70-18-04 FAIRCHILD HILLER HELICOPTERS: Amdt. 39-1075. Applies to 1100 series helicopters certificated in all categories.
Compliance required within the next 25 flight hours of the effective date of this A/D unless already accomplished.
To prevent failure of transmission vertical struts and mounts:
(1) Strip epoxy paint from weld areas of transmission vertical struts and mounts P/N 24-28030-1 and -2 with commercial paint stripper.
(2) With dye penetrant inspect weld areas for cracks.
(3) Replace any cracked part prior to further flight.
(4) Refinish stripped areas with two coats of zinc chromate.
(5) Repeat above procedure at each succeeding 100 flight hours.
This amendment is effective September 15, 1970.