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A B737-300 engineering change order to wire a shunt to the left egt circuit at the engine terminal block was done incorrectly.
| Attributes | |
| ACN | 645185 |
| Time | |
| Date | 200501 |
| Local Time Of Day | 1801 To 2400 |
| Place | |
| Locale Reference | airport : zzz.airport |
| State Reference | US |
| Altitude | agl single value : 0 |
| Aircraft 1 | |
| Operator | common carrier : air carrier |
| Make Model Name | B737-300 |
| Operating Under FAR Part | Part 121 |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | maintenance : technician |
| Qualification | technician : powerplant technician : airframe |
| ASRS Report | 645185 |
| 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 : far non adherence : published procedure |
| Independent Detector | other other : 1 |
| Resolutory Action | none taken : detected after the fact |
| Consequence | other other |
| Factors | |
| Maintenance | contributing factor : engineering procedure contributing factor : work cards performance deficiency : non compliance with legal requirements performance deficiency : installation performance deficiency : logbook entry |
| Supplementary | |
| Problem Areas | Chart Or Publication Maintenance Human Performance Aircraft |
| Primary Problem | Chart Or Publication |
Narrative:
On the evening of jan/mon/05; I was assigned to accomplish engineering change order #XXX on aircraft X #1 engine; which required the installation of the egt shunt. Per step #5; the 'connection of the aircraft wiring harness and the wiring harness of the egt shunt of the terminals lugs block on the bracket at a relative position of the engine flange north. Refer to figure 2(south) install the terminal lug of the egt shunt and the aircraft terminals lugs to the studs of the terminal lugs block.' on the evening of jan/tue/05; I conversed with a mechanic who was assigned the same duty only to find out I incorrectly installed the wiring. I installed the egt wire harness and aircraft wiring to the egt shunt. Instead of following the steps correctly; I referred to the figure 2 which doesn't show the aircraft wiring -- only the egt wire harness being repositioned; which contributed to me installing the aircraft wiring incorrectly. Had the figure shown the existence of the aircraft wiring in the old confign along with the new confign; I would have installed the wiring properly per the steps 5 and 5(a) along with figure 2. Upon finding out the proper installation; I immediately informed my supervisor as well as contacting maintenance control informing them of my mistake; which was corrected the morning of jan/wed/05.
Original NASA ASRS Text
Title: A B737-300 ENGINEERING CHANGE ORDER TO WIRE A SHUNT TO THE L EGT CIRCUIT AT THE ENG TERMINAL BLOCK WAS DONE INCORRECTLY.
Narrative: ON THE EVENING OF JAN/MON/05; I WAS ASSIGNED TO ACCOMPLISH ENGINEERING CHANGE ORDER #XXX ON ACFT X #1 ENG; WHICH REQUIRED THE INSTALLATION OF THE EGT SHUNT. PER STEP #5; THE 'CONNECTION OF THE ACFT WIRING HARNESS AND THE WIRING HARNESS OF THE EGT SHUNT OF THE TERMINALS LUGS BLOCK ON THE BRACKET AT A RELATIVE POS OF THE ENG FLANGE N. REFER TO FIGURE 2(S) INSTALL THE TERMINAL LUG OF THE EGT SHUNT AND THE ACFT TERMINALS LUGS TO THE STUDS OF THE TERMINAL LUGS BLOCK.' ON THE EVENING OF JAN/TUE/05; I CONVERSED WITH A MECH WHO WAS ASSIGNED THE SAME DUTY ONLY TO FIND OUT I INCORRECTLY INSTALLED THE WIRING. I INSTALLED THE EGT WIRE HARNESS AND ACFT WIRING TO THE EGT SHUNT. INSTEAD OF FOLLOWING THE STEPS CORRECTLY; I REFERRED TO THE FIGURE 2 WHICH DOESN'T SHOW THE ACFT WIRING -- ONLY THE EGT WIRE HARNESS BEING REPOSITIONED; WHICH CONTRIBUTED TO ME INSTALLING THE ACFT WIRING INCORRECTLY. HAD THE FIGURE SHOWN THE EXISTENCE OF THE ACFT WIRING IN THE OLD CONFIGN ALONG WITH THE NEW CONFIGN; I WOULD HAVE INSTALLED THE WIRING PROPERLY PER THE STEPS 5 AND 5(A) ALONG WITH FIGURE 2. UPON FINDING OUT THE PROPER INSTALLATION; I IMMEDIATELY INFORMED MY SUPVR AS WELL AS CONTACTING MAINT CTL INFORMING THEM OF MY MISTAKE; WHICH WAS CORRECTED THE MORNING OF JAN/WED/05.
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.