1、 Public Lessons Learned Entry: 3221Lesson Info:a71 Lesson Number: 3221 a71 Lesson Date: 2010-05-20 a71 Submitting Organization: KSC a71 Submitted by: Annette Pitt Subject: Location of Hydraulic Check Valve Prevented Leak Testing of Flex hose Using Ground Pumping Unit GSE Abstract: The location of th
2、e check valve in the hydraulic filter module of the Ground Pumping Unit prevented ground supply pressure to be applied the supply flex hose. The location of the check valve should have been designed to provide leak testing of the supply hose using the ground pumping unit. In the future, consider rem
3、oval and replacement of line replacement units (LRUs) when locating check valves in flight fluid systems. Description of Driving Event: Location of the check valve in the hydraulic filter module prevented ground supply pressure being applied to supply flex hose. This supply flex hose is between the
4、filter module and the hydraulic main pump outlet. The intent of the check valve is to prevent spinning the pump during ground hydraulic testing using ground support equipment (GSE). Lesson(s) Learned: The location of check valve should have been designed to provide leak testing of the supply hose us
5、ing the ground pumping unit. Eventually (per MCR 19092) the check valve was relocated to the “other“ end of the supply hose at the main pump outlet. Recommendation(s): Consider ground testing due to removal and replacement of line replacement units (LRUs) when including and locating check valves in
6、flight fluid systems. Evidence of Recurrence Control Effectiveness: The hydraulic systems in the Space Shuttle were modified by relocating the check valve to the other end of the hydraulic pump flex hose, thereby allowing replacement hoses to be checked at flight pressures without running the auxili
7、ary power unit (APU). Documents Related to Lesson: Master Change Record (MCR) 19092 Move Hydraulic Supply Check Valve To Main Pump Click here to download communication document. Mission Directorate(s): a71 Space Operations Additional Key Phrase(s): a71 1.Entry Systems a71 1.Engineering design and project processes and standards Additional Info: a71 Project: Space Shuttle Program Approval Info: a71 Approval Date: 2010-10-08 a71 Approval Name: mbell a71 Approval Organization: HQ Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
