SB-737-27-1317
背景原因：在针对SCE部件的NFF的调查过程中，供应商BAE发现SCE不符合波音SCD（Specification Control Drawing）要求。SCD要求，单一故障不能引起超过1对的飞行扰流板失效。审查发现SCE中内部1个+/-15V电源（数量4）的失效，将导致所有4对飞扰的失效。需要进行硬件更改，以更好将单个失效与整体故障隔离开。新的SCE零件号115E6352G3，并将包含确保完全符合SCD要求所需的硬件。
因此免费对115E6352G1/2进行升级。机队EO已下，适用20架飞机。
案例：2025年1月，有MAX飞机航前通电后MAINT灯亮，并有SPOILER PAIR 5/8、4/9、3/10、2/11以及 SPOILER CONTROL CHANNEL状态信息，OMF有27-01000/27-01650/27-01660/27-01680/27-01690维护信息。
从CMM看下图的4个板卡都做了设计上的更改。
HNA-HNA-24-2507-08B和网络公众号
2025年1月，有飞机发生N1参数摆动的故障，自检右发EEC有75-20392 VSV Position Signal is Out of Range长时故障信息和75-30402 VSV Position Signals Disagree短时故障信息。
摆动共发生4次，典型的数据如下所示：
排故更换了左右作动器、HMU、EEC。
从故障的根本原因分析，应该是左侧作动器（B通道）LVDT故障原因导致。正常情况下，EEC使用A通道和B通道，即左侧和右侧作动器LVDT的反馈值来综合计算。当判定一个通道不可用的时候，则使用工作正常的那个通道的数据。这类失效模式，分析是其中一个LVDT提供了虚假的数据，但EEC并未判定其不可用，而是参与了计算。从而得到一个未到位的结论，给出了VSV做动的错误指令。从而导致气流通道的瞬时停滞，引气PS3的变小，FF变小。发动机为维持N1值，马上主动提供FF，出现短时富油燃烧。
波音的分析，更趋向于 VSV Bellcrank的磨损，认为磨损的Bellcrank可以使超出范围的信息激活，并使通道失能。在实际的排故检查中除衬套轻微磨损外，并未发现主连杆的磨损。也没有发现空行程的存在。
针对该故障，有几个在分析和讨论中的要点提出来：
一、是否存在喘振
从结果看，有喷火，有放炮声，都认为存在喘振的情况。但CFM厂家在对数据进行分析后，认为不存在喘振。
A5. Please be informed CFM has reviewed QAR data and confirms ENG 2 VSV position having a noisy signal which can affect erroneous VSV scheduling. CFM does not observe any engine stall and CFM confirms fuel package is behaving as expected. CFM recommends performing FIM task for the related Fault codes which can be aligned to flight observations. A brief summary of QAR analysis is being attached.
从喘振的定义看，发动机喘振是指发动机压气机在非正常工况下，气流沿压气机轴线方向发生的低频率（通常几赫兹到十几赫兹）、高振幅的气流振荡现象。这种现象通常表现为气流的周期性倒流，即气流在压气机内时而向前流动，时而倒流，导致压气机出口压力和流量出现大幅度波动。
从数据看，仅发生一秒的数据波动，并未发现反复振荡的现象。因此认同厂家对于并未发生喘振的判断。
二、LVDT的基本工作原理
1、 LVDT（线性可变差动变压器）是一种基于电磁感应原理的位移传感器，其工作原理主要基于法拉第电磁感应定律。LVDT由一个初级线圈、两个次级线圈和一个可移动的铁芯组成。初级线圈和次级线圈绕制在线圈骨架上，铁芯可以在中空的线圈内自由移动。
LVDT 的初级绕组 P 由恒定振幅交流电源进行通电。由此形成的磁通量由纤芯耦合到相邻的次级绕组 S1 和 S2。如果纤芯位于 S1 和 S2 的中间，则会向每个次级绕组耦合相等的磁通量，因此绕组 S1 和 S2 中各自包含的 E1 和 E2 是相等的。在该参考中间纤芯位置（称为零点），差分电压输出 (E1 – E2) 本质上为零。
如果移动纤芯，使其与 S1 的距离小于与 S2 的距离，则耦合到 S1 中的磁通量会增加，而耦合到 S2 中的磁通量会减少，因此感生电压 E1 增大，而 E2 减小，从而产生差分电压 (E1 – E2)。相反，如果纤芯移动得更加靠近 S2，则耦合到 S2 中的磁通量会增加，而耦合到 S1 中的磁通量会减少，因此 E2 增大，而 E1 减小，从而产生差分电压 (E2 – E1)。
2、VSV的LVDT
从波音的SR回复可以知道，做动筒的伸出长度是 从0 (fully retracted) to approximately 3.5 fully extended，对应VSV指示的角度是从 -5 degrees to 40 degrees。
从VSV的CMM可以看出，测试的时候，外接电源向主线圈提供的电源为7.07（正负 0.14） VAC RMS（Root Mean Square，是一个用来描述交流（AC）信号大小的量度，它表示交流信号在一个周期内的平均功率与相同功率的直流（DC）信号的电压或电流值。），3000HZ (正负300 Hz) ， 30 mA max的供电。推测EEC的供电也是这个品质。
次级线圈1和线圈2，分别产生一个输出电压。在伸出过程中V1值变大，V2的值变小。收回时，反之亦然。
测试中的范围为：（从得值可以看出，在伸出的时候磁芯离S1线圈近一些，收上的时候S2线圈离线芯近一些，但整体还是S1线圈更近，出现正负值，只不过是电流方向变化而已。）
3、故障代码的含义
1）代码75-X040Y表示通道间LVDT差值超标（0.3inch）但满足指令值标准（与指令差值小于5%）。
2、代码75-X039Y表示X通道探测到VSV的LVDT反馈信号超限。该代码主要由于作动筒LVDT到EEC的阻值超标导致。
具体表示：
①VSV的位置信号指示小于-0.09英寸或大于3.62英寸；
②V1、V2（在输入监控页可看到）任一小于0.313V或任一大于7.205V；
③V1+V2小于4.0V或大于6.5V。
3、代码75-X038Y表示X通道探测到VSV的指令值与反馈值不一致，差异大于5.78%，且没有探测到HMU中马达故障；
4、 代码75-X037Y表示HMU中VSV马达返回EEC线路的电流超标，或者EEC到HMU中VSV马达的电流与返回电流差值绝对值超标。
三、解决办法探讨
1、收紧组合代码的放行。代码来源于两个方面，一个方面是通过航后自检的方式获取，一个是通过报文下传，因为EEC的ICD文件尚未获得，实时报文尚未建立。从历史数据看组合数据累积发生28起，数量如下。按严控的半夜也可以接受。但并非所有的组合数据均会发生。且发生的案例中，一般都在1-2段后出现，给航后读取方式的获取带来困难。
2009：2；2014：1；2019：1；2021：7；2022：2；2023：5；2024：10；2025：1
2、使用QAR数据进行抓取。逻辑原理就是在运行过程中如果该发的参数较另外一台发动机的参数，出现反复低频摆动，作为警告。这种方式有一定的可行性，但会生成较多的干扰报文。因为受推力变化、左右发性能差异、某些空行程、外部环境等。需要谨慎使用，否则会带来机队的较多的工作量。
典型的波动数据如下图所示。
3、利用单台发动机的A/B通道值，进行自身对比。这应该是最有效的监控手段。由于DAR记录的是综合计算值是不可用的。只能看通过ACMS实时报文有没有可能。由于现有的文档规范，仅给出了如下的，从规范看，应该也取得是综合值。因为从CDU能读出A通和B通的分别参数，因此只能从其他途径看有没有可能获得。
2025年1月，有15*2飞机反应下防撞灯不亮，三个频闪灯不亮。受MEL限制无法放行。
这两路的供电和控制是完全独立的线路，且上/下防撞灯使用相同的供电源。因此有一定概率是两套系统同时失效的可能。
1、经过对防撞灯供电的测量，发现供电组件上游也没有电，量线发现供电线路存在断路。
2、对频闪灯电门，使用线路直连，也不能点亮。
转而看两者的物理上接近的情况，供电上有共同经过D40506P插头的情况。一个是使用B2、一个是A3。
通过的使用D40506P插头的系统验证，发现还有一个系统，前货舱火警A环路故障。
因此，重点检查D40506插头和插座，在E2-2架接近后。发现存在烧蚀的情况。
实际拆下后，发现A3钉烧蚀严重，其他钉并未发现明显的烧蚀。
因此分析烧蚀的源头为下防撞灯供电线路，产生的短路烧蚀。其他两个临近插钉，应该是烧蚀对旁边胶片的挤压影响了连接性，表明触点实际是比较敏感的。
进一步看D40506上下游，上游为跳开关C111,件号BACC18AD5,为5安培；下游为M1745供电组件。
针对该线路，查询FTD和FIX均无相关案例说明。插头机队未有过订料历史。
附：检查导图
来自于网络公众号
| 章节 | 跳开关 | 面板 | 位置 |
| 21 | A/C OVERBOARD EXH VALVE RECONFIG CONT | P6-4 | D2 |
| 21 | A/C OVERBOARD EXHAUST VALVE CONT | P6-4 | D1 |
| 21 | A/C PACK/ENGINE BLEED AIR OVHT LEFT | P6-4 | C8 |
| 21 | A/C PACK/ENGINE BLEED AIR OVHT RIGHT | P6-4 | C7 |
| 21 | A/C RECIRC FAN LEFT CABIN AIR | P18-3 | E7 |
| 21 | A/C RECIRC FAN LEFT CONT | P18-3 | E9 |
| 21 | A/C RECIRC FAN RIGHT CONT. | P6-4 | E2 |
| 21 | A/C TEMP CONT VALVE CLOSE LEFT | P6-4 | A1 |
| 21 | A/C TEMP CONT VALVE CLOSE RIGHT | P6-4 | B1 |
| 21 | A/C ZONE TEMP DUCT OVHT AFT PASS | P6-4 | C2 |
| 21 | A/C ZONE TEMP DUCT OVHT FLT DECK | P6-4 | C4 |
| 21 | A/C ZONE TEMP DUCT OVHT FWD PASS | P6-4 | C3 |
| 21 | A/C ZONE TEMP VALVE/FAN CONT AFT PASS | P6-4 | A3 |
| 21 | A/C ZONE TEMP VALVE/FAN CONT FLT DECK | P6-4 | B3 |
| 21 | A/C ZONE TEMP VALVE/FAN CONT FWD PASS | P6-4 | B2 |
| 21 | AC RECIRC FAN RIGHT CABIN AIR | P6-4 | E4 |
| 21 | AIR COND PACK CONT VALVES L ALT | P6-4 | D3 |
| 21 | AIR COND PACK CONT VALVES R ALT | P6-4 | D4 |
| 21 | AIR CONDITIONING DOOR AREA HEAT CONT | P18-3 | E11 |
| 21 | AIR CONDITIONING PACK CONT RIGHT AC | P6-4 | B11 |
| 21 | AIR CONDITIONING PACK CONT RIGHT DC | P6-4 | B9 |
| 21 | AIR CONDITIONING PACK CONT VALVES L | P6-4 | C6 |
| 21 | AIR CONDITIONING PACK CONT VALVES R | P6-4 | C5 |
| 21 | AIR CONDITIONING PACK CONTROL LEFT AC | P6-4 | A11 |
| 21 | AIR CONDITIONING PACK CONTROL LEFT DC | P6-4 | A9 |
| 21 | AIR CONDITIONING RAM AIR MOD CONT L | P6-4 | A8 |
| 21 | AIR CONDITIONING RAM AIR MOD CONT R | P6-4 | B8 |
| 21 | AIR CONDITIONING RAM AIR MOD LEFT | P6-4 | A4 |
| 21 | AIR CONDITIONING RAM AIR MOD LEFT | P6-4 | A4 |
| 21 | AIR CONDITIONING RAM AIR MOD RIGHT | P6-4 | B4 |
| 21 | AIR CONDITIONING RAM AIR MOD RIGHT | P6-4 | B4 |
| 21 | AIR CONDITIONING TEMP IND | P6-4 | D8 |
| 21 | AIR CONDITIONING TRIM AIR PRESS | P6-4 | D9 |
| 21 | DOOR AREA HTR-AFT | P91 | A14 |
| 21 | DOOR AREA HTR-AFT | P91 | D7 |
| 21 | DOOR AREA HTR-FWD | P91 | A16 |
| 21 | DOOR AREA HTR-FWD | P91 | D9 |
| 21 | EQPT CLG EXH FAN PWR-ALTN | P92 | A10 |
| 21 | EQPT CLG EXH FAN PWR-ALTN | P92 | D12 |
| 21 | EQPT CLG EXH FAN PWR-NORM | P91 | E1 |
| 21 | EQPT CLG SPLY FAN PWR-ALTN | P91 | A8 |
| 21 | EQPT CLG SPLY FAN PWR-NORM | P92 | A8 |
| 21 | EQPT CLG SPLY FAN PWR-NORM | P92 | D10 |
| 21 | EQPT COOLING EXHAUST FAN CONT ALTN | P6-4 | C15 |
| 21 | EQPT COOLING EXHAUST FAN CONT NORMAL | P6-4 | C14 |
| 21 | EQPT COOLING LOW FLOW DETECT EXHAUST | P18-3 | A18 |
| 21 | EQPT COOLING LOW FLOW DETECT SUPPLY | P18-3 | A17 |
| 21 | EQPT COOLING SUPPLY FAN CONT-NORMAL | P6-4 | C12 |
| 21 | EQPT COOLING SUPPLY FAN CONTROL-ALTN | P6-4 | C13 |
| 21 | MID EXIT DOOR AREA HEATER | P6-12 | D5 |
| 21 | PRESSURIZATION CONTROL AUTO 1 | P6-4 | F3 |
| 21 | PRESSURIZATION CONTROL AUTO 2 | P6-4 | F5 |
| 21 | PRESSURIZATION CONTROL IND | P6-4 | F7 |
| 21 | PRESSURIZATION CONTROL LCD LTG | P6-4 | F1 |
| 21 | PRESSURIZATION CONTROL MANUAL | P6-4 | F6 |
| 22 | AFCS INTLK 2 | P6-2 | A3 |
| 22 | AFCS MCP DC 1 | P18-1 | D5 |
| 22 | AFCS MCP DC 2 | P6-2 | C3 |
| 22 | AFCS STABILIZER TRIM | P18-1 | C2 |
| 22 | AFCS SYS A ENGAGE INTLK | P18-1 | D3 |
| 22 | AFCS SYS A FCC DC | P18-1 | D2 |
| 22 | AFCS SYS A MACH TRIM AC | P18-1 | C4 |
| 22 | AFCS SYS A MACH TRIM DC | P18-1 | D4 |
| 22 | AFCS SYS A RUDDER DC (INOP) | P18-1 | E4 |
| 22 | AFCS SYS A SNSR EXC AC | P18-1 | C5 |
| 22 | AFCS SYS A WARN LIGHT (BAT) | P18-1 | D1 |
| 22 | AFCS SYS B ENGAGE INTLK | P6-2 | B4 |
| 22 | AFCS SYS B FCC DC | P6-2 | B3 |
| 22 | AFCS SYS B MACH TRIM AC | P6-2 | C1 |
| 22 | AFCS SYS B MACH TRIM DC | P6-2 | B2 |
| 22 | AFCS SYS B RUDDER DC (INOP) | P6-2 | D3 |
| 22 | AFCS SYS B SNSR EXC AC | P6-2 | C2 |
| 22 | AFCS SYS B WARN LIGHT (BAT) | P6-2 | B1 |
| 22 | AUTOTHROTTLE DC 1 | P18-1 | E1 |
| 22 | YAW DAMPER 1 DC | P18-1 | D7 |
| 22 | YAW DAMPER 2 DC | P18-1 | D6 |
| 22 | YAW DAMPER AC | P18-1 | C7 |
| 22 | YAW DAMPER IND | P18-1 | C6 |
| 23 | ACARS CMU DC | P6-1 | E9 |
| 23 | ACARS MU AC (INOP) | P6-1 | E7 |
| 23 | ACARS MU DC (INOP) | P6-1 | E8 |
| 23 | AIRSHOW AC | P6-1 | B11 |
| 23 | ATTENDANT PANELS | P6-1 | D12 |
| 23 | AUDIO CAPT | P6-2 | D23 |
| 23 | AUDIO F/O | P6-2 | D22 |
| 23 | AUDIO OBS | P6-2 | D24 |
| 23 | CMU-1 AC | P6-1 | E8 |
| 23 | CMU-1 AC (INOP) | P6-1 | E8 |
| 23 | CMU-2 AC | P6-1 | E7 |
| 23 | CMU/ACARS DC | P6-1 | E9 |
| 23 | CMU/ACARS DC (INOP) | P6-1 | E9 |
| 23 | COMMUNICATIONS HF 1 | P18-2 | E11 |
| 23 | COMMUNICATIONS HF 1 (INOP) | P18-2 | E11 |
| 23 | COMMUNICATIONS HF 2 | P6-1 | D2 |
| 23 | COMMUNICATIONS HF 2 (INOP) | P6-1 | D2 |
| 23 | COMMUNICATIONS PA AMPL BAT | P6-1 | D4 |
| 23 | COMMUNICATIONS SELCAL | P18-2 | D15 |
| 23 | COMMUNICATIONS SELCAL (INOP) | P18-2 | D15 |
| 23 | COMMUNICATIONS VHF 1 | P18-2 | D11 |
| 23 | COMMUNICATIONS VHF 2 | P6-1 | C3 |
| 23 | COMMUNICATIONS VHF 3 | P18-2 | D12 |
| 23 | ELT INTERFACE UNIT (INOP) | P6-3 | C1 |
| 23 | ENT VID CONT CENTER AC | P6-1 | C7 |
| 23 | ENT VID CONT CENTER AC (INOP) | P6-1 | C7 |
| 23 | ENT VID CONT CENTER DC | P6-1 | C5 |
| 23 | ENT VID CONT CENTER DC (INOP) | P6-1 | C5 |
| 23 | ENTERTAINMENT AUDIO | P6-1 | C8 |
| 23 | ENTERTAINMENT AUDIO (INOP) | P6-1 | C8 |
| 23 | ENTERTAINMENT AUDIO DC | P6-1 | B10 |
| 23 | ENTERTAINMENT AUDIO DC (INOP) | P6-1 | B10 |
| 23 | ENTERTAINMENT PA SYS BAT | P6-1 | C6 |
| 23 | ENTERTAINMENT PA TAPE RPDR AC | P6-1 | C9 |
| 23 | ENTERTAINMENT PWR CTRL | P6-1 | B10 |
| 23 | INTERPHONE POWER CAPT BAT | P6-2 | C24 |
| 23 | INTERPHONE POWER CAPT DC 2 | P6-2 | C23 |
| 23 | INTERPHONE POWER F/O BAT | P6-2 | C22 |
| 23 | INTERPHONE POWER F/O DC 2 | P6-2 | C21 |
| 23 | INTPH AND WARN | P6-2 | D21 |
| 23 | IVS HEAD-END | P6-1 | B9 |
| 23 | PASSENGER CABIN CREW CALL | P18-3 | A9 |
| 23 | SATCOM AURAL WARN | P18-2 | E15 |
| 23 | SATCOM HIGH | P18-2 | E14 |
| 23 | SATCOM SDU | P18-2 | E13 |
| 23 | SATCOM SDU | P18-2 | E13 |
| 23 | SURVEILLANCE CAMERA | P6-12 | B1 |
| 23 | VIDEO 1 | P6-1 | D5 |
| 23 | VIDEO 1 (INOP) | P6-1 | D5 |
| 23 | VIDEO 2 | P6-1 | D6 |
| 23 | VIDEO 2 (INOP) | P6-1 | D6 |
| 23 | VIDEO 3 | P6-1 | D7 |
| 23 | VIDEO 3 (INOP) | P6-1 | D7 |
| 23 | VIDEO 4 | P6-1 | D8 |
| 23 | VIDEO 4 (INOP) | P6-1 | D8 |
| 23 | VOICE RCDR | P18-2 | D7 |
| 23 | VOICE RCDR RELAY | P18-2 | C7 |
| 23 | VOICE RCDR RELAY (INOP) | P18-2 | C7 |
| 23 | VOICE RCDR/RIPS | P18-2 | D6 |
| 24 | 28V AC GND SERV 1 | P91 | E11 |
| 24 | 28V AC GND SERV 1 | P91 | E12 |
| 24 | 28V AC GND SERV 2 | P92 | E6 |
| 24 | 28V AC XFR BUS 1 | P91 | B10 |
| 24 | 28V AC XFR BUS 1 SECT 2 | P18-3 | C5 |
| 24 | 28V AC XFR BUS 2 | P92 | B10 |
| 24 | AC APU GEN IND | P91 | B11 |
| 24 | AC BUS 28V AC XFR BUS 2 SECT 2 | P6-4 | D14 |
| 24 | AC BUS AC STBY BUS PWR | P6-4 | D18 |
| 24 | AC BUS STBY BUS 115V AC IND | P6-4 | D16 |
| 24 | AC BUS STBY BUS 28V AC DISTR | P6-4 | D15 |
| 24 | AC BUS XFR BUS 2 115V AC IND | P6-4 | D13 |
| 24 | AC GEN 1 IND | P91 | B12 |
| 24 | AC GEN 2 IND | P92 | B12 |
| 24 | APU GEN CONT UNIT | P92 | C9 |
| 24 | AUX BAT CHARGER | J9 | A3 |
| 24 | AUX BAT CHGR | P91 | E3 |
| 24 | AUX BAT DC VOLTMETER | J9 | A2 |
| 24 | AUXILIARY POWER BREAKER | P91 | — |
| 24 | BAT BUS SECT 1 | M01720 | C4 |
| 24 | BAT BUS SECT 2 | M01720 | C5 |
| 24 | BAT BUS SECT 3 | M01720 | A1 |
| 24 | BAT CHGR | P92 | E1 |
| 24 | BAT/STBY SW POS IND | M01720 | B5 |
| 24 | BATTERY BUS | J9 | A5 |
| 24 | BATTERY CHARGER | J9 | A4 |
| 24 | BUS PWR CONT UNIT | P91 | C10 |
| 24 | BUS TIE BREAKER 1 | P91 | — |
| 24 | BUS TIE BREAKER 2 | P92 | — |
| 24 | CABIN UTIL RLY PWR | P6-11 | A8 |
| 24 | CABIN UTILITY RLY PWR | P6-11 | A8 |
| 24 | DC BUS 1 SECT 1 | P91 | A2 |
| 24 | DC BUS 1 SECT 2 | P91 | C12 |
| 24 | DC BUS 1 XFR | P91 | A1 |
| 24 | DC BUS 2 SECT 1 | P92 | C12 |
| 24 | DC BUS 2 SECT 2 | P92 | A2 |
| 24 | DC BUS 2 XFR | P92 | A1 |
| 24 | DC BUS INDICATION BAT | P6-4 | F14 |
| 24 | DC BUS INDICATION BUS 1 | P6-4 | F16 |
| 24 | DC BUS INDICATION BUS 2 | P6-4 | F18 |
| 24 | DC BUS INDICATION HOT BAT | P6-4 | E15 |
| 24 | DC BUS INDICATION STBY | P6-4 | E18 |
| 24 | DC BUS INDICATION SW HOT BAT | P6-4 | E16 |
| 24 | DUAL BAT RCCB REMOTE | M01720 | A4 |
| 24 | DUAL BATTERY RCCB | J9 | — |
| 24 | ELECTRICAL GND SERV CONT | P6-4 | E13 |
| 24 | ELECTRICAL GND SERV DC 1 | P6-4 | D11 |
| 24 | ELECTRICAL GND SERV DC HOT BAT | P6-4 | E12 |
| 24 | ELECTRICAL TR3 XFR RELAY CONT | P6-4 | E11 |
| 24 | EXT PWR 1 | P92 | A18 |
| 24 | EXT PWR 2 | P92 | A15 |
| 24 | EXT PWR BPCU | P92 | A12 |
| 24 | EXTERNAL POWER CONTRACTOR | P92 | — |
| 24 | GEN 1 LOAD SHED | P91 | C7 |
| 24 | GEN 2 LOAD SHED | P92 | C7 |
| 24 | GENERATOR APU GEN CONT UNIT | P6-4 | F12 |
| 24 | GENERATOR BREAKER 1 | P91 | — |
| 24 | GENERATOR BREAKER 2 | P92 | — |
| 24 | GENERATOR BUS PWR CONT UNIT | P6-4 | F13 |
| 24 | GENERATOR CONT UNIT 1 | P6-4 | F10 |
| 24 | GENERATOR CONT UNIT 2 | P6-4 | F11 |
| 24 | GENERATOR DISC 1 | P6-4 | F8 |
| 24 | GENERATOR DISC 2 | P6-4 | F9 |
| 24 | GND SERV 1 | P91 | A14 |
| 24 | GND SERV 1 | P91 | F1 |
| 24 | GND SERV 1 SECT 1 | P91 | E5 |
| 24 | GND SERV 2 | P92 | A9 |
| 24 | GND SERV 2 | P92 | F1 |
| 24 | HOT BAT BUS | M01720 | B3 |
| 24 | INVERTER REMOTE | M01720 | A5 |
| 24 | INVERTER VOLTS | M01720 | A2 |
| 24 | MAIN BUS 1 | P91 | F6 |
| 24 | MAIN BUS 2 | P92 | F6 |
| 24 | P6 DIST | P92 | C6 |
| 24 | SPCU NORMAL | M01720 | B1 |
| 24 | SPCU STANDBY | M01720 | B2 |
| 24 | STATIC INVERTER RCCB | J9 | — |
| 24 | STBY BUS SECT 1 | M01720 | C1 |
| 24 | STBY BUS SECT 2 | M01720 | C2 |
| 24 | SW HOT BAT BUS | M01720 | B4 |
| 24 | TR3-DC IND | M01720 | C3 |
| 24 | TRU 1 | P91 | A6 |
| 24 | TRU 2 | P92 | A4 |
| 24 | TRU 3 | P92 | A6 |
| 24 | TRU 3 ALTN | P91 | A4 |
| 24 | XFR BUS 1 IFE | P91 | F1 |
| 24 | XFR BUS 1 IFE (INOP) | P91 | F1 |
| 24 | XFR BUS 1 SECT 1 | P91 | F4 |
| 24 | XFR BUS 1 SECT 2 | P91 | F5 |
| 24 | XFR BUS 2 IFE | P92 | F1 |
| 24 | XFR BUS 2 IFE (INOP) | P92 | F1 |
| 24 | XFR BUS 2 SECT 1 | P92 | F4 |
| 24 | XFR BUS 2 SECT 2 | P92 | F5 |
| 25 | 28V DC SERVICE OUTLETS | P6-3 | F1 |
| 25 | EMERGENCY EVAC SIGNAL | P6-3 | C2 |
| 25 | FD -PC POWER | P6-12 | A3 |
| 25 | GALLEY BUS A | P92 | F7 |
| 25 | GALLEY BUS B | P92 | F8 |
| 25 | GALLEY BUS C | P91 | F7 |
| 25 | GALLEY BUS D | P91 | F8 |
| 25 | SERVICE OUTLETS | P92 | E7 |
| 25 | VAC OUTLET AFT | P92 | E9 |
| 25 | VAC OUTLET FWD | P92 | E8 |
| 26 | CARGO FIRE AFT DET A | P18-3 | C19 |
| 26 | CARGO FIRE AFT DET B | P18-3 | C18 |
| 26 | CARGO FIRE EXT 1 | P18-3 | B17 |
| 26 | CARGO FIRE EXT 2 | P18-3 | B16 |
| 26 | CARGO FIRE FWD DET A | P18-3 | C17 |
| 26 | CARGO FIRE FWD DET B | P18-3 | C16 |
| 26 | FIRE PROT DETECTION MA WRN & CONT | P6-2 | A21 |
| 26 | FIRE PROTECTION DET OVHT WW WING BODY | P6-2 | A19 |
| 26 | FIRE PROTECTION DETECTION APU | P6-2 | A23 |
| 26 | FIRE PROTECTION DETECTION ENG 1 | P6-2 | A24 |
| 26 | FIRE PROTECTION DETECTION ENG 2 | P6-2 | A22 |
| 26 | FIRE PROTECTION EXTINGUISHERS ALTN L | P6-2 | B24 |
| 26 | FIRE PROTECTION EXTINGUISHERS ALTN R | P6-2 | B23 |
| 26 | FIRE PROTECTION EXTINGUISHERS APU | P6-2 | B21 |
| 26 | FIRE PROTECTION EXTINGUISHERS LEFT | P6-2 | B22 |
| 26 | FIRE PROTECTION EXTINGUISHERS RIGHT | P6-2 | B20 |
| 26 | LAVATORY SMOKE | P18-3 | E12 |
| 27 | ELEVATOR FEEL LIMIT | P6-2 | C10 |
| 27 | FC TE FLAP POS/SKEW SNSR & IND LEFT | P6-2 | A12 |
| 27 | FC TE FLAP POS/SKEW SNSR & IND RIGHT | P6-2 | A11 |
| 27 | FLIGHT CONT RUDDER AUTHORITY LIMITER | P6-2 | C9 |
| 27 | FLIGHT CONT SHUTOFF VALVES FLT CONT | P6-2 | B13 |
| 27 | FLIGHT CONT SHUTOFF VALVES FLT CONT | P6-2 | C13 |
| 27 | FLIGHT CONT SHUTOFF VALVES STBY RUD | P6-2 | C11 |
| 27 | FLIGHT CONTROL ALTN T.E. FLAP DRIVE | P6-2 | D13 |
| 27 | FLIGHT CONTROL AUTO SPEED BRAKE | P6-2 | B9 |
| 27 | FLIGHT CONTROL AUTOSLAT DC 1 | P6-2 | C14 |
| 27 | FLIGHT CONTROL AUTOSLAT DC 2 | P6-2 | B14 |
| 27 | FLIGHT CONTROL ELEV TAB VLV RIGHT | P6-2 | B8 |
| 27 | FLIGHT CONTROL FLAP LOAD RELIEF | P6-2 | A6 |
| 27 | FLIGHT CONTROL FLAP SHUTOFF VALVES | P6-2 | A7 |
| 27 | FLIGHT CONTROL FSEU DC 1 | P6-2 | A8 |
| 27 | FLIGHT CONTROL FSEU DC 2 | P6-2 | A9 |
| 27 | FLIGHT CONTROL SHUTOFF VALVES SPOILER | P6-2 | B12 |
| 27 | FLIGHT CONTROL STAB TRIM ACTUATOR | P6-2 | D10 |
| 27 | FLIGHT CONTROL STAB TRIM CONT | P6-2 | B10 |
| 27 | FLIGHT CONTROL TRIM CONT AIL | P6-2 | D18 |
| 27 | FLIGHT CONTROL TRIM CONT RUD | P6-2 | D19 |
| 27 | FLIGHT CONTROL TRIM IND RUD | P6-2 | D16 |
| 27 | FORCE FIGHT MONITOR | P6-2 | D15 |
| 27 | SMYD-1 CMPTR DC | P18-2 | E5 |
| 27 | SMYD-1 SNSR EXC AC | P18-2 | E6 |
| 27 | SMYD-2 CMPTR DC | P6-1 | B5 |
| 27 | SMYD-2 SNSR EXC AC | P6-1 | B4 |
| 27 | SPDBRK AUTOSTOW | P6-2 | A10 |
| 27 | SPOILER PCU SOV SYS A | P6-2 | A4 |
| 27 | SPOILER PCU SOV SYS B | P6-2 | A5 |
| 27 | STALL WARN ASYM MODE | P18-2 | E7 |
| 27 | STICK SHAKER LEFT | P18-2 | E4 |
| 27 | STICK SHAKER RIGHT | P6-1 | B6 |
| 28 | AT S-O/UCPO BST PMP CTR TNK L AC | P6-3 | D7 |
| 28 | BOOST PMP CTR TNK L AUTO SHUT OFF-DC | P6-3 | C3 |
| 28 | BOOST PMP CTR TNK R AUTO SHUT OFF-DC | P6-3 | C7 |
| 28 | FUEL AT S-O/UCPO BST PMP CTR TNK R AC | P6-3 | E7 |
| 28 | FUEL BOOST PUMP CTR TANK LEFT | P91 | D5 |
| 28 | FUEL BOOST PUMP CTR TANK LEFT | P91 | D6 |
| 28 | FUEL BOOST PUMP CTR TANK RIGHT | P92 | D5 |
| 28 | FUEL BOOST PUMP CTR TANK RIGHT | P92 | D6 |
| 28 | FUEL BOOST PUMP TANK 1 AFT | P92 | D1 |
| 28 | FUEL BOOST PUMP TANK 1 AFT | P92 | D2 |
| 28 | FUEL BOOST PUMP TANK 1 FWD | P91 | D1 |
| 28 | FUEL BOOST PUMP TANK 1 FWD | P91 | D2 |
| 28 | FUEL BOOST PUMP TANK 2 AFT | P91 | D3 |
| 28 | FUEL BOOST PUMP TANK 2 AFT | P91 | D4 |
| 28 | FUEL BOOST PUMP TANK 2 FWD | P92 | D3 |
| 28 | FUEL BOOST PUMP TANK 2 FWD | P92 | D4 |
| 28 | FUEL CROSS FEED VALVE | P6-3 | B7 |
| 28 | FUEL FUELING CONT | P6-3 | A3 |
| 28 | FUEL FUELING IND | P6-3 | A4 |
| 28 | FUEL QTY 1 | P6-3 | A6 |
| 28 | FUEL QTY 2 | P6-3 | A5 |
| 28 | FUEL SHUTOFF VALVES BUS | P6-3 | C6 |
| 28 | FUEL SHUTOFF VALVES PWR PACK | P6-3 | C4 |
| 28 | FUEL SPAR VALVE ENG 1 | P6-3 | B4 |
| 28 | FUEL SPAR VALVE ENG 2 | P6-3 | B3 |
| 28 | FUEL SPAR VALVE IND | P6-3 | B5 |
| 28 | FUEL TEMP IND | P6-3 | A7 |
| 29 | ELEC HYD PUMP CONTROL SYS A | P92 | C8 |
| 29 | ELEC HYD PUMP CONTROL SYS B | P91 | C8 |
| 29 | ELEC HYD PUMP SYS A | P92 | F3 |
| 29 | ELEC HYD PUMP SYS B | P91 | F3 |
| 29 | HYD SYS ENG PUMP DEPRESS VALVE 1 | P6-2 | B15 |
| 29 | HYD SYS ENG PUMP DEPRESS VALVE 2 | P6-2 | A17 |
| 29 | HYD SYS LDG GR SYS XFR VALVE PRI | P6-2 | C16 |
| 29 | HYD SYS LDG GR SYS XFR VALVE SEC | P6-2 | C15 |
| 29 | HYDRAULIC SYSTEM BRAKE PRESS IND | P6-2 | A13 |
| 29 | HYDRAULIC SYSTEM PTU VALVE CONT 1 | P6-2 | A15 |
| 29 | HYDRAULIC SYSTEM PTU VALVE CONT 2 | P6-2 | A16 |
| 29 | HYDRAULIC SYSTEM SHUTOFF VALVE ENG 1 | P6-2 | C19 |
| 29 | HYDRAULIC SYSTEM SHUTOFF VALVE ENG 2 | P6-2 | C18 |
| 29 | STANDBY HYDRAULIC PUMP | P92 | F2 |
| 30 | ANTI-ICE & RAIN ENG 1 & WING CONT | P18-3 | A6 |
| 30 | ANTI-ICE & RAIN ENG 1 COWL AI VALVE | P18-3 | A7 |
| 30 | ANTI-ICE & RAIN ENG 2 COWL AI VALVE | P18-3 | B7 |
| 30 | ANTI-ICE & RAIN ENGINE 2 CONTROL | P18-3 | B6 |
| 30 | ANTI-ICE & RAIN WING ANTI-ICE VALVE | P18-3 | A1 |
| 30 | ANTI-ICE & RAIN WSHLD WIPER LEFT | P18-3 | B3 |
| 30 | ANTI-ICE & RAIN WSHLD WIPER RIGHT | P18-3 | B1 |
| 30 | HEATERS ALPHA VANE LEFT | P18-3 | C3 |
| 30 | HEATERS ALPHA VANE RIGHT | P18-3 | D3 |
| 30 | HEATERS AUX PITOT | P18-3 | D6 |
| 30 | HEATERS CAPT PITOT | P18-3 | C1 |
| 30 | HEATERS DRAIN | P18-3 | E5 |
| 30 | HEATERS DRAIN MAST AIR | P18-3 | E4 |
| 30 | HEATERS DRAIN MAST GND | P18-3 | E3 |
| 30 | HEATERS ELEV PITOT LEFT | P18-3 | C4 |
| 30 | HEATERS ELEV PITOT RIGHT | P18-3 | D4 |
| 30 | HEATERS F/O PITOT | P18-3 | D5 |
| 30 | HEATERS TEMP PROBE | P18-3 | C2 |
| 30 | HOSE HEATERS | P18-3 | E18 |
| 30 | HOSE HEATERS | P18-3 | F16 |
| 30 | PROBE AUTO HEAT CAPT | P18-3 | D8 |
| 30 | PROBE AUTO HEAT F/O | P18-3 | D9 |
| 30 | PROBE INDICATION CAPT | P6-3 | F18 |
| 30 | PROBE INDICATION F/O | P6-3 | F16 |
| 30 | WASTE/WTR LINE HEATERS | P18-3 | D18 |
| 30 | WINDOW HEAT CONT LEFT FRONT DC | P18-3 | F5 |
| 30 | WINDOW HEAT CONT LEFT SIDE DC | P18-3 | F2 |
| 30 | WINDOW HEAT CONT RIGHT FRONT DC | P18-3 | F1 |
| 30 | WINDOW HEAT CONT RIGHT SIDE DC | P18-3 | F4 |
| 30 | WINDOW HEAT CONTROL LEFT FRONT AC | P18-3 | E1 |
| 30 | WINDOW HEAT CONTROL LEFT SIDE AC | P18-3 | D2 |
| 30 | WINDOW HEAT CONTROL RIGHT FRONT AC | P18-3 | D1 |
| 30 | WINDOW HEAT CONTROL RIGHT SIDE AC | P18-3 | E2 |
| 30 | WINDOW HEAT POWER L4 & L5 | P6-11 | B7 |
| 30 | WINDOW HEAT POWER L4 & L5 (INOP) | P6-11 | B7 |
| 30 | WINDOW HEAT POWER LEFT FRONT | P6-11 | B9 |
| 30 | WINDOW HEAT POWER LEFT SIDE | P6-12 | B9 |
| 30 | WINDOW HEAT POWER R4 & R5 | P6-12 | B7 |
| 30 | WINDOW HEAT POWER R4 & R5 (INOP) | P6-12 | B7 |
| 30 | WINDOW HEAT POWER RIGHT FRONT | P6-12 | B8 |
| 30 | WINDOW HEAT POWER RIGHT SIDE | P6-11 | B8 |
| 31 | ACMS | P6-1 | E4 |
| 31 | DATA LOADER | P18-2 | A9 |
| 31 | DISPLAY CAPT EFIS CONT PANEL | P18-2 | D1 |
| 31 | DISPLAY CAPT INBD | P18-2 | D3 |
| 31 | DISPLAY CAPT OUTBD | P18-2 | D4 |
| 31 | DISPLAY CTR LWR | P6-1 | E12 |
| 31 | DISPLAY CTR UPR | P18-2 | D2 |
| 31 | DISPLAY DEU 1 HOLDUP | P6-1 | D10 |
| 31 | DISPLAY DEU 1 PRI | P18-2 | D5 |
| 31 | DISPLAY DEU 2 HOLDUP | P6-1 | D9 |
| 31 | DISPLAY DEU 2 PRI | P6-1 | D11 |
| 31 | DISPLAY F/O EFIS CONT PANEL | P6-1 | E13 |
| 31 | DISPLAY F/O INBD | P6-1 | E11 |
| 31 | DISPLAY F/O OUTBD | P6-1 | E10 |
| 31 | FLIGHT RECORDER AC | P18-2 | C9 |
| 31 | FLIGHT RECORDER DC | P18-2 | C10 |
| 31 | FLIGHT RECORDER POSITION SENSOR | P18-2 | C8 |
| 31 | LANDING GEAR AURAL WARN | P6-3 | D18 |
| 31 | LANDING GEAR TAKEOFF WARNING CUTOFF | P6-3 | C18 |
| 31 | MASTER CAUTION ANNUNCIATOR BAT | P6-3 | B13 |
| 31 | MASTER CAUTION ANNUNCIATOR BUS 1 | P6-3 | B12 |
| 31 | MASTER CAUTION ANNUNCIATOR CONT 1 | P6-3 | C11 |
| 31 | MASTER CAUTION ANNUNCIATOR CONT 2 | P6-3 | C12 |
| 31 | MASTER CAUTION ANNUNCIATOR CONT 3 | P6-3 | C13 |
| 31 | MASTER CAUTION ANNUNCIATOR CONT 4 | P6-3 | C14 |
| 31 | MISC CLOCK | P6-3 | A2 |
| 31 | MISC CLOCK DISPLAY | P6-3 | A1 |
| 31 | PRINTER | P6-1 | E5 |
| 31 | PRINTER (INOP) | P6-1 | E5 |
| 31 | TAKEOFF WARNING LIGHT | P6-2 | D20 |
| 32 | LANDING GEAR AIR/GND RELAY | P6-3 | D15 |
| 32 | LANDING GEAR AIR/GND SYS 1 | P6-3 | C16 |
| 32 | LANDING GEAR AIR/GND SYS 2 | P6-3 | C15 |
| 32 | LANDING GEAR ALTN EXTEND SOL | P6-3 | D16 |
| 32 | LANDING GEAR ANTISKID INBD | P6-3 | E16 |
| 32 | LANDING GEAR ANTISKID OUTBD | P6-3 | E18 |
| 32 | LANDING GEAR AUTOBRAKE BITE CONT 1 | P6-3 | A18 |
| 32 | LANDING GEAR AUTOBRAKE BITE CONT 2 | P6-3 | A16 |
| 32 | LANDING GEAR BRAKE TEMP MONITOR | P6-3 | E15 |
| 32 | LANDING GEAR LATCH & PRESS WARN | P6-3 | B17 |
| 32 | LANDING GEAR NOSE GEAR STEER | P6-3 | D17 |
| 32 | LANDING GEAR PARKING BRAKE | P6-3 | B16 |
| 32 | PSEU ALTN | P6-3 | D2 |
| 32 | PSEU PRI | P6-3 | D1 |
| 32 | SPSEU POWER 1 | P6-3 | B18 |
| 32 | SPSEU-1 | P6-3 | B18 |
| 32 | TAILSKID | P6-12 | C7 |
| 33 | ACCESS COMPT LT | P91 | C5 |
| 33 | AIR COND COMPT LT | P92 | C3 |
| 33 | BRT ENTRY LTS | P91 | E10 |
| 33 | BRT ENTRY LTS | P91 | E11 |
| 33 | BRT ENTRY LTS (INOP) | P91 | E11 |
| 33 | CABIN EMER LIGHTS | P6-11 | A9 |
| 33 | CARGO COMPT LT-AFT | P92 | C5 |
| 33 | CARGO COMPT LT-FWD | P92 | C4 |
| 33 | CARGO LT CONT | P92 | C10 |
| 33 | CEILING LIGHT AFT-L | P91 | E7 |
| 33 | CEILING LIGHT AFT-L (INOP) | P91 | E7 |
| 33 | CEILING LIGHT AFT-R | P91 | E8 |
| 33 | CEILING LIGHT AFT-R (INOP) | P91 | E8 |
| 33 | CEILING LT-L | P91 | D12 |
| 33 | CEILING LT-L | P91 | E10 |
| 33 | CEILING LT-R | P91 | D11 |
| 33 | CEILING LT-R | P91 | E9 |
| 33 | CONT CABIN LIGHTING PANEL FLOOD CONT | P6-3 | A11 |
| 33 | CONT CABIN LIGHTING PANEL FLOOD STBY | P6-3 | A12 |
| 33 | CONTROL CABIN LIGHTING CONT STAND | P6-3 | A8 |
| 33 | CONTROL CABIN LIGHTING DOME WHITE | P6-3 | A15 |
| 33 | CONTROL CABIN LIGHTING MAP & KIT | P6-3 | A9 |
| 33 | CONTROL CABIN LIGHTING OBS READING | P6-3 | A10 |
| 33 | CONTROL CABIN LIGHTING STBY COMPASS | P6-3 | A14 |
| 33 | COVE LIGHT | P92 | E5 |
| 33 | COVE LIGHT (INOP) | P92 | E5 |
| 33 | ELEC RACK LT-FWD | P91 | C2 |
| 33 | ELEX PANEL LIGHTS AFT CAPT | P8 | — |
| 33 | ELEX PANEL LIGHTS AFT CENTER | P8 | — |
| 33 | ELEX PANEL LIGHTS AFT F/O | P8 | — |
| 33 | ELEX PANEL LIGHTS FWD | P8 | — |
| 33 | EMER PANEL LTG | P6-3 | D8 |
| 33 | ENTRY LIGHTS DIM | P6-4 | E9 |
| 33 | EXT LIGHTING ANTI COLLISION WHITE | P18-3 | B13 |
| 33 | EXT LIGHTING NOSE GEAR TAXI | P18-3 | D14 |
| 33 | EXT LIGHTING RUNWAY TURNOFF RIGHT | P18-3 | C12 |
| 33 | EXTERIOR LIGHTING ANTI COLLISION RED | P18-3 | B12 |
| 33 | EXTERIOR LIGHTING GENERAL LIGHT CONT | P18-3 | D12 |
| 33 | EXTERIOR LIGHTING LANDING LEFT FIXED | P18-3 | B15 |
| 33 | EXTERIOR LIGHTING LANDING LEFT RETR | P18-3 | C15 |
| 33 | EXTERIOR LIGHTING LANDING RIGHT FIXED | P18-3 | C14 |
| 33 | EXTERIOR LIGHTING LANDING RIGHT RETR | P18-3 | B14 |
| 33 | EXTERIOR LIGHTING LOGO ILLUM | P18-3 | A15 |
| 33 | EXTERIOR LIGHTING LTRTL -LEFT | P18-3 | B15 |
| 33 | EXTERIOR LIGHTING LTRTL -RIGHT | P18-3 | B14 |
| 33 | EXTERIOR LIGHTING POSITION LEFT | P18-3 | A13 |
| 33 | EXTERIOR LIGHTING POSITION RIGHT | P18-3 | A12 |
| 33 | EXTERIOR LIGHTING RUNWAY TURNOFF LEFT | P18-3 | C13 |
| 33 | EXTERIOR LIGHTING WING SCAN | P18-3 | A14 |
| 33 | FWD AIRSTAIR TREAD LIGHT | P6-4 | A18 |
| 33 | GALLEY LTS | P92 | E10 |
| 33 | GND SERV CLG NIGHT CONT | P91 | C4 |
| 33 | GND SERV WDO BRT CONT | P92 | C1 |
| 33 | GND SERV WDO BRT CONT (INOP) | P92 | C1 |
| 33 | INDICATOR MASTER DIM BAT | P6-3 | D12 |
| 33 | INDICATOR MASTER DIM BUS 1 | P6-3 | D13 |
| 33 | INDICATOR MASTER DIM BUS 2 | P6-3 | D14 |
| 33 | INDICATOR MASTER DIM DIM/TST CONT | P6-3 | D11 |
| 33 | INDICATOR MASTER DIM SECT 1 | P6-3 | E11 |
| 33 | INDICATOR MASTER DIM SECT 2 | P6-3 | E12 |
| 33 | INDICATOR MASTER DIM SECT 3 | P6-3 | E13 |
| 33 | INDICATOR MASTER DIM SECT 4 | P6-3 | E14 |
| 33 | INDICATOR MASTER DIM SECT 5 | P6-3 | F11 |
| 33 | INDICATOR MASTER DIM SECT 6 | P6-3 | F12 |
| 33 | INDICATOR MASTER DIM SECT 7 | P6-3 | F13 |
| 33 | INDICATOR MASTER DIM SECT 8 | P6-3 | F14 |
| 33 | LAVATORY MIRROR LIGHT | P18-3 | E14 |
| 33 | LAVATORY MIRROR LIGHT | P18-3 | E14 |
| 33 | OVERHEAD 28V PRI | P6-3 | D9 |
| 33 | OVERHEAD 28V SEC | P6-3 | D10 |
| 33 | OVERHEAD 5V SECONDARY | P6-3 | E10 |
| 33 | OVERHEAD 5V SECONDARY | P6-3 | E8 |
| 33 | OVERHEAD 5V SECONDARY | P6-3 | E9 |
| 33 | OVERHEAD 5V SECONDARY | P6-3 | F10 |
| 33 | OVERHEAD 5V SECONDARY | P6-3 | F8 |
| 33 | OVERHEAD 5V SECONDARY | P6-3 | F9 |
| 33 | PANEL & INSTR 28V PRI CAPT & CTR | P6-3 | B9 |
| 33 | PANEL & INSTR 28V PRI F/O | P6-3 | B10 |
| 33 | PANEL & INSTR CB PANEL | P6-3 | C9 |
| 33 | PANEL & INSTR ELEX PANEL | P6-3 | C10 |
| 33 | PASS CAB LT EMER CHGR FLASHLT | P18-3 | B11 |
| 33 | PASS CAB SIGNS LAV OCC SIGN | P18-3 | D10 |
| 33 | PASS CABIN LIGHTING EMER CHGR FWD | P18-3 | A11 |
| 33 | PASS CABIN LIGHTING EMER CHGR L AFT | P18-3 | A10 |
| 33 | PASS CABIN LIGHTING EMER CHGR MID | P18-3 | B9 |
| 33 | PASS CABIN LIGHTING EMER CHGR R AFT | P18-3 | B10 |
| 33 | PASS CABIN SIGNS FASTEN SEAT BELT L | P18-3 | C9 |
| 33 | PASS CABIN SIGNS FASTEN SEAT BELT R | P18-3 | C8 |
| 33 | PASS CABIN SIGNS NO SMOKING LEFT | P18-3 | C11 |
| 33 | PASS CABIN SIGNS NO SMOKING RIGHT | P18-3 | C10 |
| 33 | PASS READING LIGHTS LEFT | P91 | B1 |
| 33 | PASS READING LIGHTS-LEFT | P91 | B2 |
| 33 | PASS READING LIGHTS-LEFT | P91 | B3 |
| 33 | PASS READING LIGHTS-LEFT | P91 | B4 |
| 33 | PASS READING LIGHTS-LEFT | P91 | B5 |
| 33 | PASS READING LIGHTS-LEFT | P91 | B6 |
| 33 | PASS READING LIGHTS-LEFT | P91 | B7 |
| 33 | PASS READING LIGHTS-LEFT | P91 | B8 |
| 33 | PASS READING LIGHTS-LEFT | P91 | B9 |
| 33 | PASS READING LIGHTS-RIGHT | P92 | B2 |
| 33 | PASS READING LIGHTS-RIGHT | P92 | B3 |
| 33 | PASS READING LIGHTS-RIGHT | P92 | B4 |
| 33 | PASS READING LIGHTS-RIGHT | P92 | B5 |
| 33 | PASS READING LIGHTS-RIGHT | P92 | B6 |
| 33 | PASS READING LIGHTS-RIGHT | P92 | B7 |
| 33 | PASS READING LIGHTS-RIGHT | P92 | B8 |
| 33 | PASS READING LIGHTS-RIGHT | P92 | B9 |
| 33 | PASS READING LIGHTS-RIGHT STA 340-464 | P92 | B1 |
| 33 | PASSENGER CABIN PASS CALL LEFT | P18-3 | A8 |
| 33 | PASSENGER CABIN PASS CALL RIGHT | P18-3 | B8 |
| 33 | PASSENGER CABIN SIGNS PASS SIGN CONT | P18-3 | D11 |
| 33 | THRSHOLD LTS | P91 | C1 |
| 33 | THRSHOLD LTS (INOP) | P91 | C1 |
| 33 | THRSHOLD LTS (PROV) | P91 | C1 |
| 33 | WHEEL WELL LT | P92 | C2 |
| 33 | WINDOW LIGHT LEFT | P92 | E12 |
| 33 | WINDOW LIGHT RIGHT | P92 | E11 |
| 33 | WORK AND THSHD LTS | P91 | C3 |
| 34 | ADIRU LEFT AC | P18-1 | E7 |
| 34 | ADIRU LEFT DC | P18-1 | E5 |
| 34 | ADIRU LEFT EXC | P18-2 | E8 |
| 34 | ADIRU RIGHT AC | P6-1 | C14 |
| 34 | ADIRU RIGHT DC | P6-1 | C17 |
| 34 | ADIRU RIGHT EXC | P6-1 | C15 |
| 34 | ATC 1 | P18-1 | B5 |
| 34 | ATC 2 | P6-1 | D14 |
| 34 | ATC ANT SWITCH | P6-1 | E14 |
| 34 | FMCS BITE DC | P18-2 | B10 |
| 34 | FMCS CDU 1 | P18-2 | A7 |
| 34 | FMCS CDU 2 | P6-1 | D15 |
| 34 | FMCS CMPTR 1 | P18-2 | A6 |
| 34 | FMCS CMPTR 2 | P6-1 | D16 |
| 34 | FMCS CMPTR 2 (INOP) | P6-1 | D16 |
| 34 | FMCS MCDU 1 | P18-2 | A7 |
| 34 | FMCS MCDU 2 | P6-1 | D15 |
| 34 | FMCS XFR | P6-1 | E15 |
| 34 | FMCS XFR (INOP) | P6-1 | E15 |
| 34 | GND PROX WARN | P18-1 | B7 |
| 34 | HEAD UP GUIDANCE DEU AC | P18-2 | C3 |
| 34 | HUD ANNUN DC | P18-2 | C1 |
| 34 | HUD CMPTR DC (INOP) | P18-2 | C4 |
| 34 | HUD CONT PNL DC (INOP) | P18-2 | C2 |
| 34 | HUD OHU DC (INOP) | P18-2 | C3 |
| 34 | HUD SYS-ALTN DC | P18-2 | C6 |
| 34 | HUD SYS-NORMAL DC | P18-2 | C5 |
| 34 | INSTR XFR | P18-2 | E2 |
| 34 | ISFD | P18-2 | D8 |
| 34 | MACH WARN SYS -2 | P6-1 | B7 |
| 34 | MACH WARN SYS-1 | P18-2 | E3 |
| 34 | RADIO NAVIGATION ADF 1 | P18-1 | A4 |
| 34 | RADIO NAVIGATION ADF 2 | P6-1 | A17 |
| 34 | RADIO NAVIGATION ADF 2 (INOP) | P6-1 | A17 |
| 34 | RADIO NAVIGATION DME 1 | P18-1 | B3 |
| 34 | RADIO NAVIGATION DME 2 | P6-1 | A14 |
| 34 | RADIO NAVIGATION MMR 1 | P18-1 | A2 |
| 34 | RADIO NAVIGATION MMR 2 | P6-1 | A13 |
| 34 | RADIO NAVIGATION NAV CONT PNL 1 | P18-1 | A3 |
| 34 | RADIO NAVIGATION NAV CONT PNL 2 | P6-1 | A15 |
| 34 | RADIO NAVIGATION NAV SNSR DC-1 | P18-1 | B1 |
| 34 | RADIO NAVIGATION NAV SNSR DC-2 | P6-1 | A10 |
| 34 | RADIO NAVIGATION RADIO ALTM 1 | P18-1 | B4 |
| 34 | RADIO NAVIGATION RADIO ALTM 2 | P6-1 | A16 |
| 34 | RADIO NAVIGATION RMI | P18-1 | A5 |
| 34 | RADIO NAVIGATION VOR 2 | P6-1 | A12 |
| 34 | RADIO NAVIGATION VOR/MKR BCN 1 | P18-1 | A1 |
| 34 | STBY ALTM/ASI VIB | P18-2 | D10 |
| 34 | STBY ATT IND | P18-2 | D9 |
| 34 | TCAS | P18-1 | B6 |
| 34 | TERRAIN DISPLAY | P18-1 | A7 |
| 34 | WEATHER RADAR RT | P6-1 | D13 |
| 35 | OXYGEN IND | P18-3 | F7 |
| 35 | OXYGEN MAN CONT | P18-3 | F8 |
| 35 | OXYGEN PASS LEFT | P18-3 | F10 |
| 35 | OXYGEN PASS RIGHT | P18-3 | F9 |
| 36 | AIR CONDITIONING BLEED AIR PRESS IND | P6-4 | B5 |
| 36 | AIR CONDITIONING BLEED AIR VALVE ISLN | P6-4 | A5 |
| 36 | AIR CONDITIONING BLEED AIR VALVES L | P6-4 | A7 |
| 36 | AIR CONDITIONING BLEED AIR VALVES R | P6-4 | B7 |
| 36 | AIR CONDITIONING BLEED AIR XDCR LEFT | P6-4 | A6 |
| 36 | AIR CONDITIONING BLEED AIR XDCR RIGHT | P6-4 | B6 |
| 38 | GREY WATER DRAIN VALVE | P18-3 | E19 |
| 38 | LAVATORY WATER HEATER A | P18-3 | F13 |
| 38 | LAVATORY WATER HEATER D | P18-3 | F14 |
| 38 | LAVATORY WATER HEATER E | P18-3 | F15 |
| 38 | POT WATER COMPRESSOR | P91 | A18 |
| 38 | POT WATER COMPRESSOR | P91 | D11 |
| 38 | VACUUM WASTE | P18-3 | D19 |
| 38 | VACUUM WASTE BLOWER | P91 | F2 |
| 38 | VACUUM WASTE CONT | P91 | C11 |
| 38 | WATER QTY IND | P91 | C9 |
| 44 | IFE AC (INOP) | P6-1 | B9 |
| 44 | IFE DC (INOP) | P6-1 | B10 |
| 46 | NETWORK FILE SERVER | P6-12 | C1 |
| 46 | NETWORK FILE SERVER (INOP) | P6-12 | C1 |
| 47 | NGS ALT PWR | P18-3 | E15 |
| 47 | NGS ALT PWR (INOP) | P18-3 | E15 |
| 47 | NITROGEN GEN CONT | P18-3 | D17 |
| 47 | NITROGEN GENERATION CONTROL | P18-3 | D17 |
| 47 | NITROGEN GENERATION CONTROL (INOP) | P18-3 | D17 |
| 49 | APU FIRE SW POWER | P6-2 | B19 |
| 49 | APU START CONV | P91 | A11 |
| 49 | AUX POWER UNIT CONT | P6-4 | A14 |
| 49 | AUX POWER UNIT SCU FAN POWER | P6-4 | B14 |
| 49 | AUX POWER UNIT SCU FAN POWER (INOP) | P6-4 | B14 |
| 52 | DOOR LOCK | P6-3 | E1 |
| 52 | FWD AIRSTAIR ACTUATOR | P6-4 | B17 |
| 52 | FWD AIRSTAIR CONT NORMAL | P6-4 | A17 |
| 52 | FWD AIRSTAIR CONT STBY | P6-4 | C16 |
| 52 | FWD AIRSTAIR DOOR | P6-4 | A16 |
| 52 | FWD AIRSTAIR STBY DOOR ACTR | P6-4 | C17 |
| 52 | MID EXIT FLIGHT LOCK L | P6-12 | C8 |
| 52 | MID EXIT FLIGHT LOCK R | P6-12 | C9 |
| 52 | OVERWING FLIGHT LOCK-LEFT | P6-2 | D2 |
| 52 | OVERWING FLIGHT LOCK-RIGHT | P6-2 | D1 |
| 52 | SPSEU POWER 2 | P6-3 | B15 |
| 73 | ENGINE 1 ALTN PWR CHAN A | P18-2 | A5 |
| 73 | ENGINE 1 ALTN PWR CHAN B | P18-2 | A4 |
| 73 | ENGINE 1 RUN/PWR | P18-2 | B3 |
| 73 | ENGINE 2 ALTN PWR CHAN A | P6-2 | D8 |
| 73 | ENGINE 2 ALTN PWR CHAN B | P6-2 | D7 |
| 73 | ENGINE 2 RUN/PWR | P6-2 | B5 |
| 74 | ENGINE 1 IGNITION LEFT | P18-2 | A3 |
| 74 | ENGINE 1 IGNITION RIGHT | P18-2 | A1 |
| 74 | ENGINE 2 IGNITION LEFT | P6-2 | D6 |
| 74 | ENGINE 2 IGNITION RIGHT | P6-2 | D4 |
| 76 | ENGINE 1 START LEVER CHAN A | P18-2 | B1 |
| 76 | ENGINE 1 START LEVER CHAN B | P18-2 | B2 |
| 76 | ENGINE 2 START LEVER CHAN A | P6-2 | B6 |
| 76 | ENGINE 2 START LEVER CHAN B | P6-2 | B7 |
| 76 | ENGINE FUEL ENGINE 1 HPSOV CONT | P6-3 | E5 |
| 76 | ENGINE FUEL ENGINE 1 HPSOV IND | P6-3 | E6 |
| 76 | ENGINE FUEL ENGINE 2 HPSOV CONT | P6-3 | E3 |
| 76 | ENGINE FUEL ENGINE 2 HPSOV IND | P6-3 | E4 |
| 77 | ENGINE VIB MON | P6-2 | A2 |
| 78 | ENGINE 1 THRUST REVERSER CONT | P18-2 | B5 |
| 78 | ENGINE 1 THRUST REVERSER IND | P18-2 | B4 |
| 78 | ENGINE 1 THRUST REVERSER INTLK | P18-2 | B6 |
| 78 | ENGINE 1 THRUST REVERSER SYNC LOCK | P18-2 | B7 |
| 78 | ENGINE 2 THRUST REVERSER CONT | P6-2 | C7 |
| 78 | ENGINE 2 THRUST REVERSER IND | P6-2 | C8 |
| 78 | ENGINE 2 THRUST REVERSER INTLK | P6-2 | C6 |
| 78 | ENGINE 2 THRUST REVERSER SYNC LOCK | P6-2 | C5 |
| 80 | ENGINE 1 START VALVE | P18-2 | B8 |
| 80 | ENGINE 2 START VALVE | P6-2 | C4 |
737NG-FTD-49-24001
737MAX-FTD-49-19001
一、简述
737NG运营人报告了在地面开始问题的APU经验，类似于737MAX-FTD-49-19001中提到的。这些APU地面无启动事件通常包括维护消息（MM）49-41012 NO APU ROTATION SHUTDOWN。地面无启动问题间歇性发生，通常在潮湿位置着陆后或在与当天第一次航班相关的寒冷天气条件下尝试启动。运营人报告称，当这些事件发生时，使用MEL 49-01保留放行，当几天后关闭MEL时，APU会再次启动正常。
二、状态
波音公司使用737 NG和737 MAX飞机健康监测（AHM）APU启动/停止报告，分析737 NG与737 MAX相比的主题问题的范围。这些报告发现，737 MAX-FTD-49-19001中描述的启动问题，737 MAX是737NG的2.4倍。这与受影响运营商的报告一致，他们只看到737 MAX飞机的问题。因此调查聚焦于737 MAX及其与737 NG的差异上。由于737NG与MAX使用相同霍尼韦尔131-9B APU，调查中的一些发现也适用于737NG。
三、临时措施
对于维护信息49-41012，请使用FIM 49-40 TASK 803。此外，波音公司提供以下一般APU启动建议。
1.APU参考MEL保留放行之前，完成3个APU启动尝试，前提是遵循APU启动任务周期限制（参考AMM 49-11-00-860-023）。
2.飞机维修手册（AMM）12-33-02包括极端寒冷天气下运行的服务建议。
•对于温度低于32°F（0°C）的寒冷天气停放，AMM子任务12-33-02-550-016建议拆除主电池和辅助电池，并将电池置于温度保持在50°F（10°C）以上的温暖位置。电池可以留在飞机上，无人看护，最低至5°F（-15°C）。
•为了在32°F（0°C）以下的寒冷天气停放后使飞机恢复运行，AMM TASK 12-33-02-880-006建议如温度低于-35°F（-37°C），需加热APU。
•此外，AMM任务49-11-00-860-801建议在32°F（0°C）以下的寒冷天气或40%以上的湿度下每3天运行一次APU。
3.保持健康的APU和飞机电池，以进一步提高APU在寒冷天气下的启动性能。确保飞机电池充满电。如故障隔离手册（FIM）所述，启动APU时需要22伏或更高电压。满载28伏飞机电池将提供更好的启动能力。请参阅FIM 49-45 TASK 801，了解电池电压小于22伏时的故障排除建议。
4.检查APU排水管是否堵塞，确保其干净，且APU入口管道和入口增压室无障碍物。堵塞的APU入口增压室排水管可能导致无法排水的APU增压室内积水。压缩机部分的多余水分可能在飞行过程中冻结并锁定转子，从而防止着陆后开始，然后随后熔化，释放转子并允许正常运行。
5.在APU启动前，当飞机在地面停放时间过长，可能累积冰雪时，确保APU入口门和APU入口在APU启动之前没有冰雪。
6.监测问题是否更频繁地发生在具有高APU小时/周期的单个飞机上。冷浸泡的开始问题发生在APU上，时间很长。这可归因于动力部分旋转组的磨损，结合APU齿轮、润滑泵和轴承上的冷润滑油比通常更高的粘度拖拽。
三、解决方案
737 NG和737 MAX飞机健康监测（AHM）APU启动/停止数据的比较确定，APU地面无启动问题MAX比NG高2.4倍。因此，737 MAXSRP-49-0071将关注737 MAX，但一些发现也可能适用于737 NG。
四、运营商的建议
为了进一步了解本问题在737 NG飞机和737 MAX飞机之间的差异，波音公司要求提供以下信息：
通过波音通信系统（BCS）消息向波音公司报告737NG APU无法启动事件，该消息包含附件线路维护清单中的信息。如果无法完整完成线路维护检查表，波音公司要求提供以下详细信息：
1.与APU地面无启动事件相关的故障代码/维护消息列表。
2.飞机识别信息
3.APU地面无启动日期和时间
4.位置（如果着陆后离开和到达机场）和飞行阶段
5.启动尝试次数
6.故障排除/维护行动和调查结果
7.APU的序列号和小时/周期
8.起动器/发电机的序列号和小时/周期
9.启动转换器单元的序列号和小时/周期
10.确认无启动问题是间歇性的还是硬故障
