What was found
(CAN) NR 2 ENGINE MAGNETIC PLUG WARNING LIGHT CAME ON IN-FLIGHT. PILOT REDUCED POWER TO IDLE ON NR 2 ENGINE AND RETURNED TO RAMP. LOWER MAGNETIC PLUG HAD HEAVY ACCUMULATION OF FINE METAL PARTICLES. FURTHER INVESTIGATION REVEALED THAT NR 2 1/2 BEARING WAS THE SOURCE OF METAL AND THE SPUR ADAPTER GEAR SHAFT WHERE NR 2 1/2 BEARING RIDES HAS DAMAGE FROM THE BEARING.