What was found
PRIOR TO ENGINE START, AS THE PILOT SWITCHED ON BATTERY POWER, THE MAIN TRANSMISSION CHIP DETECTION ILLUMINATED. THE PILOT IMMEDIATELY ABORTED THE START SEQUENCE AND CALLED THE MECHANIC TO COME INSPECT THE AIRCRAFT. THE MECHANIC/S COMPLETED EO 23-6300-EO-669 PART 5,AND SCHEDULED PART 6. UPON EXECUTION OF PART 6 OF 23-6300-EO-669, THE MECHANICS FOUND THE LT PINION GEAR WORN BEYOND LIMITS. ACCORDING TO TECHNICAL DATA, THIS IS CAUSE FOR A MAIN GEARBOX REMOVAL AND REPLACEMENT. THIS AIRCRAFT REMAINS OUT OF SERVICE AT THE TIME OF THIS SUBMISSION AWAITING PARTS AND TOOLING TO COMPLETE THIS MAINTENANCE EVENT.