What was found
(CAN) OUTSIDE BEARING ON #2 MAIN WHEEL ASSEMBLY FAILED AND RESULTED IN WHEEL DEPARTING THE AIRCRAFT. THE BEARING ROLLERS LEFT THE BEARING CAGE ALLOWING THE WHEEL TO EXIT THE AXLE OVER THE SPACER, WASHER AND NUT. INNER BEARING WAS EXCESSIVELY WORN, THERE WAS STILL GREASE IN BEARING. NO SPACER FOUND BETWEEN WHEEL HALVES. AXLE ON DAMAGE ON OPPOSITE WHEEL. INSPECTION PROGRAM BEING IMPLEMENTED FOR INITIAL INSPECTION OF WHEEL BEARINGS, CUPS AND AXLES ON ALL SA226/227 AIRCRAFT.