LNDG GEAR SHEARS OFF UPON LNDG.

Narrative

THE INST TRAINING FLT WAS DONE IN A CLUB AIRPLANE AND WAS STOPPED AFTER EXPERIENCING PROBS WITH THE TURN COORDINATOR. WE RETURNED TO THE ARPT FOR LNDG. THE STUDENT HAS HIS PVT PLT'S RATING AND IS CURRENT WITH A CURRENT MEDICAL. THE WIND WAS ABOUT 340 DEGS AT 10 KTS AND HE CHOSE TO LAND ON RWY 32. THE PLT LINED UP ON THE RWY WITH ABOUT A 5 DEG CRAB INTO THE WIND. UPON TOUCHDOWN I HEARD A CRUNCHING NOISE FROM THE R LNDG GEAR. THE PLT ADDED PWR AS HE BOUNCED SLIGHTLY; AND UPON TOUCHING DOWN AGAIN; THE R LNDG GEAR COLLAPSED. THE LNDG IN MY OPINION WAS NOT A HARD LNDG AND THE COLLAPSING OF THE GEAR WAS A COMPLETE SURPRISE. THE ACFT SLID ABOUT 700 FT AND CAME TO REST ON THE GRASS BTWN THE RWY AND TAXI AREA. WHILE THE AIRPLANE WAS SLIDING; I SHUT OFF THE FUEL MIXTURE AND ELECTRIC FUEL PUMP AND MAGNETOS; AND INSTRUCTED THE PLT TO SHUT OFF THE FUEL SELECTOR. THE PLT WAS VERY UPSET AND WASN'T ABLE TO SHUT OFF THE SELECTOR. I ALSO OPENED THE DOOR AND UNHOOKED MY SEAT BELT AND INSTRUCTED THE PLT TO DO THE SAME AND TOLD HIM TO EXIT THE PLANE AS SOON AS IT STOPS. WE GOT OUT AND LOOKED DOWN AND THE R GEAR WAS WEDGED UNDER THE R WING. THE NEXT DAY AN A&P MECH INSPECTED THE AIRPLANE AND FOUND CORROSION AT THE ATTACH POINT AND THE TWO OF THE BOLTS HAD PREVIOUSLY BEEN CRACKED HALF WAY THROUGH.