[21空调] ACM故障，控制盒真会有TCV代码！

往下滑查看全文

SR4-3065633570

[737NG_21] Further studying for the Pack fault light

DESCRIPTION:China Southern Guangxi branch experienced the following fault on datum airplane:12/01 - Preflight check, the pilot reported RH PACK light illuminated and he was able to reset the light via Master Caution pushbutton. Mechanic interrogated the #2 Pack/Zone Controller and retrieved the "THIS PACK - TCV" fault light (could not reset on the controller). As a corrective action, mechanic replaced the R Temperature Control Valve and cleared the fault. 12/03 - R PACK light duplicated on spanflight check, and it could not be reset on Master Caution. Further BITE test on #2 Pack/Zone Controller retrieved the "THIS PACK - TCV" fault light again. Post flight check, mechanic replaced the R TCV one more time and cleared the fault per ref /A & B/. 12/05 - Pilot observed the R Pack fault light illuminated on ground and it could not be reset. Further troubleshooting, mechanic noted there was not airflow came out of outlet of R Pack. As such, mechanic replaced ACM (Air Circle Machine). The consequent pack system test was found: 1/ APU bleed air spanssure fluctuated between 20 and 30 psi while dual packs was operating. At the meantime, harsh noise was coming out from A/C bay. China Southern mechanic cleaned the Differential Pressure Sensor of APU Bleed air and they recognized the air spanssure was returned to stable; 2/ While dual packs were operating, no exhaust airflow was coming from outlet of R ram air duct (L side was normal);3/ While single pack was operating, exhaust airflow was coming out from R pack system. At the same time, mechanic observed the deflection of R Flow Control & Shutoff Valve was relatively smaller in comparison with opposite valve. Therefore, mechanic replaced the R Flow Control Valve as final fix. Since then, the fault did not regenerated.China Southern team intends to gain more experiences on this troubleshooting activities, therefore, they requests Boeing to provide additional recommendations in order to assist the future troubleshooting technique.  Note: Due to cumbersome component repair process, China Southern is unable to retrieve the shop repair report at this moment.RESPONSE AND/OR REQUIRED ACTION :China Southern requests Boeing to answer the following questions based on troubleshooting activity report above:1/ Please advise which component is most likely failed part (TCV, ACM or Flow Control Valve) based on fleet experiences.2/ Whether ACM failure or Flow Control Valve failure is able to set the fault light (THIS PACK - TCV) on Pack/Zone Controller? 3/ If Q2 is yes, please provide some insights for the relationship between ACM/FCV versus fault light on Pack/Zone Controller.RESPONSE:Boeing reviewed China Southern's message above and would like to offer the following explanation:The fleet reliability data suggests that the TCV failure is more common and the Flow Control Valve failure is less common.ACM or Flow Control Valve failure should not set the fault light (THIS PACK - TCV) on Pack/Zone Controller.Please advise if further assistance is required.