78-21-05 SIKORSKY AIRCRAFT: Amendment 39-3322. Applies to S-58BT, S-58DT, S-58ET, S-58FT, S-58HT, and S-58JT helicopters certificated in all categories.
To prevent possible tail rotor instability accomplish the following:
Within 200 hours time in service or three months, whichever comes first, after the effective date of this AD, unless already accomplished, complete the following:
(a) Install improved abrasion strips, Sikorsky Modification Kit 58070-10008-011, on tail rotor blades, P/Ns S1615-30100-3, -4, -7, -10, -11, -15, -16, -041, -042, and -043. This modification is covered by Sikorsky Service Bulletin No. 58B15-18.
(b) Install Sikorsky control rod assembly, P/N 58400-64010-101.
This modification is covered by Sikorsky Service Bulletin No. 58B40-5.
This amendment becomes effective November 30, 1978.