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A B737-800 inspector reports that during a contract facility 'C' check; a #1 engine required fan blade weight report was signed off as accomplished but was not done.
| Attributes | |
| ACN | 677215 |
| Time | |
| Date | 200511 |
| Local Time Of Day | 0601 To 1200 |
| Place | |
| Locale Reference | airport : zzz.airport |
| State Reference | US |
| Altitude | agl single value : 0 |
| Aircraft 1 | |
| Operator | common carrier : air carrier |
| Make Model Name | B737-800 |
| Operating Under FAR Part | Part 121 |
| Flight Phase | ground : maintenance |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | maintenance : inspector |
| Qualification | technician : airframe technician : powerplant technician : inspection authority |
| ASRS Report | 677215 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | maintenance : technician |
| Events | |
| Anomaly | aircraft equipment problem : critical maintenance problem : improper maintenance maintenance problem : improper documentation non adherence : published procedure non adherence : far |
| Independent Detector | other other : 1 |
| Resolutory Action | none taken : detected after the fact |
| Consequence | other |
| Factors | |
| Maintenance | contributing factor : schedule pressure contributing factor : manuals performance deficiency : scheduled maintenance performance deficiency : non compliance with legal requirements performance deficiency : logbook entry performance deficiency : inspection |
| Supplementary | |
| Problem Areas | Maintenance Human Performance Chart Or Publication Company |
| Primary Problem | Maintenance Human Performance |
Narrative:
While performing a left engine cfm fan blade root inspection job card on a B737-800 during a 'C' check maintenance visit; the computer mapping task; which incorporates sending blade weight/moment data to engineering; was signed for but not accomplished due to an interpretation error of the job card. No fan blades were replaced on the #1 engine during the visit and the fan blade vibration history indicated that the vibration levels of the blades were within customer satisfactory levels. It was erroneously interpreted that a new blade mapping was not required because no blades were replaced. Therefore; no weights or moments were changed. The job card; however; states that during 'C' check level or higher maintenance visits; fan blade mapping is required. The aircraft's #1 engine passed the operator's vibration survey maintenance manual task and no rebalance was required. Making revisions to the job card to give more direct guidance of operator's processes and procedures; when third party maintenance is being performed; would greatly help reduce the likelihood of this error recurring.
Original NASA ASRS Text
Title: A B737-800 INSPECTOR RPTS THAT DURING A CONTRACT FACILITY 'C' CHK; A #1 ENG REQUIRED FAN BLADE WT RPT WAS SIGNED OFF AS ACCOMPLISHED BUT WAS NOT DONE.
Narrative: WHILE PERFORMING A L ENG CFM FAN BLADE ROOT INSPECTION JOB CARD ON A B737-800 DURING A 'C' CHK MAINT VISIT; THE COMPUTER MAPPING TASK; WHICH INCORPORATES SENDING BLADE WT/MOMENT DATA TO ENGINEERING; WAS SIGNED FOR BUT NOT ACCOMPLISHED DUE TO AN INTERP ERROR OF THE JOB CARD. NO FAN BLADES WERE REPLACED ON THE #1 ENG DURING THE VISIT AND THE FAN BLADE VIBRATION HISTORY INDICATED THAT THE VIBRATION LEVELS OF THE BLADES WERE WITHIN CUSTOMER SATISFACTORY LEVELS. IT WAS ERRONEOUSLY INTERPED THAT A NEW BLADE MAPPING WAS NOT REQUIRED BECAUSE NO BLADES WERE REPLACED. THEREFORE; NO WTS OR MOMENTS WERE CHANGED. THE JOB CARD; HOWEVER; STATES THAT DURING 'C' CHK LEVEL OR HIGHER MAINT VISITS; FAN BLADE MAPPING IS REQUIRED. THE ACFT'S #1 ENG PASSED THE OPERATOR'S VIBRATION SURVEY MAINT MANUAL TASK AND NO REBALANCE WAS REQUIRED. MAKING REVISIONS TO THE JOB CARD TO GIVE MORE DIRECT GUIDANCE OF OPERATOR'S PROCESSES AND PROCS; WHEN THIRD PARTY MAINT IS BEING PERFORMED; WOULD GREATLY HELP REDUCE THE LIKELIHOOD OF THIS ERROR RECURRING.
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.