Narrative:

Aircraft was in maintenance for a c-chk; 2C-check and a cable inspection. The inspection was coming to the end and 2 mechanics were on the tail installing the leading edges on the horizontal stabilizer. They called me up on the tail to verify that the de-ice lines were hooked up to the boots. I watched them hook up the lines and then I left to do some paperwork for the next shift. When the 2 mechanics were done installing the leading edges on the horizontal stabilizer I went back up on the tail to verify that all the screws were installed on the leading edge and were tight per the inspection card I was signing off for the 2C-check card X and Y. Items 3 and 5 all the screws were flush and tight. They also replaced the boots on the horizontal stabilizer so I also signed off block 8 and 9 on the required inspection item card for the de-ice boot replacement which de-ice line hookup and leading edge is installed and all screws were installed and tight. Then on 12/tue/05; I was called at my home by my chief inspector to come in early that there was a problem with the aircraft. The leading edges on the horizontal stabilizer were installed on the wrong side left on the right and right on the left and that there was going to be a review board; I was written up for it with a counseling statement. I never thought about looking at the leading edges to see if they were installed on the wrong side because I was always told that it can not be done because the screw holes would not line up and they were all done by hand and not on a jig on each aircraft. I know you can not swap leading edges from plane to plane because we have tried. I always thought the leading edges were idiot proof that you can not put a left on a right or right on the left leading edge; but now I know it can be done. I made a mistake and am sorry for it and it will not happen again to me. Callback conversation with reporter revealed the following information: the reporter stated the incorrect installation was discovered at the terminal prior to flight when a technician observed the vortex generators were on the wrong side of the leading edges. Subsequent checks made on three airplanes with the horizontal leading edges removed revealed all three the leading edges could not be installed incorrectly as the fastener holes would not align. The FAA investigated the incident and were present at the tests.

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Original NASA ASRS Text

Title: AN EMB120 WAS RELEASED FOR SVC WITH THE HORIZ STAB LEADING EDGE INSTALLED INCORRECTLY. L ON R AND R ON L. CORRECTED PRIOR TO FLT.

Narrative: ACFT WAS IN MAINT FOR A C-CHK; 2C-CHK AND A CABLE INSPECTION. THE INSPECTION WAS COMING TO THE END AND 2 MECHS WERE ON THE TAIL INSTALLING THE LEADING EDGES ON THE HORIZ STAB. THEY CALLED ME UP ON THE TAIL TO VERIFY THAT THE DE-ICE LINES WERE HOOKED UP TO THE BOOTS. I WATCHED THEM HOOK UP THE LINES AND THEN I LEFT TO DO SOME PAPERWORK FOR THE NEXT SHIFT. WHEN THE 2 MECHS WERE DONE INSTALLING THE LEADING EDGES ON THE HORIZ STAB I WENT BACK UP ON THE TAIL TO VERIFY THAT ALL THE SCREWS WERE INSTALLED ON THE LEADING EDGE AND WERE TIGHT PER THE INSPECTION CARD I WAS SIGNING OFF FOR THE 2C-CHK CARD X AND Y. ITEMS 3 AND 5 ALL THE SCREWS WERE FLUSH AND TIGHT. THEY ALSO REPLACED THE BOOTS ON THE HORIZ STAB SO I ALSO SIGNED OFF BLOCK 8 AND 9 ON THE REQUIRED INSPECTION ITEM CARD FOR THE DE-ICE BOOT REPLACEMENT WHICH DE-ICE LINE HOOKUP AND LEADING EDGE IS INSTALLED AND ALL SCREWS WERE INSTALLED AND TIGHT. THEN ON 12/TUE/05; I WAS CALLED AT MY HOME BY MY CHIEF INSPECTOR TO COME IN EARLY THAT THERE WAS A PROB WITH THE ACFT. THE LEADING EDGES ON THE HORIZ STAB WERE INSTALLED ON THE WRONG SIDE L ON THE R AND R ON THE L AND THAT THERE WAS GOING TO BE A REVIEW BOARD; I WAS WRITTEN UP FOR IT WITH A COUNSELING STATEMENT. I NEVER THOUGHT ABOUT LOOKING AT THE LEADING EDGES TO SEE IF THEY WERE INSTALLED ON THE WRONG SIDE BECAUSE I WAS ALWAYS TOLD THAT IT CAN NOT BE DONE BECAUSE THE SCREW HOLES WOULD NOT LINE UP AND THEY WERE ALL DONE BY HAND AND NOT ON A JIG ON EACH ACFT. I KNOW YOU CAN NOT SWAP LEADING EDGES FROM PLANE TO PLANE BECAUSE WE HAVE TRIED. I ALWAYS THOUGHT THE LEADING EDGES WERE IDIOT PROOF THAT YOU CAN NOT PUT A L ON A R OR R ON THE L LEADING EDGE; BUT NOW I KNOW IT CAN BE DONE. I MADE A MISTAKE AND AM SORRY FOR IT AND IT WILL NOT HAPPEN AGAIN TO ME. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED THE INCORRECT INSTALLATION WAS DISCOVERED AT THE TERMINAL PRIOR TO FLT WHEN A TECHNICIAN OBSERVED THE VORTEX GENERATORS WERE ON THE WRONG SIDE OF THE LEADING EDGES. SUBSEQUENT CHECKS MADE ON THREE AIRPLANES WITH THE HORIZ LEADING EDGES REMOVED REVEALED ALL THREE THE LEADING EDGES COULD NOT BE INSTALLED INCORRECTLY AS THE FASTENER HOLES WOULD NOT ALIGN. THE FAA INVESTIGATED THE INCIDENT AND WERE PRESENT AT THE TESTS.

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.