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A B737-300 engine displayed excessive vibration on engine change test run caused by the fan blades being incorrectly installed by the engine shop.
| Attributes | |
| ACN | 414764 |
| Time | |
| Date | 199809 |
| Day | Thu |
| Local Time Of Day | 0001 To 0600 |
| Place | |
| Locale Reference | airport : zzz |
| State Reference | US |
| Altitude | agl bound lower : 0 agl bound upper : 0 |
| Environment | |
| Light | Night |
| Aircraft 1 | |
| Operator | common carrier : air carrier |
| Make Model Name | B737-300 |
| Operating Under FAR Part | Part 121 |
| 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 | 414764 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | other personnel other |
| Qualification | other other : other |
| ASRS Report | 414595 |
| Events | |
| Anomaly | aircraft equipment problem : critical non adherence : far non adherence : published procedure |
| Independent Detector | other other : unspecified |
| Resolutory Action | other |
| Consequence | Other |
| Supplementary | |
| Primary Problem | Aircraft |
| Air Traffic Incident | other |
Narrative:
On sep/xa/98 I performed air carrier cfm-56 engine job card #xyz-abc (fan blade lubrication) on engine yxzy with another mechanic. It was reported to me by the company that on engine change run (test) this engine had a vibration. The cause of the vibration was out of sequence blades. Line maintenance removed and reinstalled blades and this corrected the problem and aircraft was returned to service. I remember checking blade sequence on reinstallation of fan blades, but must have inadvertently crossed blades. To correct this situation, I should have rechked blade sequence. Also a better mapping system and blade identify system should be put into the routine job card with a separate sign off block for blade sequencing.
Original NASA ASRS Text
Title: A B737-300 ENG DISPLAYED EXCESSIVE VIBRATION ON ENG CHANGE TEST RUN CAUSED BY THE FAN BLADES BEING INCORRECTLY INSTALLED BY THE ENG SHOP.
Narrative: ON SEP/XA/98 I PERFORMED ACR CFM-56 ENG JOB CARD #XYZ-ABC (FAN BLADE LUBRICATION) ON ENG YXZY WITH ANOTHER MECH. IT WAS RPTED TO ME BY THE COMPANY THAT ON ENG CHANGE RUN (TEST) THIS ENG HAD A VIBRATION. THE CAUSE OF THE VIBRATION WAS OUT OF SEQUENCE BLADES. LINE MAINT REMOVED AND REINSTALLED BLADES AND THIS CORRECTED THE PROB AND ACFT WAS RETURNED TO SVC. I REMEMBER CHKING BLADE SEQUENCE ON REINSTALLATION OF FAN BLADES, BUT MUST HAVE INADVERTENTLY CROSSED BLADES. TO CORRECT THIS SIT, I SHOULD HAVE RECHKED BLADE SEQUENCE. ALSO A BETTER MAPPING SYS AND BLADE IDENT SYS SHOULD BE PUT INTO THE ROUTINE JOB CARD WITH A SEPARATE SIGN OFF BLOCK FOR BLADE SEQUENCING.
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.