As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PRIOR TO TAKEOFF, MGB CHIP LIGHT ILLUMINATED. INSPECTED CHIP DETECTOR AND FILTER ELEMENT, FINDINGS CLASSIFIED AS STAGE "B" DEPOSITS IAW SECTION 3, PART 3, FIG 5. REPLACED OIL FILTER AND CLEANED CHIP PLUG. PERFORMED 15 MIN GROUND RUN WITH NO DEFECTS NOTED. CHIP EVENT REQUIRED A TOOTHING INSPECTION IAW ASB EC135-63A-012 WITHIN 10 HOURS. INSPECTED MGB INPUT GEARSETS IAW ASB EC135-63A-012. FOUND PITTING DAMAGE ON SEVERAL TEETH ON NR 2 SIDE INPUT PINION PN: 4649 302 041. FOUND PITTING DAMAGE ON NR 1 & NR 2 SIDE BEVEL GEAR PN: 4649 303 034. IAW THE ASB THE DAMAGE NOTED IS CAUSE FOR REJECTION OF THE MAIN GEARBOX ASSY.