73-19-04: Main Rotor Blade Grip

73-19-04 BELL: Amdt. 39-1711. Applies to Model 47 series helicopters certificated in all categories that are equipped with main rotor blade grips, P/N 47-120-135-1, -2, -3 or P/N 47- 120-252-1, -3. Compliance required within the next 100 hours' time in service after the effective date of this A.D., unless already accomplished. To prevent possible fatigue cracks from developing, accomplish the following for each main rotor blade grip: (a) Inspect the grip thread relief fillet. The inboard radius and bottom of the fillet must have a smooth finish and be free of nicks or sharp tool marks (Ref. Figure 1-22 of Bell 47D- 1, 47G and 47G-2 Maintenance and Overhaul Instructions). (b) Inspect the root radius of the 4 1/2 inch diameter threads for sharp notches. The root radius must be smooth and free of sharp notches or grooves. (c) If the grip thread relief fillet is not as specified in subparagraph (a) or has nicks or sharp tool marks, or if the thread root radius has a sharp notch or groove, replace the affected grip prior to next flight, except the helicopter may be flown in accordance with FAR 21.197 to a base where the grip may be replaced. This amendment becomes effective October 10, 1973.