As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
HELICOPTER EXPERIENCED A PROGRESSIVE LATRIAL VIBRATION. SUBSEQUENT INSPECTION FOUND 2 CRACKS FROM THE PITCH PIN SLOT AREA OF THE MAST. ONE CRACK FROM THE TOP OF ONE SLOT AND ANOTHER CRACK FROM THE BOTTOM OF THE SAME SLOT PROGRESSING THE OPPOSITE DIRECTION. THE TOP CRACK IS APPROX 1.6 INCHES AROUND THE DIAMETER OF THE MAST AND THE BOTTOM CRACK IS APPROX 1.3 INCHES.