Narrative:

Mechanics incorrectly installed the #2 engine fan blades in the reverse order that they were removed after accomplishing a fan blade lube during a 'C' check maintenance visit. The routine word card to accomplish this task requires numbering the blades from 1 to 38 in a counterclockwise fashion before removal and reinstallation in the same order and direction as removed. While accomplishing the inspection of the installed blades; I failed to notice that while the blades were correctly ordered; they were installed in a reverse direction (1 to 38 clockwise). I believe the primary factors that contributed to my error were: inattn to detail (comparing work card instructions to actual conditions); assuming that veteran mechanics were beyond the need to scrutinize minute details; allowing myself to become rushed on the job; and fatigue. This particular error could have been avoided by providing a more visual means for ensuring that the blades are correctly installed; i.e.; numbering both the blade and the hub slot where the blade was removed with the same number.

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Original NASA ASRS Text

Title: A B737-300 HAD #2 ENG FAN BLADES REMOVED FOR LUBING. AFTER LUBING; FAN BLADES WERE INSTALLED INCORRECTLY. NUMBERED BLADES WERE TO BE INSTALLED COUNTERCLOCKWISE BUT WERE INSTALLED CLOCKWISE.

Narrative: MECHS INCORRECTLY INSTALLED THE #2 ENG FAN BLADES IN THE REVERSE ORDER THAT THEY WERE REMOVED AFTER ACCOMPLISHING A FAN BLADE LUBE DURING A 'C' CHK MAINT VISIT. THE ROUTINE WORD CARD TO ACCOMPLISH THIS TASK REQUIRES NUMBERING THE BLADES FROM 1 TO 38 IN A COUNTERCLOCKWISE FASHION BEFORE REMOVAL AND REINSTALLATION IN THE SAME ORDER AND DIRECTION AS REMOVED. WHILE ACCOMPLISHING THE INSPECTION OF THE INSTALLED BLADES; I FAILED TO NOTICE THAT WHILE THE BLADES WERE CORRECTLY ORDERED; THEY WERE INSTALLED IN A REVERSE DIRECTION (1 TO 38 CLOCKWISE). I BELIEVE THE PRIMARY FACTORS THAT CONTRIBUTED TO MY ERROR WERE: INATTN TO DETAIL (COMPARING WORK CARD INSTRUCTIONS TO ACTUAL CONDITIONS); ASSUMING THAT VETERAN MECHS WERE BEYOND THE NEED TO SCRUTINIZE MINUTE DETAILS; ALLOWING MYSELF TO BECOME RUSHED ON THE JOB; AND FATIGUE. THIS PARTICULAR ERROR COULD HAVE BEEN AVOIDED BY PROVIDING A MORE VISUAL MEANS FOR ENSURING THAT THE BLADES ARE CORRECTLY INSTALLED; I.E.; NUMBERING BOTH THE BLADE AND THE HUB SLOT WHERE THE BLADE WAS REMOVED WITH THE SAME NUMBER.

Data retrieved from NASA's ASRS site as of January 2009 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.