Model 47 aircraft.
Compliance is required as indicated, unless already accomplished.
Reports have been received of numerous main rotor blade grips being found with fatigue cracks in the retention thread area and two accidents have occurred as a result of grip failure. Failure of the grip will result in loss of a main rotor blade. The original issue of this directive mandated an initial inspection of the main rotor grips at 1200 hours air time, with recurring inspection intervals of 300 hours. For grips having more than 600 hours air time since new, perform the initial inspection within the next 25 hours air time and at scheduled intervals of 300 hours air time thereafter. This directive becomes effective 30 November 2000.