Narrative:

I was assigned to aircraft XXX that had been taken OTS earlier that day for a report of airframe vibrations. The prior shift mechanics found the left elevator trim tab inboard hinge bushings worn and the hinge fitting's bushings worn and loose in the fitting. They looked up the parts they needed in the ipc and had to order them from stores. When they arrived I checked the part numbers for the correct effectivity. I then installed the new hinge fitting and bushings; accomplished the inspection/check for the tab installation. The aircraft was then taken on a test flight and returned to service. About a week later the aircraft was in a c-chk and the inspector noticed that the tab hinge fitting that I installed was upside down and the bolt and bushing opposite to how it should be. After I was told about the error I rechked the maintenance manual for the installation of the fitting. In the removal of the tab in step 2; the first thing it says is to see component maintenance manual. That's the part I missed. It shows the proper fitting installation. The amm shows the fitting right&right but does not say which side bushings go on. I now see the error I made by not catching the note to go to the component maintenance manual. Supplemental information from acn 743764: I was asked to be bump up inspector on aircraft X that had the elevator side of the inboard tab hinge fitting replaced. I accomplished the rii inspection of the hinge fitting and elevator tab. About a week later I was informed that the fitting was installed upside down which made the installation of the bolt backwards. As the rii inspector I did not reference the pictures of the maintenance manual I only looked at the installation and check out. It all was installed ok. There was no way I would know it was backward without looking at a picture. The hinge was removed on the previous shift.

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Original NASA ASRS Text

Title: A B737-700 ACFT LH ELEVATOR TAB INBOARD HINGE FITTING WAS FOUND INSTALLED UPSIDE DOWN AND BUSHING/BOLT BUILD UP BACKWARDS.

Narrative: I WAS ASSIGNED TO ACFT XXX THAT HAD BEEN TAKEN OTS EARLIER THAT DAY FOR A RPT OF AIRFRAME VIBRATIONS. THE PRIOR SHIFT MECHS FOUND THE L ELEVATOR TRIM TAB INBOARD HINGE BUSHINGS WORN AND THE HINGE FITTING'S BUSHINGS WORN AND LOOSE IN THE FITTING. THEY LOOKED UP THE PARTS THEY NEEDED IN THE IPC AND HAD TO ORDER THEM FROM STORES. WHEN THEY ARRIVED I CHKED THE PART NUMBERS FOR THE CORRECT EFFECTIVITY. I THEN INSTALLED THE NEW HINGE FITTING AND BUSHINGS; ACCOMPLISHED THE INSPECTION/CHK FOR THE TAB INSTALLATION. THE ACFT WAS THEN TAKEN ON A TEST FLT AND RETURNED TO SVC. ABOUT A WK LATER THE ACFT WAS IN A C-CHK AND THE INSPECTOR NOTICED THAT THE TAB HINGE FITTING THAT I INSTALLED WAS UPSIDE DOWN AND THE BOLT AND BUSHING OPPOSITE TO HOW IT SHOULD BE. AFTER I WAS TOLD ABOUT THE ERROR I RECHKED THE MAINT MANUAL FOR THE INSTALLATION OF THE FITTING. IN THE REMOVAL OF THE TAB IN STEP 2; THE FIRST THING IT SAYS IS TO SEE COMPONENT MAINT MANUAL. THAT'S THE PART I MISSED. IT SHOWS THE PROPER FITTING INSTALLATION. THE AMM SHOWS THE FITTING R&R BUT DOES NOT SAY WHICH SIDE BUSHINGS GO ON. I NOW SEE THE ERROR I MADE BY NOT CATCHING THE NOTE TO GO TO THE COMPONENT MAINT MANUAL. SUPPLEMENTAL INFO FROM ACN 743764: I WAS ASKED TO BE BUMP UP INSPECTOR ON ACFT X THAT HAD THE ELEVATOR SIDE OF THE INBOARD TAB HINGE FITTING REPLACED. I ACCOMPLISHED THE RII INSPECTION OF THE HINGE FITTING AND ELEVATOR TAB. ABOUT A WK LATER I WAS INFORMED THAT THE FITTING WAS INSTALLED UPSIDE DOWN WHICH MADE THE INSTALLATION OF THE BOLT BACKWARDS. AS THE RII INSPECTOR I DID NOT REF THE PICTURES OF THE MAINT MANUAL I ONLY LOOKED AT THE INSTALLATION AND CHK OUT. IT ALL WAS INSTALLED OK. THERE WAS NO WAY I WOULD KNOW IT WAS BACKWARD WITHOUT LOOKING AT A PICTURE. THE HINGE WAS REMOVED ON THE PREVIOUS SHIFT.

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.