73-18-03: Front and Rear Wing Spars

73-18-03 ROCKWELL INTERNATIONAL: Amendment 39-1707 as amended by Amendment 39-3201. Applies to Model NA-265-40 Serial Numbers 282-1 and subsequent; Model NA-265-50 Serial Number 287-1; Model NA-265-60 Serial Numbers 306-1 through -139; Model NA-265-70 Serial Numbers 370-1 through -9; and Model NA-265-80 Serial Numbers 380-1 through -61. Compliance required as indicated after the effective date of this AD. To detect possible cracks, corrosion, or breaks in the surface finish in the wing spars and related areas, accomplish the following: (a) On or before June 18, 1974, unless previously accomplished within one year, and at intervals not to exceed two years thereafter, inspect the upper and lower flanges of the front and rear spars in the area of the wing center section, and the lugs on the rear spar and wing trailing edge panel rib, per the instructions of Rockwell International, Inc., Sabreliner Division Service Bulletin No. 73-11, dated June 18, 1973, or later FAA-approved revisions, or an equivalent inspection approved by the Chief, Aircraft Engineering Division, FAA Western Region. (b) Prior to further flight, if cracks, corrosion, or breaks in the surface finish are found in the front or rear spars in the area of the wing center section, replace with like serviceable parts, or repair in a manner approved by the Chief, Aircraft Engineering Division, FAA Western Region. (c) Prior to further flight, if cracks are found in the lugs on the rear spar and wing trailing edge rib, replace with like serviceable parts, or repair in a manner approved by the Chief, Aircraft Engineering Division, FAA Western Region. (d) Airplanes may be operated in accordance with FAR 21.197 to a base where maintenance is to be performed. Amendment 39-1707 became effective October 8, 1973. This Amendment 39-3201 becomes effective May 5, 1978.