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月度归档： 2022 年 11 月

关于发动机前吊架整流罩盖板封严损伤标准

SR 3-5454271361，HNA-HNA-21-0556，HNA-HNA-23-2381-10B

由于手册没有检查标准，波音当前均采用一事一议的方式。

以下案例的损伤情况，波音提供了RDR做为临时修理方案，保留100CY。（2023年后申请未得到批准）

封严：311A2535-31/311A2535-32/311A2535-33/311A2535-34

吊架整流罩盖板封严检查可以由如下项目涵盖:

1.区域检查MP70-800-01 (T=R=120CA)和70-810-02(T=R=120CA)。JC-73N-70-810/820-02

2. 航后检查工卡QZ-AF。

2023年10月补充案例

Boeing has reviewed the Ref /A/ messae and finds that the proposed time limited repair is NOT acceptable due to the location of the seals. The seal is within the fire zone of the engine per FAR 25.867 and required to be fire resistant.There are no fly on limits for continued revenue fight operations with seal section missinp or damaged. The proposed BMS 5-95 sealant is not acceptable to use in location with temperatures more than 180 degrees F (82 degrees C),Therefore the use of BMS 5-95 with speed tape wil not adequately protect the structure during a fire event.
1、Boeing recommends either the seal be replaced prior to any flight, or as a time-limited repair apply BMS 5-63 sealant to any gap with missing sealI inspect at 500 hour intervals to ensure that the sealant intact, Replace the damaged seal if further deterioration is found during repeat inspection. Boeing Recommends replacing the damaged seal at the next available opportunity, to be no later than 200 flight cles or 30 days time limit.

2、Boemg notes that BM 5-63 can have up to 72 hour cure time howeve, this can not e avoided. Beimg states that the manufacturers cure tim nstrucions for the BMS 5-63 type must be adhered too.

3、To prevent heat damage to the seal in the future and potentialy to the strut fairing panel as well, Boeing recommends checking the AMM 54-52-0 aerodnamic smoothmes recuirements at strut T/R fairing to T/R aft cowl when rigging the T/R.The allowable steps is +.0750 IN to -.1200 IN larger negative steps could result in a gap that allows hot air to vent and can cause damage to the strut faring mpanel.Reter to AMM 78-31-01/501 to adjust the T/R and increase latch pressure as reduired to correct the thrust reverser pap condition.
Our review of the guidelines provided in Boeing Service leter 737-SL-51-041 indicates this repair can be considered minor repair. Enclosed is the Ref / Repair and Devation Record RDR)form that documents acceptance of this repair data.

反推上部盖板431EL、431ER、441EL、441ER的封严受高温（约215F，封严耐450F）和高速气流的影响，在使用后出现损伤。由于SRM手册中并未给出允许损伤的标准。在经历了多次的CASE BY CASE沟通后，分别于2021年4月和2022年11月两次向波音提出机队性的放行标准申请。均被波音以需要符合FAR 25.867防火性要求，需根据每个案例的判断拒绝，建议制定合适的GVI检查间隔来发现。因此结合局方要求，编写了培训教材，并在定期工卡中加入了检查图示。后续延续运行中决策，和单起事件逐个向波音报批的政策，一些不严重的损伤会得到波音临时修复的审批。最初使用BMS5-95加金属胶带，可以作为临时措施并提供RDR。后来改为BMS5-63加金属胶带。

2023年11月更新，HNA-HNA-23-2381-10B 波音认为当损伤的间隙低于0.125英寸，是可以使用BMS 5-63来修理，可以通过加温来加速固化。并按100FC来进行目视检查，500FC完成更换。如果大于了0.125英寸需要更换。

  1. If HNA detect any gap between Pylon Strut Panel and Fairing of Thrust Reverser up to 0.125”, it may be
    repaired with BMS5-63 sealant to completely close this gap. However, if the any detected gap is higher
    than 0.125”, this seal shall be removed and, replaced by a new one.
  2. The BMS5-63 sealant has to be completely cured per BAC5000 requirements.
  3. A Detail Visual Inspection (DVI) shall be done every 100FC as stated in Ref /C/ message.
  4. This procedure is a temporary repair and, the damaged seal shall be replaced in the first opportunity and
    after 500FC per Ref /C/ message.

  1. No large gaps exceeding 0.125 inch wide are allowed in thesteady showed in Ref /C/ message and Red /D/ sketch. f any gap up to 0.125″is detected, this gap shallbe flled with BMS5-63 sealant as a temporary repaiSurface damage made by erosion etc. can be filled with BMS5-63 sealant and properly cured per BAC 5000.2. Corect. Any detected gap shall be flled with BMS5-63 sealant as temporary repair. 500 fight hours (FH) maximum.3.The ss-3 type, cs B-4has ure me f 40 hous Bmn pec BAC5-be xm) eded the ure ofM-3 seant ma be tceleratedhy sg condurcte heat with mamumt temperture of145F ts
    surface
  2. If the gap is greater than 0.125 inch, the damaged seal shabe replaced by a new one. Please note that the area is critical for fire as it is at the enaine exhaust region.5. Boeing recommends a Detail Visual inspection (DVI) at ever100 Flight Hours (FH) and replacement of the seal at a maximum of 500 Flight Hours (FH).

Untitled

标题电源转换时DPC-1或DPC-2干扰状态信息
Nuisance DPC-1 or DPC-2 Status Messages
During Power Transfer
编号737MAX-FTD-31-21002
章节31
适用性737MAX
日期2022年10月
机队影响ALL
是否关闭否
背景DPC在每次飞机通电时会进行时长30s的开机自检，
此自检通过需要主电源和备用电源都正常。如果此自检没有完成，
不可放行的状态信息DPC-1或DPC-2会伴随着MAINT灯亮而一起出现。
在这种情形下，在故障历史里可以看到下述一条或多条维护信息。
31-02921；31-02922；31-00241；31-00242；31-90011；
31-90012；31-00291;31-00292；31-00371；31-00372
波音已确定在飞机没有接外部电源，而APU通过电瓶电
在DPC驱动显示前启动时，也会造成上述干扰故障。
因APU启动会瞬时抽光电瓶的电压，
导致DPC误认为自己在开机自检时失去了一路电源供应。
（在使用外接电时，上述所列故障不会被设定）
波音与柯林斯确信此为干扰故障。涉及的DCPs依然可操作。
只要故障能被清除，DCP也无需被更换。
改进状态波音正与柯林斯一起调查此问题的根本原因。
调查发现通电时存在电压下降导致DPC自检不通过
引起了状态信息DPC-1或DPC-2。
目前波音认为DPC无法通过自检的原因为一下两条之一：
1.电源转换时的低电瓶电压；
2.电源转换操作时序
波音已对相关维护信息的FIM进行了改版，
目前也在对FCOM的通电补充程序进行改版（预计2021年11月完成），
相关SRP也已经设立。
临时措施见附件
最终方案等待波音的最终方案
点评N/A
737MAX-FTD-31-21002-临时措施下载

关于胎压能否突破手册上限的问题

SR 4-5669181453

由于胎压与胎皮使用循环数息息相关，针对能否提高现行胎压标准，与波音做了较多的沟通。最终波音的解释如下：

一是胎压变化影响轮胎与地面接触面，与设计的刹车距离会有差异；

二是轮舱内爆胎的取证压力问题，对其他管路、线路等的影响。基于以上初始适航取证问题，不可以进行随意调整。

因而与轮胎本身额定设计压力会存在一些区别。

Even though Ref /A/ reference guide lists a MLG tire pressure higher than what is required in Ref /B/, Boeing notes that 737-800 is certified to operate only at MLG tire pressures specified in Ref /B/.

Increasing the tire pressure above allowable limits changes the tire footprint on the ground which directly affects its certified stopping distance.  In addition, the airplane wheel well components (cables, pipes, brackets, etc.) were all certified to withstand potential tire burst event at maximum pressure as listed in Ref /B/. Operating MLG tire pressures higher than values specified in Ref /B/ would be deviating from allowable airplane certification limitations and are therefore not authorized.

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