Narrative:

While performing final assembly of B737-300/400 nosewheels, I may have, on 2 occasions, mistakenly installed 2 inboard bearings on these wheels instead of an inboard and outboard bearing. These bearings are very close in size, the inboard bearing having a .125 inch larger inside diameter. One wheel was installed on an aircraft and performed without incident until it was removed for wear. The second wheel discrepancy was detected by a mechanic before installation and corrected. I have performed final assembly (visual check, bearing and seal installation) on excess of 10000 wheels in the past 2 1/2 yrs and can only attribute this mistake to the unusually heavy workload we experienced prior to the 2000 holiday season. I am now working with my supervisor and engineering department to develop new methods in the shop to prevent this from occurring again, possibly a go/no-go device we can use at the bench to confirm proper assembly before the wheel is deemed svcable and placed into stock for service on the aircraft.

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Original NASA ASRS Text

Title: 2 B737-300 NOSEWHEEL AND TIRE ASSEMBLIES WERE BUILT UP INCORRECTLY WITH 2 INBOARD WHEEL BEARINGS INSTALLED. SHOULD HAVE 1 INBOARD AND 1 OUTBOARD.

Narrative: WHILE PERFORMING FINAL ASSEMBLY OF B737-300/400 NOSEWHEELS, I MAY HAVE, ON 2 OCCASIONS, MISTAKENLY INSTALLED 2 INBOARD BEARINGS ON THESE WHEELS INSTEAD OF AN INBOARD AND OUTBOARD BEARING. THESE BEARINGS ARE VERY CLOSE IN SIZE, THE INBOARD BEARING HAVING A .125 INCH LARGER INSIDE DIAMETER. ONE WHEEL WAS INSTALLED ON AN ACFT AND PERFORMED WITHOUT INCIDENT UNTIL IT WAS REMOVED FOR WEAR. THE SECOND WHEEL DISCREPANCY WAS DETECTED BY A MECH BEFORE INSTALLATION AND CORRECTED. I HAVE PERFORMED FINAL ASSEMBLY (VISUAL CHK, BEARING AND SEAL INSTALLATION) ON EXCESS OF 10000 WHEELS IN THE PAST 2 1/2 YRS AND CAN ONLY ATTRIBUTE THIS MISTAKE TO THE UNUSUALLY HVY WORKLOAD WE EXPERIENCED PRIOR TO THE 2000 HOLIDAY SEASON. I AM NOW WORKING WITH MY SUPVR AND ENGINEERING DEPT TO DEVELOP NEW METHODS IN THE SHOP TO PREVENT THIS FROM OCCURRING AGAIN, POSSIBLY A GO/NO-GO DEVICE WE CAN USE AT THE BENCH TO CONFIRM PROPER ASSEMBLY BEFORE THE WHEEL IS DEEMED SVCABLE AND PLACED INTO STOCK FOR SVC ON THE ACFT.

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.