As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) HELICOPTER M/R VIBRATIONS INCREASED RAPIDLY OVER A FEW DAYS. M/R WAS TRACKED AND BALANCED TO WITHIN LIMITS. WITHIN 2 DAYS, VIBRATIONS LEVELS HAD INCREASED BEYOND LIMITS AGAIN. FURTHER INSP REVEALED BLADE DELAMINATION SUSPECTED TO BE ABOVE LIMITS ON THE RED BLADE, AND DELIMINATION WITHIN LIMITS ON FOLLOWING GREEN BLADE. TO FIND THE DELAMINATION THE MR BLADE WAS TAP TESTED.