关于MAX独有的两个EGT超限值说明

SR 3-5611381834

在机组操作手册中,有两个独有的超温是维护手册中所没有的。High Power Fuel Cut和Quick Windmill Relight。特做相关说明。

High Power Fuel Cut 指当燃油切断时,发动机推力杆处于或高于爬升推力功率。

Quick Windmill Relight 风车启动,EEC自动选择,并提高EGT的裕度标准。

The High Power Fuel Cut condition is defined as the engine thrust lever being at or above climb thrust power when the fuel switch is cut-off.
Two methods of starting an engine in flight are available: windmill and crossbleed/Air Starting. The only difference between the Quick Windmill Relight (QWRL) and the standard in-flight start procedure is the allowed EGT limit as you have noted in the AFM. The Electronic Engine Control (EEC) provides automatic selection of the start EGT limit and is able to raise the standard in-flight EGT limit when it recognizes a Quick Windmill Relight start attempt.
Different design and certification requirements on LEAP-1B (737 MAX) and CFM56-7B (737NG) engines lead to different EGT limits.

737MAX的EDP失效导致滑油滤旁通

外部案例

2023年3月23日,一架注册号为C-FQGG的Westjet波音737-8 MAX从安大略省多伦多飞往加拿大卡尔加里执行WS-4201航班,从多伦多起飞后,在FL360高度,机组人员收到了2号发动机(LEAP)EDP低压指示。机组执行检查单,不久后,右发滑油滤旁通灯亮起,机组执行检查单后故障依旧,关闭右发,宣布PAN PAN,并在起飞约90分钟后返回多伦多,在33R跑道上安全着陆。

加拿大TSB报告称,维修发现2号发动机驱动泵和2号发动机吊架之间的液压管路快接头未有效连接,重装管路。该航司做了全机队检查,以验证液压快速断开接头是否全部处于锁定位置。

从现象分析应该为,EDP管路未有效连接,导致EDP出现低压和过热,液压油进入到滑油,导致空停的发生。从波音了解到安装的为EATON构型EDP。该事件符合EATON泵失效模型。(EATON失效详情分析参见EATON构型EDP泵失效导致空停事件)

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