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日期: 2023 年 2 月 24 日

737MAX执行737-SL-21-147纠正措施时的问题

外部案例

有客户在执行SL 737-SL-21-147时发现管路干扰。建议的维护措施已用尽，但仍无法解决问题。更换较长的紧固件似乎是唯一的选择。波音公司认为，使用螺钉和垫片作为永久性维修是可以接受的。波音公司还确认，可以使用更长的螺钉/垫片来防后续飞机上的纠正。

Question:

Customer found tube interference when performing SL 737-SL-21-147. Recommended maintenance dispositions were exhausted but still could not solve the issue. Replacing by longer fasteners seems to be the only option.

Answer: •Boeing finds it acceptable to use the screws and spacers as a permanent repair. •This response is limited to this Service Request and should not be thought of as a blanket approval for all potential applications or substitutions. • •The repair was considered minor with RDR grant • •Boeing also confirms that the longer screws/spacers can be used to prevent the subject riding condition on future aircraft.

737MAX飞机顶起状态下MFD页面抑制

外部案例

有反应报告说，当飞机在顶起状态处于“空中”状态时。当“在空中”时，客户发现MFD功能被禁用，因此无法进入MFD和工作步骤，客户怀疑在任务之前应该有其他步骤，先使用PSEU并将a/c置于“地面”状态。波音表示MFD维护功能不可进入，当飞机在空中状态时。波音拟对对施工步骤程序做调整，以满足在顶升时，可以执行操作测试。

Question:

“…reported that when a/c on jack and the a/c is “in air”. When “in air”, customer found that the MFD function is inhibited, so they cannot enter MFD, and the work step…, customer suspects there should be other steps before the task, to use PSEU and put a/c “on ground”.”

Answer:

Boeing confirms that the MFD maintenance function is not accessible while the airplane is on jacks due to being “in air” mode.

Boeing advises customer to perform the operational test while not on jacks at this time while Boeing re-evaluates the procedure while on jacks. Boeing will send a follow-on message when an updated procedure for the operational test on jacks is available.

关于为什么一个轮胎压力低于165PSI，需要更换双侧轮胎

SR 4-5728189142

如果轮胎的压力测量值低于165 psig，则如果在过载的情况下滚动，则相邻轮胎发生故障（胎面损失或胎体破裂）的可能性非常高，特别是如果低轮胎在长滑行距离或高速操作（如起飞或着陆）期间处于低压。我们认为唯一可以接受的情况是，如果可以确定飞机没有在高速或长距离低轮胎情况下滚动，则安装相邻轮胎。如果可以保证飞机没有转弯，也没有高速滚动或轮胎气压低的长距离飞行，那么波音公司对不更换轮胎组件和车轴的另一侧没有技术异议。但是，如果怀疑是否满足上述条件，则应谨慎地拆下车轴上的两个轮胎总成。

If pressure of a tire is measured below 165 psig, then the likelihood of the adjacent tire failing (tread loss or carcass rupture) is very high if rolled while overloaded, especially if the low tire was at a low pressure for long taxi distances or during high speed operations such as a takeoffs or landings. The only situation where we would consider it acceptable to leave the adjacent tire installed is if it was known for sure that the airplane did not roll at high speed or for long distances with a low tire.  If it can be assured that the aircraft did not turn, nor rolled at a high speed or for long distances with low tire pressure, then Boeing has No Technical Objection to not replacing the tire assembly and on the other side of the axle.  However, if there is doubt the above conditions are met, it would be prudent to remove both tire assemblies on the axle.

点评：基本上无法有效的进行核实。

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