Narrative:

This is a legible description of the situation with regards to maintenance I was involved with on aircraft xyz heavy check at the air carrier facility at ZZZ airport. On around jan/sun/00 I was assigned paperwork for yaw damper/pressure reducing modification with another technician. Having limited knowledge and recent experience, I chose a section of the modification that involved approximately 6 wires, 2 splices, and a few terminations at various plugs. During the modification I was supposed to pin 2 position on a plug located aft of the cockpit at a disconnect station. The plug in question was marked the same on both sides. Not mirror imaged as should have been. I asked another technician who was familiar with wiring his opinion and we both decided that the 'face' of the plug would be the better choice. I completed the section of the paperwork pertaining to this particular section. I was not assigned the 'ringout' or the testing of the system. On the week of mar/mon/00 the aircraft was being completed from its heavy check and being test flown. After 3 test flts and various 'bite' checks performed, it was determined that the pins had been installed in the wrong position on this plug. Air carrier management started an investigation and determined that I had miswired the plug in question. On apr/mon/00 I was approached by my manager and questioned as to the circumstances.

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Original NASA ASRS Text

Title: A B737-300 DURING A YAW DAMPER MODIFICATION WAS INCORRECTLY WIRED DUE TO CONNECTOR PIN LOCATIONS MANUFACTURED IN ERROR.

Narrative: THIS IS A LEGIBLE DESCRIPTION OF THE SIT WITH REGARDS TO MAINT I WAS INVOLVED WITH ON ACFT XYZ HVY CHK AT THE ACR FACILITY AT ZZZ ARPT. ON AROUND JAN/SUN/00 I WAS ASSIGNED PAPERWORK FOR YAW DAMPER/PRESSURE REDUCING MODIFICATION WITH ANOTHER TECHNICIAN. HAVING LIMITED KNOWLEDGE AND RECENT EXPERIENCE, I CHOSE A SECTION OF THE MODIFICATION THAT INVOLVED APPROX 6 WIRES, 2 SPLICES, AND A FEW TERMINATIONS AT VARIOUS PLUGS. DURING THE MODIFICATION I WAS SUPPOSED TO PIN 2 POS ON A PLUG LOCATED AFT OF THE COCKPIT AT A DISCONNECT STATION. THE PLUG IN QUESTION WAS MARKED THE SAME ON BOTH SIDES. NOT MIRROR IMAGED AS SHOULD HAVE BEEN. I ASKED ANOTHER TECHNICIAN WHO WAS FAMILIAR WITH WIRING HIS OPINION AND WE BOTH DECIDED THAT THE 'FACE' OF THE PLUG WOULD BE THE BETTER CHOICE. I COMPLETED THE SECTION OF THE PAPERWORK PERTAINING TO THIS PARTICULAR SECTION. I WAS NOT ASSIGNED THE 'RINGOUT' OR THE TESTING OF THE SYS. ON THE WK OF MAR/MON/00 THE ACFT WAS BEING COMPLETED FROM ITS HVY CHK AND BEING TEST FLOWN. AFTER 3 TEST FLTS AND VARIOUS 'BITE' CHKS PERFORMED, IT WAS DETERMINED THAT THE PINS HAD BEEN INSTALLED IN THE WRONG POS ON THIS PLUG. ACR MGMNT STARTED AN INVESTIGATION AND DETERMINED THAT I HAD MISWIRED THE PLUG IN QUESTION. ON APR/MON/00 I WAS APCHED BY MY MGR AND QUESTIONED AS TO THE CIRCUMSTANCES.

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.