Narrative:

Aircraft reported #2 engine vibration during approximately 7000 ft. Mechanics reported finding missing blade dampener between #37-38 fan blades. Replaced dampener and vibration checked within limits. I was involved because I signed item 8A for task oriented document requirements of maintenance manual. This task oriented document required me to check that 38 blades and blade components were properly installed. This I did while handing each component to the mechanic that made the actual installation. The engine was run while the aircraft taxied approximately 1 mi from the maintenance hangar to the terminal. No problems were experienced. This maintenance occurred on jun/xa/99, ending approximately XX00. The vibration occurred on jun/xb/99. I can find no information on any other vibration problems during the 2 days of operation. I was informed of the problem 30 days after the event. I do not believe that any part was missing from the fan on jun/xa/99. I was present and actually handed each part to the mechanic who assembled the fan group. No reports of parts were reported after the aircraft left the hangar.

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Original NASA ASRS Text

Title: A B737-300 WAS DISPATCHED IN NON COMPLIANCE WITH 2 BLADE DAMPERS MISSING FROM FAN BLADES ON #2 ENG CAUSING VIBRATION.

Narrative: ACFT RPTED #2 ENG VIBRATION DURING APPROX 7000 FT. MECHS RPTED FINDING MISSING BLADE DAMPENER BTWN #37-38 FAN BLADES. REPLACED DAMPENER AND VIBRATION CHKED WITHIN LIMITS. I WAS INVOLVED BECAUSE I SIGNED ITEM 8A FOR TASK ORIENTED DOCUMENT REQUIREMENTS OF MAINT MANUAL. THIS TASK ORIENTED DOCUMENT REQUIRED ME TO CHK THAT 38 BLADES AND BLADE COMPONENTS WERE PROPERLY INSTALLED. THIS I DID WHILE HANDING EACH COMPONENT TO THE MECH THAT MADE THE ACTUAL INSTALLATION. THE ENG WAS RUN WHILE THE ACFT TAXIED APPROX 1 MI FROM THE MAINT HANGAR TO THE TERMINAL. NO PROBS WERE EXPERIENCED. THIS MAINT OCCURRED ON JUN/XA/99, ENDING APPROX XX00. THE VIBRATION OCCURRED ON JUN/XB/99. I CAN FIND NO INFO ON ANY OTHER VIBRATION PROBS DURING THE 2 DAYS OF OP. I WAS INFORMED OF THE PROB 30 DAYS AFTER THE EVENT. I DO NOT BELIEVE THAT ANY PART WAS MISSING FROM THE FAN ON JUN/XA/99. I WAS PRESENT AND ACTUALLY HANDED EACH PART TO THE MECH WHO ASSEMBLED THE FAN GROUP. NO RPTS OF PARTS WERE RPTED AFTER THE ACFT LEFT THE HANGAR.

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.