What was found
(CAN) WHILE IN CRUISE, IN IMC ON AN IFR FLIGHT FROM AIRPORT TO CANADA, WITH THE INTENT TO BREAK-OFF ON THE APPROACH AND PROCEED HOSPITAL TO DROP OFF OUR PATIENT, THE FLIGHT CREW EXPERIENCED A NOISE THEY BELIEVED WAS LIKELY EMITTING FROM THE MAIN ROTOR. OVER THE NEXT FIFTEEN MINUTES, THE NOISE PROGRESSIVELY AMPLIFIED AND WAS ACCOMPANIED WITH A VERTICAL VIBRATION. AFTER SUCCESSFULLY LANDING AND SHUTTING DOWN, IT WAS NOTICED ONE BLADE TO HAVE A 9 INCH DELAMINATION ON THE LOWER SKIN OF THE LEADING EDGE. APPROXIMATELY BETWEEN 24 AND 33 INCHES FROM THE BLADE TIP. (TC# 20190611010)