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. THE M/R BLADE WAS TAP TESTED TO FIND THE DELAMINATION.