Narrative:

On the night of oct/sun/06; myself and 2 other mechanics and an inspector were working blade lube on #2 engine. The 3 of us mechanics had very little experience with B737-700 blade removal and installation. I had mentioned this to the inspector and ask him to watch us closely. I was in the inlet while the other mechanics cleaned and inspected the blades. After cleaning and inspecting the blades and lubing the banana clips the clips were placed in the box for installation. I was installing the parts as they were handing me the parts. The banana clips were still in the box; apparently out of sight; and I didn't notice they were missing. After the installation was complete I noticed that when I would spin the blade they would stop and make a slight turn in reverse. I knew that wasn't normal and mentioned it to the inspector and my lead. We decided to see how the engine 'vib' run looked. After they ran the engines the 'vib' run was good I also check the blades and the reverse spin had stopped. I assumed the spin was due to heavy lube. The aircraft was returned to service when the 'C' check was completed later that day. The aircraft left ZZZ and flew for the day. The night of oct/mon/06; a mechanic found the box of clips on the blade stand and question why they were still there. The plane was grounded in ZZZ1; the blades were removed and the engine hub was inspected. No damage was found to the hub so the blades were replaced with new and the plane was released for service.

Related reports:

Google
 

Original NASA ASRS Text

Title: A B737-700 WAS DISPATCHED AFTER #2 ENG FAN BLADE LUBRICATION WAS PERFORMED. LATER DISCOVERED FAN BLADE SPACERS WERE NOT INSTALLED.

Narrative: ON THE NIGHT OF OCT/SUN/06; MYSELF AND 2 OTHER MECHS AND AN INSPECTOR WERE WORKING BLADE LUBE ON #2 ENG. THE 3 OF US MECHS HAD VERY LITTLE EXPERIENCE WITH B737-700 BLADE REMOVAL AND INSTALLATION. I HAD MENTIONED THIS TO THE INSPECTOR AND ASK HIM TO WATCH US CLOSELY. I WAS IN THE INLET WHILE THE OTHER MECHS CLEANED AND INSPECTED THE BLADES. AFTER CLEANING AND INSPECTING THE BLADES AND LUBING THE BANANA CLIPS THE CLIPS WERE PLACED IN THE BOX FOR INSTALLATION. I WAS INSTALLING THE PARTS AS THEY WERE HANDING ME THE PARTS. THE BANANA CLIPS WERE STILL IN THE BOX; APPARENTLY OUT OF SIGHT; AND I DIDN'T NOTICE THEY WERE MISSING. AFTER THE INSTALLATION WAS COMPLETE I NOTICED THAT WHEN I WOULD SPIN THE BLADE THEY WOULD STOP AND MAKE A SLIGHT TURN IN REVERSE. I KNEW THAT WASN'T NORMAL AND MENTIONED IT TO THE INSPECTOR AND MY LEAD. WE DECIDED TO SEE HOW THE ENG 'VIB' RUN LOOKED. AFTER THEY RAN THE ENGS THE 'VIB' RUN WAS GOOD I ALSO CHK THE BLADES AND THE REVERSE SPIN HAD STOPPED. I ASSUMED THE SPIN WAS DUE TO HVY LUBE. THE ACFT WAS RETURNED TO SVC WHEN THE 'C' CHK WAS COMPLETED LATER THAT DAY. THE ACFT LEFT ZZZ AND FLEW FOR THE DAY. THE NIGHT OF OCT/MON/06; A MECH FOUND THE BOX OF CLIPS ON THE BLADE STAND AND QUESTION WHY THEY WERE STILL THERE. THE PLANE WAS GNDED IN ZZZ1; THE BLADES WERE REMOVED AND THE ENG HUB WAS INSPECTED. NO DAMAGE WAS FOUND TO THE HUB SO THE BLADES WERE REPLACED WITH NEW AND THE PLANE WAS RELEASED FOR SVC.

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.