A B737-300 was dispatched with the #2 engine fan blade dampers installed improperly causing engine v...

Attributes
ACN	421402
Time
Date	199811
Day	Sun
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : zzz
State Reference	US
Altitude	agl bound lower : 0 agl bound upper : 0
Environment
Light	Daylight
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	B737-300
Navigation In Use	Other Other
Flight Phase	other
Flight Plan	None
Person 1
Affiliation	company : air carrier
Function	other personnel other
Qualification	other other : other
ASRS Report	421402
Person 2
Affiliation	company : air carrier
Function	other personnel other
Qualification	other other : other
Events
Anomaly	aircraft equipment problem : critical non adherence : published procedure non adherence : far other anomaly other
Independent Detector	other other : unspecified
Resolutory Action	none taken : detected after the fact
Consequence	Other
Supplementary
Air Traffic Incident	other

Narrative:

Aircraft xyz. I worked on a job/job card to install fan blades on #2 engine of this aircraft xyz. My part of the job was to check that the fan blade dampers, spacers, retainers and blades were installed correctly. I also installed the rear and front spinner cone. On nov/xz/98 this aircraft developed an engine vibration. The blades were removed and upon removal found all 38 aircraft xyz blade dampers incorrectly installed. My signoff on the job only permitted me to see the front of the blades and dampers as they were all installed with retainers and spacers. I believe to the best of my knowledge that the dampers were installed per the job card in question. Callback conversation with reporter revealed the following information: the reporter states the engine fan retention installation was checked by the reporter after the installation was accomplished by another mechanic. The reporter said the check is made looking at the face of the fan disk and only looking at the end of the parts which would not reveal any incorrect damper installation. The reporter stated the job card to install the dampers has no drawings or visual aids to prevent the incorrect installation but the maintenance manual has clear instructions and good visual aids. The maintenance manual was not used in this case.

Original NASA ASRS Text

Title: A B737-300 WAS DISPATCHED WITH THE #2 ENG FAN BLADE DAMPERS INSTALLED IMPROPERLY CAUSING ENG VIBRATION.

Narrative: ACFT XYZ. I WORKED ON A JOB/JOB CARD TO INSTALL FAN BLADES ON #2 ENG OF THIS ACFT XYZ. MY PART OF THE JOB WAS TO CHK THAT THE FAN BLADE DAMPERS, SPACERS, RETAINERS AND BLADES WERE INSTALLED CORRECTLY. I ALSO INSTALLED THE REAR AND FRONT SPINNER CONE. ON NOV/XZ/98 THIS ACFT DEVELOPED AN ENG VIBRATION. THE BLADES WERE REMOVED AND UPON REMOVAL FOUND ALL 38 ACFT XYZ BLADE DAMPERS INCORRECTLY INSTALLED. MY SIGNOFF ON THE JOB ONLY PERMITTED ME TO SEE THE FRONT OF THE BLADES AND DAMPERS AS THEY WERE ALL INSTALLED WITH RETAINERS AND SPACERS. I BELIEVE TO THE BEST OF MY KNOWLEDGE THAT THE DAMPERS WERE INSTALLED PER THE JOB CARD IN QUESTION. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATES THE ENG FAN RETENTION INSTALLATION WAS CHECKED BY THE RPTR AFTER THE INSTALLATION WAS ACCOMPLISHED BY ANOTHER MECH. THE RPTR SAID THE CHECK IS MADE LOOKING AT THE FACE OF THE FAN DISK AND ONLY LOOKING AT THE END OF THE PARTS WHICH WOULD NOT REVEAL ANY INCORRECT DAMPER INSTALLATION. THE RPTR STATED THE JOB CARD TO INSTALL THE DAMPERS HAS NO DRAWINGS OR VISUAL AIDS TO PREVENT THE INCORRECT INSTALLATION BUT THE MAINT MANUAL HAS CLEAR INSTRUCTIONS AND GOOD VISUAL AIDS. THE MAINT MANUAL WAS NOT USED IN THIS CASE.

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.

A B737-300 was dispatched with the #2 engine fan blade dampers installed improperly causing engine vibration.