What was found
AIRCRAFT WAS SECURED ON PLATFORM OFFSHORE. ALL MAIN ROTOR BLADES WERE SECURED USING SIKORSKY TIE DOWN CLAMPS. WINDS OF 80+ MPH CAUSED ONE M/R BLADE TO BREAK OFF APPROXIMATELY 3 FEET FROM ROOT. SPECIAL INSPECTION WAS C/W AND BLADE AND SPINDLE CHANGED. AIRCRAFT WAS FERRIED TO MAIN BASE FOR FURTHER INSPECTION. NO DEFECTS WERE FOUND. CAUSE OF PROBLEM WAS CLAMPS DO NOT HOLD IN HIGH WINDS. RECOMMEND USING SOCK TYPE BOOT AND THROW CLAMPS AWAY.