Narrative:

Night work was performed on #2 engine of aircraft. The task was the removal and replacement of the #4 generator due to MEL placard and write-up, #4 generator bearing fail message. During the replacement of the generator, the o-ring was improperly installed. Being a new mechanic, (a few months on the job) I was to work with an individual who had performed the task previously. Another mechanic had attained the parts for generator installation. While at the gate, the 2 other mechanics who had done the job previously had gone on to do other jobs inside the airplane while I did most of the generator removal. I believe the generator task was handed down to me due to the foul WX that night, being cold and raining. By the time removal of the failed generator was almost accomplished, the other mechanics were finished with their jobs and were giving me a hand. During installation, all 3 mechanics were present, myself, another mechanic helping the installation of the generator and another mechanic supervising the situation. At no time did I realize there was a problem with the o-ring and apparently no other mechanic had realized the situation. After installation, an operation test was completed by myself and another mechanic who had engine run authority/authorized. We had the lower cowl open during operational tests, then again no problem was detected. The following day, a problem arose with the generator, due to improper installation of the o-ring, which led to the #2 engine being shut down in-flight. The flight was diverted making an emergency landing. I believe all problems could have been dismissed if I had paid closer attention to the removal and installation procedures. I should have checked off all steps as I had performed generator removal and replacement and read again the procedures after I had finished the job, to make absolutely sure that all aspects of the task were covered fully. For not doing this, I have many regrets and hope that others may learn from my mistakes as I have.

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Original NASA ASRS Text

Title: EMB135 CREW WAS REQUIRED TO SHUT DOWN #2 ENG BECAUSE OF AN INCORRECTLY INSTALLED GENERATOR.

Narrative: NIGHT WORK WAS PERFORMED ON #2 ENG OF ACFT. THE TASK WAS THE REMOVAL AND REPLACEMENT OF THE #4 GENERATOR DUE TO MEL PLACARD AND WRITE-UP, #4 GENERATOR BEARING FAIL MESSAGE. DURING THE REPLACEMENT OF THE GENERATOR, THE O-RING WAS IMPROPERLY INSTALLED. BEING A NEW MECH, (A FEW MONTHS ON THE JOB) I WAS TO WORK WITH AN INDIVIDUAL WHO HAD PERFORMED THE TASK PREVIOUSLY. ANOTHER MECH HAD ATTAINED THE PARTS FOR GENERATOR INSTALLATION. WHILE AT THE GATE, THE 2 OTHER MECHS WHO HAD DONE THE JOB PREVIOUSLY HAD GONE ON TO DO OTHER JOBS INSIDE THE AIRPLANE WHILE I DID MOST OF THE GENERATOR REMOVAL. I BELIEVE THE GENERATOR TASK WAS HANDED DOWN TO ME DUE TO THE FOUL WX THAT NIGHT, BEING COLD AND RAINING. BY THE TIME REMOVAL OF THE FAILED GENERATOR WAS ALMOST ACCOMPLISHED, THE OTHER MECHS WERE FINISHED WITH THEIR JOBS AND WERE GIVING ME A HAND. DURING INSTALLATION, ALL 3 MECHS WERE PRESENT, MYSELF, ANOTHER MECH HELPING THE INSTALLATION OF THE GENERATOR AND ANOTHER MECH SUPERVISING THE SIT. AT NO TIME DID I REALIZE THERE WAS A PROB WITH THE O-RING AND APPARENTLY NO OTHER MECH HAD REALIZED THE SIT. AFTER INSTALLATION, AN OP TEST WAS COMPLETED BY MYSELF AND ANOTHER MECH WHO HAD ENG RUN AUTH. WE HAD THE LOWER COWL OPEN DURING OPERATIONAL TESTS, THEN AGAIN NO PROB WAS DETECTED. THE FOLLOWING DAY, A PROB AROSE WITH THE GENERATOR, DUE TO IMPROPER INSTALLATION OF THE O-RING, WHICH LED TO THE #2 ENG BEING SHUT DOWN INFLT. THE FLT WAS DIVERTED MAKING AN EMER LNDG. I BELIEVE ALL PROBS COULD HAVE BEEN DISMISSED IF I HAD PAID CLOSER ATTN TO THE REMOVAL AND INSTALLATION PROCS. I SHOULD HAVE CHKED OFF ALL STEPS AS I HAD PERFORMED GENERATOR REMOVAL AND REPLACEMENT AND READ AGAIN THE PROCS AFTER I HAD FINISHED THE JOB, TO MAKE ABSOLUTELY SURE THAT ALL ASPECTS OF THE TASK WERE COVERED FULLY. FOR NOT DOING THIS, I HAVE MANY REGRETS AND HOPE THAT OTHERS MAY LEARN FROM MY MISTAKES AS I HAVE.

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.