Narrative:

During the period in sep/03, aircraft experienced several incidents of stalling during descent. After each incident, numerous inspections were performed, and parts were replaced per troubleshooting charts. After a multiple-part replacement and inspection was performed on sep/mon/03, the aircraft was set up for a verification flight on sep/tue/03. It experienced a rejected takeoff due to #2 engine stall. It was subsequently determined that the #7 check valve was not installed on the #2 engine. Records show the engine was recently installed. Engine was converted from a #1 to a #2 engine prior to being installed. During engine change build-up, multiple employee shifts contributed to engine conversion. When engine was completed, step 14 of engine build-up sheet remained blank. This step involves installing the pneumatics package on the engine, but not rigging it, until the engine is on the pylon. Once the pneumatics package is installed, the valve cannot be seen, only a small tab protrudes, indicating valve installation. Since the pneumatics package was already in place, I checked the installation for correct hardware clamps, as well as valve installation, and signed step 14 of the build-up sheet. What can be done to prevent a recurrence of this problem is to ensure engine is left intact after inspection and prior to installation. Secondly, ensure any 'robbed' parts are documented on parts shortage sheet. Third, require a thorough 'pre-installation inspection.'

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Original NASA ASRS Text

Title: AN MD90, ON A TEST FLT FOR CHRONIC R ENG COMPRESSOR STALLING, REJECTED TKOF DUE TO R ENG STALL. FOUND CHK VALVE NOT INSTALLED ON ENG PNEUMATIC PACKAGE.

Narrative: DURING THE PERIOD IN SEP/03, ACFT EXPERIENCED SEVERAL INCIDENTS OF STALLING DURING DSCNT. AFTER EACH INCIDENT, NUMEROUS INSPECTIONS WERE PERFORMED, AND PARTS WERE REPLACED PER TROUBLESHOOTING CHARTS. AFTER A MULTIPLE-PART REPLACEMENT AND INSPECTION WAS PERFORMED ON SEP/MON/03, THE ACFT WAS SET UP FOR A VERIFICATION FLT ON SEP/TUE/03. IT EXPERIENCED A REJECTED TKOF DUE TO #2 ENG STALL. IT WAS SUBSEQUENTLY DETERMINED THAT THE #7 CHK VALVE WAS NOT INSTALLED ON THE #2 ENG. RECORDS SHOW THE ENG WAS RECENTLY INSTALLED. ENG WAS CONVERTED FROM A #1 TO A #2 ENG PRIOR TO BEING INSTALLED. DURING ENG CHANGE BUILD-UP, MULTIPLE EMPLOYEE SHIFTS CONTRIBUTED TO ENG CONVERSION. WHEN ENG WAS COMPLETED, STEP 14 OF ENG BUILD-UP SHEET REMAINED BLANK. THIS STEP INVOLVES INSTALLING THE PNEUMATICS PACKAGE ON THE ENG, BUT NOT RIGGING IT, UNTIL THE ENG IS ON THE PYLON. ONCE THE PNEUMATICS PACKAGE IS INSTALLED, THE VALVE CANNOT BE SEEN, ONLY A SMALL TAB PROTRUDES, INDICATING VALVE INSTALLATION. SINCE THE PNEUMATICS PACKAGE WAS ALREADY IN PLACE, I CHKED THE INSTALLATION FOR CORRECT HARDWARE CLAMPS, AS WELL AS VALVE INSTALLATION, AND SIGNED STEP 14 OF THE BUILD-UP SHEET. WHAT CAN BE DONE TO PREVENT A RECURRENCE OF THIS PROB IS TO ENSURE ENG IS LEFT INTACT AFTER INSPECTION AND PRIOR TO INSTALLATION. SECONDLY, ENSURE ANY 'ROBBED' PARTS ARE DOCUMENTED ON PARTS SHORTAGE SHEET. THIRD, REQUIRE A THOROUGH 'PRE-INSTALLATION INSPECTION.'

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.