMF状态信息有DPC1、DPC CROSSTALK BUS信息，当前有未激活信息31-00242 DPC-2 HAS AN INTERNAL FAULT |DETECTED BY: DISPLAY PROCESSING COMPUTER (DPC)-2，34-49201 DPC-2 EFIS CP FEEDTHRU 1 BUS INACTIVE，有激活的DPC CROSSTALK BUS信息。复位DPC1信息，恢复正常，测试正常。DFCS自检当前正常，历史B通道LEG1有22-11375 LCL DPC REVERSION信息（可疑部件MDS/DPC-2信息）、22-11398 SMYDC DATA INV（可疑部件SMYDC-2信息），历史A通道LEG1有22-11186 TRIM CMD RESPSE MON、22-11177 STAB MOTOR信息。 |
| 22** | 显示源2信息，右侧两个DU黑屏，左侧出现VTK和MAP故障旗.进近3000FT左右出现安定面配平OUT OF TRIM灯闪亮一次，过一会再次亮起 | AHM监控有: MMSG 31-01642 Intermittent(1) DPC-2 HAS NO INPUT FROM FMC-2 ON FMC RIGHT BUS|DETECTED BY: DISPLAY PROCESSOR COMPUTER (DPC)-2 MMSG 31-00242 Intermittent(5) DPC-2 HAS AN INTERNAL FAULT |DETECTED BY: DISPLAY PROCESSING COMPUTER (DPC)-2 MMSG 34-49201 Intermittent(2) DPC-2 EFIS CP FEEDTHRU 1 BUS INACTIVE MMSG 31-90012 Intermittent(1) DPC-2 HAS NO OUTPUT ON MORE THAN ONE BUS MMSG 31-01642 Intermittent(1) DPC-2 HAS NO INPUT FROM FMC-2 ON FMC RIGHT BUS|DETECTED BY: DISPLAY PROCESSOR COMPUTER (DPC)-2 MMSG 31-00271 Intermittent(1) DPC-1 HAS NO INPUT FROM DPC-2 ON FIBER X-TALK CHANNEL B BUS|DETECTED BY: DISPLAY PROCESSING COMPUTER (DPC)-1 MMSG 31-00281 Intermittent(1) DPC-1 HAS NO INPUT FROM DPC-2 ON CHANNEL 1 X-TALK BUS|DETECTED BY: DISPLAY PROCESSING COMPUTER (DPC)-1OMF状态信息有DPC1、DPC CROSSTALK BUS信息，当前有未激活信息31-00242 DPC-2 HAS AN INTERNAL FAULT |DETECTED BY: DISPLAY PROCESSING COMPUTER (DPC)-2，34-49201 DPC-2 EFIS CP FEEDTHRU 1 BUS INACTIVE，有激活的DPC CROSSTALK BUS信息。复位DPC1信息，恢复正常，测试正常。DFCS自检当前正常，历史B通道LEG1有22-11375 LCL DPC REVERSION信息（可疑部件MDS/DPC-2信息）、22-11398 SMYDC DATA INV（可疑部件SMYDC-2信息），历史A通道LEG1有22-11186 TRIM CMD RESPSE MON、22-11177 STAB MOTOR信息 |
| 22** | 右侧显示屏间歇性故障。稳定后出现DSPLY SOURCE 2故障，同时双发EEC、GND PROX灯亮SPD LIM和NO AUTOLAND故障旗出现。下降过程中，高度2700米左右，STAB OUT OF TRIM灯亮 | DPC CROSSTALK BUS信息，GPWS INOP灯亮，OMF有FDE：DSPLY SOURCE2、DPC CROSSTALK BUS、GPWS INOP、ENG 2 EEC C2和ENG 1 EEC C2，对应的激活的维护信息31-90012 DPC-2 HAS NO OUTPUT ON MORE THAN ONE BUS|DETECTED BY:|DISPLAY PROCESSING COMPUTER (DPC)-1|NETWORK FILE SERVER (NFS)-LEFT，复位DPC2跳开关信息信息消失。GPWS历史1段故障EFIS BUS INVALD，DFCS自检历史*STAB TRM*对应故障信息22-11177 STAB MOTOR，可疑部件PRI ELEC ACT-STAB TRIM，完成SPD/STB TRIM库测试通过，*NO AUTOLND*对应故障信息22-1116/22-1114 NO MDS/DPC DATA，可疑部件MDS/DPC-2 。*CRZ PB0V*对应故障信息22-11398 SMYDC DATA INV，可疑部件SMYDC-2。 |
| 22** | 显示源2故障，EEC备用灯亮。进近时安定面失去配平灯亮 | AHM监控31-00042 DPC-2 FAILED BIT ERROR RATE FROM F/O OUTBOARD (ROB) DISPLAY UNIT31-00032 DPC-2 FAILED BIT ERROR RATE FROM F/O INBOARD (RIB) DISPLAY UNIT316 302 02 DSPLY SOURCE 2 indication shows on PFD31-00271 DPC-1 HAS NO INPUT FROM DPC-2 ON FIBER X-TALK CHANNEL B BUS31-00242 DPC-2 HAS AN INTERNAL FAULT316 103 00 DPC CROSSTALK BUS: Status message shows31-00271 DPC-1 HAS NO INPUT FROM DPC-2 ON FIBER X-TALK CHANNEL B BUS31-00291 DPC-1 HAS NO INPUT FROM DPC-2 ON CHANNEL 2 X-TALK BUS31-00371 DPC-1 HAS NO INPUT FROM DPC-2 ON FIBER X-TALK CHANNEL A BUS31-00242 DPC-2 HAS AN INTERNAL FAULT732 611 51 EEC ALTN light: comes on- engine 131-90012 DPC-2 HAS NO OUTPUT ON MORE THAN ONE BUS732 611 52 EEC ALTN light: comes on- engine 231-90012 DPC-2 HAS NO OUTPUT ON MORE THAN ONE BUS维护信息如下： MMSG31-90012 Hard 飞行阶段：Cruise DPC-2 HAS NO OUTPUT ON MORE THAN ONE BUS|DETECTED BY:|DISPLAY PROCESSING COMPUTER (DPC)-1 MMSG31-01642 Intermittent(1)飞行阶段：Cruise DPC-2 HAS NO INPUT FROM FMC-2 ON FMC RIGHT BUS|DETECTED BY: DISPLAY PROCESSOR COMPUTER (DPC)-2 MMSG34-49201 Intermittent(1)飞行阶段：Cruise DPC-2 EFIS CP FEEDTHRU 1 BUS INACTIVE|DETECTED BY:|GROUND PROXIMITY WARNING COMPUTER (GPWC) MMSG31-00372 Intermittent(1)飞行阶段：Cruise DPC-2 HAS NO INPUT FROM DPC-1 ON FIBER X-TALK CHANNEL A BUS|DETECTED BY: (DPC)-2 MMSG31-00271 Intermittent(1)飞行阶段：Cruise DPC-1 HAS NO INPUT FROM DPC-2 ON FIBER X-TALK CHANNEL B BUS|DETECTED BY: (DPC)-1 MMSG31-00281 Intermittent(1)飞行阶段：Cruise DPC-1 HAS NO INPUT FROM DPC-2 ON CHANNEL 1 X-TALK BUS|DETECTED BY: (DPC)-1 MMSG31-00242 Intermittent(2)飞行阶段：Cruise DPC-2 HAS AN INTERNAL FAULT |DETECTED BY: DISPLAY PROCESSING COMPUTER (DPC)-2DFCS自检当前正常，A通道历史LEG1有22-11177 STAB MOTOB。B通道历史LEG1有22-11375 LCL DPC REVERSION（可疑部件MDS/DPC-2）、22-11398 SMYDC DATA INV（可疑部件SMYD-2）、22-11022 BARO ALT INV。 |
| 20** | 右侧ND和PFD黑屏，左侧PFD有DISPLAY SOURCE2信息，左侧ND无航路显示，有VTK和MAP故障旗，EEC备用灯点亮，近地警告INOP灯亮。进近阶段STAB OUT OF TRIM灯闪亮 | AHM:31-00042 DPC-2 FAILED BIT ERROR RATE FROM F/O OUTBOARD (ROB) DISPLAY UNIT31-00031 DPC-1 FAILED BIT ERROR RATE FROM F/O INBOARD (RIB) DISPLAY UNIT316 103 00 DPC CROSSTALK BUS: Status message shows31-00242 DPC-2 HAS AN INTERNAL FAULT316 302 02 DSPLY SOURCE 2 indication shows on PFD31-00242 DPC-2 HAS AN INTERNAL FAULTOMF历史有DPC-2 HAS AN INTERNAL FAULT、DPC-2 FAILED BIT ERROR RATE FROM F/O OUTBOARD (ROB) DISPLAY UNIT、DPC-2 FAILED BIT ERROR RATE FROM F/O INBOARD (RIB) DISPLAY UNIT、FMC-2 HAS NO INPUT FROM DPC-2 ON DPC-FMC OUTPUT BUS、FMC-1 HAS NO INPUT FROM DPC-2 ON DPC-FMC OUTPUT BUS 信息。A通道历史LEG01段有22-11177 STAB MOTOR和22-11186 TRIM CMD RESPSE MON信息，B通道历史LEG01段有22-11022BARO ALT INV、22-11398 SMYDC DATA INV和22-11375 LCL DPC REVERSION信息， |
| 13** | 右侧两个显示屏先闪烁，后出现DISPLAY SOURCE2故障旗，EEC备用灯亮.进近阶段STAB OUT OF TRIM灯灯闪亮 | 当前状态有22-11116 NO MDS/DPC DATA故障信息，复位DPC2跳开关，再次完成DFCS自检测试，当前状态测试正常，A通道历史LEG01段有22-11177 STAB MOTOR和22-11186 TRIM CMD RESPSE MON信息，B通道历史LEG01段有22-11022 BARO ALT INV、22-11398 SMYDC DATA INV和22-11375 LCL DPC REVERSION信息 |