What was found
DURING A ROUTINE CROSS-COUNTRY FLIGHT, AN UNUSUAL VIBRATION WAS FELT BY THE FLIGHT CREW AND A PRECAUTIONARY LANDING WAS MADE. POST-FLIGHT INSPECTION FOUND THE OUTPUT HOUSING ON THE INTERMEDIATE GEARBOX WAS COMPLETELY BROKEN AROUND THE CIRCUMFERENCE, AT A POINT JUST BEHIND THE SB 3151A1 BEARING. THIS BROKEN HOUSING NOW ROTATED WITH THE TAIL ROTOR DRIVE SHAFT INSTEAD OF BEING A FIXED PART. SUSPECT BEARING FAILURE.