52-01-02 BELL: Applies to All Models 47B, and 47B3 Helicopters and to Model 47D Helicopters Serial Numbers 1 to 79, Inclusive.
Compliance required at next 300-hour overhaul, but not later than March 1, 1952.
To increase the safety of the main rotor blade equalizer horns and drag brace fittings, which have failed in accidents involving damage to the main rotor, replace the existing equalizer horn (P/N 47-120-027-2) and drag brace fitting (P/N 47-110-145-2) with revised parts P/N 47- 120-167-1 and P/N 47-110-235-1, respectively.
(Bell Service Bulletin No. 77 covers this same subject.)