[54吊架短舱] SRM学习｜发动机尾喷消音板裂纹放行标准及裂纹扩展处理

Service Request ID:  3-4864443734SUBJECT: [737NG_54] Inquire on the dye penetrant inspection may impact on the soldering repair performance

DESCRIPTION:In The Ref/A/ message, China Southern Airlines (GUN) reported the datum airplane was found with cracking damage at the 11 o'clock location on the acoustic panel of the Right Primary Exhaust assembly. In order to identify the length of cracking, China Southern performed the dye penetration inspection per Ref /B/ & /C/. However, during the component shop visit, the vendor (Goodrich in Tianjin) advised such metal should not be inspected by dye penetration method, due to the porous metal (acoustic panel). As the reference, the vendor provided the Ref /D/ SPM to support their statement. To be more specific, the vendor advised the residual penetration liquid may impact on the soldering performance while doing the repair on the crack. Questions from China Southern Airlines (GUN):1/ Whether the dye penetration method is appropriate for the acoustic panel cracking damage? 2/ If Q1 is yes, please instruct China Southern how to remove the residual penetration liquid prior to the repair. 3/ If Q1 is negative, please advise the appropriate method to determine the length of cracking on the acoustic panel.RESPONSE:Boeing has reviewed Ref/A/ message and recommends China Southern Airlines (GUN) to perform a detailed visual inspection using 30X or greater magnification to determine full extent of crack on the Exhaust Nozzle perforated skin. Refer to SRM 51-10-04, GENERAL, please report any disbonds. Note: Dye penetration method is not recommended within the acoustic panel.

需要提供的数据。

1. Airplane Flight Hours and Cycles.

2. Primary Nozzle Part Number and Series Number.

3. Damage Location – airplane level, engine level and part level.

4. Detail damage size – Crack ending, original crack length, crack length over the stop drill, distance to other adjacent parts / components.

5. Your spanferred disposition, example: stop drill again with repeat inspection?

6. The next flight information.

正文描述（SR3-5067220288）。

DESCRIPTION:China Southern reported a crack damage on perforated skin on Ref/A/ Assy. The crack was originally found on Feb 21 and has been address by stop drill per SRM 54-40-02 Allowable Damage 3.China Southern was carrying out the daily repeat inspection on the crack. On July 27th, China Southern observed the crack was extended the original stop drill. Per the guidance in SRM 54-40-02, Boeing should be contacted for further disposition. The crack located on the No.2 Engine primary exhaust nozzle perforated skin at 12 o'clock area - Zone 2 in SRM 54-40-02 Allowable Damage 3. There is no other damage nearby. Please see attached figure for detail crack dimension. Due to lack of repair capability in Nanning, China Southern is not able to carry out the weld repair in CMM 78-11-37. Thus, they proposed following temporary repair plan for this crack: 1. Due to Dye penetration method is not recommended within the acoustic panel, China Southern Airlines will perform a detailed visual inspection using 30X or greater magnification to determine full extent of crack on the Exhaust Nozzle perforated skin. (per Ref/B/ SR)2. Strop drill the extended crack with 0.125" hole. 3. Continue daily inspection on the damage for crack extension. 4. Carry out the permanent repair within 50 flight cycles. REQUIRED ACTION:1. Please kindly advise if China Southern's proposal is acceptable or not. 2. If no, please further advise if a 1.5-hour ferry flight from Nanning to Guangzhou is acceptable. Your kind response within 12 hours will be highly apspanciated.