What was found
PILOT STATED THAT UPON TAKEOFF THERE WAS A TAIL ROTOR VIBRATION. THEY LANDED THE ACFT & CALLED THE ACFT OOS. WE DISPATCHED A MECHANIC & UPON HIS ARRIVAL IT WAS FOUND THAT THE DISC PACK COUPLING FOR ONE OF THE SHAFTS THAT HAD JUST BEEN REPLACED HAD 1 BOLT THAT WAS REMOVED & LAYING UNDER THE COWLING WHILE THE OTHER WAS HOLDING ON BY JUST A THREAD OF THE NUT. THERE WAS NO EVIDENCE OF TORQUE STRIPE HAVING BEEN APPLIED TO THE BOLT. I AM ATTACHING PICTURES SHOWING THE EXTENT OF THE DAMAGE & THE FINDINGS OF THE POST INCIDENT INSPECTION.