60-25-02: Aileron Counterweight

60-25-02 LOCKHEED: Amdt. 229 Part 507 Federal Register December 2, 1960. Applies to All Model 188 Series Aircraft. Compliance required as indicated. As a result of reported cracked aileron counterweight attaching angles, the following is required: (a) At intervals not to exceed 300 hours' time in service, inspect for cracks in the angles which attach the aileron balance-weight brackets to the aileron spar at aileron Stations 13.85, 30.95, 48.01, 82.16, 116.31, 150.46 and 184.61. Cracked angles must be replaced before further flight. (b) The replacement of angles found to be cracked must be made in accordance with either (1) or (2). (1) Original angles may be replaced with parts having the same dimensions as the original parts but fabricated from 0.090-inch thickness AISI 8630 or AISI 4130 steel heat- treated to 150,000-170,000 p.s.i. ultimate tensile strength, cadmium plated and baked. Lockheed Process Specifications Nos. 522, 491, and 170 or FAA approved equivalent must be used for the respective processes indicated. (2) Original angles may be replaced in accordance with the instructions in the kits outlined in Lockheed Service Bulletin 88/SB-451 or FAA approved equivalent. This service bulletin also contains detailed instructions for accomplishing this modification. (c) After replacement of the original parts in accordance with the instructions in (b), subsequent inspections of replaced parts may then be made at normal inspection periods. This supersedes AD 60-11-04. This directive effective December 2, 1960.