Narrative:

On the morning in question, myself, 2 other mechanics and an inspector (who was assisting with the work) removed, balanced and reinstalled a l-hand aileron. (This was 3 weeks prior to the actual date it was discovered). After installation of the aileron and connecting the trim tab, the inspector looked it over (very quickly) and signed it off and released it for service. The installation of the aileron went through uneventfully. Approximately 3 weeks later, I found out the aircraft was at the line when a pilot found the discrepancy and wrote it up in the log. Maintenance was called and they installed 2 cotter pins in the trim tab which were missing. I believe that the inspector inspecting his own work, also having being sleep deprived, affected his ability to see my error. I believe my training was adequate, but that in my expediency I overlooked the basic line of safety -- the cotter pins. With that said, I did safety wire the trim tab but missed the cotter pins. At this point I cannot absolutely without a doubt say one way or another if the cotter pins were installed with an inspector having looked over it.

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Original NASA ASRS Text

Title: A BEECH 1900 WAS DISPATCHED IN NON COMPLIANCE WITH THE R AILERON TRIM TAB COTTER PINS NOT SAFETY WIRED AFTER INSTALLATION.

Narrative: ON THE MORNING IN QUESTION, MYSELF, 2 OTHER MECHS AND AN INSPECTOR (WHO WAS ASSISTING WITH THE WORK) REMOVED, BALANCED AND REINSTALLED A L-HAND AILERON. (THIS WAS 3 WKS PRIOR TO THE ACTUAL DATE IT WAS DISCOVERED). AFTER INSTALLATION OF THE AILERON AND CONNECTING THE TRIM TAB, THE INSPECTOR LOOKED IT OVER (VERY QUICKLY) AND SIGNED IT OFF AND RELEASED IT FOR SVC. THE INSTALLATION OF THE AILERON WENT THROUGH UNEVENTFULLY. APPROX 3 WKS LATER, I FOUND OUT THE ACFT WAS AT THE LINE WHEN A PLT FOUND THE DISCREPANCY AND WROTE IT UP IN THE LOG. MAINT WAS CALLED AND THEY INSTALLED 2 COTTER PINS IN THE TRIM TAB WHICH WERE MISSING. I BELIEVE THAT THE INSPECTOR INSPECTING HIS OWN WORK, ALSO HAVING BEING SLEEP DEPRIVED, AFFECTED HIS ABILITY TO SEE MY ERROR. I BELIEVE MY TRAINING WAS ADEQUATE, BUT THAT IN MY EXPEDIENCY I OVERLOOKED THE BASIC LINE OF SAFETY -- THE COTTER PINS. WITH THAT SAID, I DID SAFETY WIRE THE TRIM TAB BUT MISSED THE COTTER PINS. AT THIS POINT I CANNOT ABSOLUTELY WITHOUT A DOUBT SAY ONE WAY OR ANOTHER IF THE COTTER PINS WERE INSTALLED WITH AN INSPECTOR HAVING LOOKED OVER IT.

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.