双发出现X-BLD信息

2023年3月,有飞机反应关车后,双发出现X-BLD信息,自检有73-30712和73-30711信息。表示存在空地信号丢失。

X-BLD message illuminates over Engine N2 indicator during normal operations and when engine start lever is in the IDLE or RUN position.

同时满足以下几个条件,就会触发显示 X-BLD:
1、飞机在空中
2、灭火手柄未拉出
3、启动手柄在 CUTOFF 位
4、N2 转速低于最低风车启动转速(空速/高度条件满足)

在复位DEU、空地、PSEU跳开关,以及整机断电后均无效。

在复位启动手柄跳开关后,该信息消失。

从经验看以上均为可以尝试复位的操作。

关于发动机燃油滤更换后首次启动无燃油

2023年1月有飞机反映燃油滤更换后,从管路内流出的燃油很多。在第一次启发的时候,燃油流量为零,启动失败。后通过湿冷转,启动成功。这里面有两个经验:

1,冷转可以有效进行排气,并使系统保证供油充分。(尝试过打泵,开翼梁活门,然后从油滤放油排气,并没有起到有效的作用)

2,针对更换油滤大量放油后,燃油泵是否存在干磨的情况。GE表示不会。

扩展的看,厂家认为即使翼梁活门没有打开,泵是有油的情况,也不会导致干磨的情况。

波音的看法有所不同,波音建议是更换燃油泵。

针对什么条件下会发生燃油泵的干磨,波音做了以下说明。

The MFP run dry risk is only present if the engine is motored after the fuel is completely drained and the spar valve is not locked open correctly before hand. In all other cases, fuel is at least partially drained. The lack of an associated dry motor protects the pump from extended operation without fuel, as the normal engine start procedure results in fuel introduction to the pump (i.e. spar valve is open) after the start lever switches to idle (~25% N2, relatively soon after the core starts spinning, minimizing any dry rotation of the MFP).

我们的理解是:

燃油滤的更换,与换燃油泵中放油的步骤效果等同,会排掉管路和部件中的燃油。符合FTD的表述,主要是带来空气,影响泵的润滑。

从燃油滤的更换手册可以看出,在最后测试环节,给出了相关提醒,要求开泵和打开翼梁活门,目的也就是给管路和部件补油,但这个提醒对于工作者来说需要转换为实际操作步骤。

从监控开发多年以来,对于换燃油滤后出报文的情况是极少的,对于油滤更换这样一个定期项目来说,表明并不是一个普遍的现象。

基于对提醒项目理解上的问题,与波音做沟通,已建议加注干冷转步骤要求,波音表示提交地面组考虑。

关于MEL73-11-01放行是否需要考虑总压不一致信息

SR 4-5653423749

实际案例中遇到,有飞机启发后出现EEC备用灯亮故障,自检右发EEC有73-31642 ADIRU 1 and ADIRU 2 Total Pressure Data Disagree 信息,针对是否仅需要根据EEC备用灯亮直接MEL放行飞机,还是介于总压信号需核实皮托管,以免产生更严重的空速不一致等异常,存在一定的争议。与波音做了沟通,波音认为在使用MEL之前,运营人实际已经做了故障隔离确认工作,方可使用MEL进行保留放行。

这与此前大家的理解还是存在一定差异的。

Prior to dispatching airplane with appropriate MMEL item’s, MAINTENANCE (M) and OPERATIONS (O) procedures provided in the DDG it is assumed that the operator has already confirmed the failure or abnormal system behavior.  The airplane may then be dispatched by using Boeing suggested DDG (M) and/or (O) procedures or operator defined (M) and/or (O) procedures.  Operators can use Boeing suggested (M) and/or (O) procedures along with additional information which may help in their company MEL, subject to the approval of their local regulatory agency.

It is important to note that the DDG procedures are not intended for troubleshooting. It is the responsibility of the operator to first troubleshoot the nature of the failure before entering the MEL in order to determine whether appropriate MEL dispatch relief can be applied.

In the case of MEL 73-11-11, there are no (M) procedures associated with the MEL item. The MMEL assumes that adequate troubleshooting has been performed prior to applying MMEL dispatch relief. The DDG is not intended to be a troubleshooting document.  Troubleshooting must be performed using the FIM/AMM to isolate the failure, so that the appropriate MMEL dispatch relief may be applied. HNA should troubleshoot any relevant engine and/or indication related messages via AMM/FIM before applying MEL 73-11-11.

Boeing will not revise MEL 73-11-01 to accommodate any relevant engine and/or indication related messages since the DDG assumes that is already done as described above.

件号为2123M63P02(506569-1)的Alternator Stator装机适用性问题

2022你那8月,机队中发现B-14*8右发安装了2123M63P02(506569-1)的Alternator Stator,这个件号在最新版的AMM中新增了一个提醒2123M63P02(506569-1)的Alternator Stator不能安装在7BE发动机上。EMC与厂家核实适用性差异和手册改版原因后,确认如下:

1,件号为2123M63P02(506569-1)的Alternator Stator,厂家没有在CFM56-7BE发动机上取证,该件号不能装在CFM56-7BE发动机,但是在IPC和AMM手册上没有做出限制。

2,波音和CFM发现此问题之后,在最近一版(2022年4月份)的手册修订中修改了AMM手册和IPC适用性。

3,目前手册改版的新要求对于机队的影响,目前查询SAP的装机记录,有3台发动机受影响,安排更换为有适用性的飞机。

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