螺钉松动导致脚蹬无法踩到底

国内某航司发现在他们的737-800机队中,有几架飞机的脚蹬如下区域螺钉出现松动,导致脚蹬不能踩到底。

于是他们对机队做了些普查,共发现2架飞机有问题,一架有一颗螺钉丢失,另一架有一颗螺钉松动凸起。

 把情况报给波音,波音做了调查,但没有发现普遍性问题。波音认为松动的原因有两个,第一是因为组装时有部件缺件,安装顺序相反了,导致检查视线和操作空间受限;第二是工作人员是借调的,对安装工作不熟悉。采取的改进措施就是将此情况告知厂商和质量,确保安装到位,相关SR3-4313973180。

对于客户,可以定期检查螺钉有无松动,缺失,检查螺钉力矩(34-36磅英寸),还可以在螺钉头涂一层油漆,以方便检查螺钉是否松动转动。另外,将松动的案例和波音的措施告知工作者,也可以减少安装出现错误的可能。螺钉参考件号BACS12ER3K8。

改编自我爱修飞机公众号文章

737脚蹬调节钢索断裂

2022年1月,机队首例737脚蹬调节钢索断裂的案例,为早期引进的5*82飞机。机龄为60012FH和35727CY,钢索件号30-1565,断裂位置如下图所示,接近于下部CRANK INSTL的位置。从断头看,内部偏黑,时间较长,外层较新,为瞬断痕迹。与波音做了沟通,SR 4-5331125010。波音表示审查了BCS数据库,发现极少有关于方向舵踏板调整钢索故障的报告,其中一些报告的位置与本案的位置相似。钢索的断裂是由疲劳引起的。电缆在距离后端约5.5英寸处断裂,这和钢索头出来后向右弯曲点是存在一致性的。该钢索没有MPD检查项目或操作测试。是因为飞行机组在飞行前调整舵踏板时,经常使用舵踏板调整。此时,机组人员应注意任何异常情况。

补充与调节钢索相关的一个737-SL-27-185-A,737NG线号在16 到1690之间的飞机,安装的钢索钢索转轴件号为30-1565-3,这个钢索长度为92INCH,与767通用。在使用到737NG飞机后,有部分飞机反应过转动力偏大的情况。波音在线号1691之后的飞机使用了96INCH长度的钢索转轴,件号为30-1565。波音在工厂的试验表示使用加长的钢索转轴后,操作上更顺滑了一些,建议如果在实际运行中,有机组反应存在操作困难的时候,可以核实钢索转轴件号,如为30-1565-3,可以考虑进行替换。

同时波音提出,不是所有的操作力大都是由于钢索转轴导致的,尤其是在最前和最后的极限位置的时候。

工时方面,波音给出了更换转轴钢索需要30工时。

737大翼封严的损伤标准

2022年1月机队出现运行中克鲁格襟翼损伤的问题,一线提出了标准判定的问题,此前和波音做过沟通,SR3-5126464525。对于损伤原因损坏,波音认为与活动部件相关的正常磨损项目、飞行过程中的正常振动或运动以及基于飞行控制校装的异常磨损。

对于标准,波音提出的标准如下。

In general, if any portion or length of a typical non-metallic bulb or blade seal is damaged (worn, split, frayed) and installed (not missing) and the seal is still performing its intended function, there is no requirement to apply the CDL (if available) or replace the seal. If the seal length is altered (a portion removed), the configuration has been changed and an appropriate CDL should be applied (if available) or the seal should be replaced. We would review repairs on a case-by-case basis. As there are no damage tolerances published in the AMM, HNA could consider defining or categorizing seal damage ‘in-house’ to clarify if such a seal is meeting its intended function. Damage could be categorized in the following fashion:

Category 1: Damage that affects only the surface of the seal without penetrating the outer cloth. This damage can be left as is permanently. This damage does not affect the functionality of the seal. The CDL would not apply.

Category 2: Damage that is up to .25″ wide by 1 inch in length that does not fully penetrate the seal wall can be left as is until the next C-Check. This damage does not affect the functionality of the seal. The CDL would not apply.

Category 3: Damage that is up to .25″ wide by 2 inches in length that does not fully penetrate the seal wall can be left as is until the next A-Check. Regular inspections should be performed at intervals of 10 to 20 Flight Cycles to ensure that the seal does not become fully penetrated or exceed the given criteria.

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