Narrative:

On jul/xa/01, I accomplished a 100 hour service on a C172R. I was rushing because I was told the plane was slotted for a flight that night. I don't know if the plane flew. During the service, I installed the left wheel assembly on the axle. I put the cotter pin in through the axle, nut but I failed to put it through the axle. This made the wheel assembly unsecured. The plane flew for a couple of days, and was performing touch-and-goes. The pilot told me he performed 12-15 touch-and-goes. On the last landing, he said he heard a grinding sound. He discovered that the axle nut had backed off completely. The outer bearing came out. The wheel assembly was held in place by the brake caliper. He was ok and the plane too, except for the bearings.

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Original NASA ASRS Text

Title: A C172R ON LNDG LOST THE L MAIN GEAR AXLE NUT AND OUTER BEARING DUE TO INCORRECT INSTALLATION OF AXLE NUT COTTER PIN.

Narrative: ON JUL/XA/01, I ACCOMPLISHED A 100 HR SVC ON A C172R. I WAS RUSHING BECAUSE I WAS TOLD THE PLANE WAS SLOTTED FOR A FLT THAT NIGHT. I DON'T KNOW IF THE PLANE FLEW. DURING THE SVC, I INSTALLED THE L WHEEL ASSEMBLY ON THE AXLE. I PUT THE COTTER PIN IN THROUGH THE AXLE, NUT BUT I FAILED TO PUT IT THROUGH THE AXLE. THIS MADE THE WHEEL ASSEMBLY UNSECURED. THE PLANE FLEW FOR A COUPLE OF DAYS, AND WAS PERFORMING TOUCH-AND-GOES. THE PLT TOLD ME HE PERFORMED 12-15 TOUCH-AND-GOES. ON THE LAST LNDG, HE SAID HE HEARD A GRINDING SOUND. HE DISCOVERED THAT THE AXLE NUT HAD BACKED OFF COMPLETELY. THE OUTER BEARING CAME OUT. THE WHEEL ASSEMBLY WAS HELD IN PLACE BY THE BRAKE CALIPER. HE WAS OK AND THE PLANE TOO, EXCEPT FOR THE BEARINGS.

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.