缩短VSV作动环衬套更换后RTV胶干时间

目前CFM56-7B的VSV作动环衬套更换后使用RTV胶涂抹后,AMM手册给的胶干时间较长,并且一线不熟悉缩短胶干的方法,会造成飞机的长时间停场,经和CFM沟通协调,厂家不同意修订手册加入更多的缩短胶干时间的指导,但是邮件答复了缩短胶干时间的建议方法,具体如下。

厂家答复:

Response: To reduce the 24 hour cure time CFM recommends the following procedure:

1) Concurrent with performance of AMM task as RTV 106 is applied to bushing, apply equal thickness RTV 106 bead to tongue depressor and lay on high pressure compressor case in close proximity to installed bushing. Position quartz lamps under C-duct, directed at VSV lever arm with repaired bushing, positioned 1 to 3 feet away from replaced bushing. Ensure tongue depressor with RTV 106 is in same vicinity of repair bushing.

 a) Following two (2) hours of cure, use a razor knife with tongue depressor to cut through RTV 106 at one end of the bead. If the RTV 106 is cured through to the center it will not be tacky to the touch. If the bead on tongue depressor is cured through to center of cut area, complete the repair and proceed to return aircraft to its usual condition.

 b) If the bead on tongue depressor is NOT cured through to center of cut area, continue to cure aided by quartz lamps an additional 2 hours, then repeat the evaluation per (a) above.

 c) Continue evaluation of the RTV 106 as noted in (a) and (b) above for up to 24 hours since RTV 106 application. After 24 hours since RTV 106 application it is permissible to complete the repair and proceed to return aircraft to its usual condition.

Note: CFM does not have additional guidance on how the variables accelerate the cure time, i.e. lamp wattage or distance. The TDS for RTV 106 (manufactured by Momentive Performance Materials) states “Higher temperatures and humidity will accelerate the cure process. Lower temperature and low humidity will slow the cure rate.” This is why a ‘test specimen’ approach is recommended.   

APU漏油故障导致频繁组件跳开

某航司一架波音73NG,每隔几个月出现一次组件跳开故障,一会左侧,一会右侧,最后排故结果均为ACM转动力矩超限更换,ACM转动力矩标准20磅寸,故障的ACM在翼检查基本在35磅寸左右,且转动不丝滑有间歇性卡滞。

由于间隔时间也不算短,因此刚开始的个别更换没有引起注意,后续进行统计,发现自从APU装机后,2年时间换下了5个ACM,考虑两者存在一定关联度。其中,对最后一次换下的ACM旧件进行了仔细观察,发现本体上残留了少量滑油痕迹。

于是找来了历次更换的ACM修理报告,发现故障原因基本相同,内部有油污。

于是完成了组件排故后,为追寻滑油的来源,对APU引气管隔离检查时,虽然管壁没有明显的滑油痕迹,但是接头处发现了黑色焦炭一类物质,怀疑为滑油经过长期高温烘烤后留下的痕迹。

完成APU更换后,故障未再出现。


APU修理发现问题如下,确实存在APU内部漏油。

附:APU修理报告

驾驶舱灭火瓶卡箍安装方向及调整

根据波音工程图纸及最新改版后的AMM/IPC手册,驾驶舱灭火瓶的固定卡箍起朝向应该向左(向外),以避免意外碰撞导致开锁。

图纸要求:

下图为错误安装的示例:

但目前从库房领出的新件卡箍,初始朝向都是向右的(还可以用在其它位置,向右就无需调整),如下所示:

对此,可以自行调整卡箍朝向,卡环中心安装固定点虽然是铆接的,但仍可施加外力使其绕安装点转动,转动180度使其朝向向左即可。

对此调整卡箍朝向的方法,已经过波音厂家认可:

R1. Per Kidde Aerospace drawing 896698 ID:001 note 2, it states: “BAND TO BE ASSEMBLED UNLATCHED. LATCH ORIENTATION OPTIONAL, LATCH MAY BE ORIENTED TO OPPOSITE SIDE BY ROTATING STRAP AROUND RIVET ATTACHMENT”.

R2. Per the drawing mentioned above, the rivet PN is 304424 (0.187 Eyelet or Semi-Tubular Rivet Cres, Passivated)

R3. Boeing confirms that the bracket part number P/N : 896698 is the same irrespective of latch orientation. The latch (one strap or two straps) orientation is optional for the bracket assembly on the 737NG and 737MAX fleet.

R4. Boeing has No Technical Objection to reposition the band within the bracket assembly in order to orient the latch to left direction on all 737NG and 737MAX.

2025.5.13更新:

波音已将驾驶舱灭火瓶卡箍方向调整改版进IPC,后续将体现在15-AUG-2025的正式手册改版中。

737MAX BLEED灯的一个特殊功能

MAX MEL36-11-03-01B条款中,有如下描述:

此功能描述在SDS中有些语焉不详,且在其它手册中也没有说明:

不过在FCOM中有对此功能有比较清晰的解释:

MAX的BLEED灯除了指示引气跳开外,还可以指示其他一些状况,在这里就起到一种构型提示作用,当飞机执行无引气起飞/复飞时,双发引气电门置于OFF位,且此时在襟翼收上前的45秒时间内不会点亮BLEED灯,以避免干扰机组;襟翼收上后45秒时,此时正常情况下机组应该已完成无引气起飞的构型的恢复操作,所以此时若双发引气电门扔处在OFF位,就会点亮BLEED灯以提醒机组当前构型有问题。同时,在襟翼收上后10分钟后,这时如果再人工关断双发引气,则系统就认为是机组在已知的情况下,人为的有目的关断双发引气,故也不再产生BLEED灯警告。当襟翼放出后此功能会重置,以备复飞时使用无引气时忘记恢复构型。

ENG 2 OIL NOTICE(73M)

项次内容
代码790206
信息分类趋势类
故障等级3
事件分类系统故障
实现构型全机队
关联信息ENG 1/2 OIL LEAK
信息复核需要
复核方式译码或UPLINK
复核要点确认是否需要过站加油
报文解读LEAP-1b发动机部分有高滑耗的问题,当高滑耗造成左右发滑油量有一定差异,需要过站加油,来避免差异进一步增大触发渗漏类报文。
标准处置建议确定为高滑耗引起的需安排过站加油,如果是真实漏油需要参考790201/790202处理
机组操作N/A
信息通告通告发动机工程师
可能性后果延误
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