What was found
DURING C-CHECK, CORROSION AND CRACKING WAS FOUND IN THE 65B04175-1 BS 780 FRAME SHEAR TIE BETWEEN S-46L AND -47R. THE DAMAGE WAS TRIMMED OUT AND REPAIRED IAW NRC 699 AND SRM 53-10-04, FIG 4. THE 65B04175-1 FRAME SHEAR TIE IS MADE FROM 0.056 INCH THICK 7075-0 ALUMINUM SHEET IAW QQ-A-250/13 HEAT TREATED TO T6 AFTER FORMING. THE REPAIR CONSISTS OF AN 0.071 INCH THICK DOUBLER MADE FROM 7075-T6 ALUMINUM INSTALLED USING MS20470D6 RIVETS. PART 1 OF THIS EO DOCUMENTS THE FRAME REPAIR NRC 699 AND SRM 53-10-04, FIG 4 PART 2 OF THIS EO COMPLIES WITH THE REPETITIVE INSP REQUIREMENTS OF THE PART 1, CATEGORY B REPAIR. THE REPAIR ACCOMPLISHED IAW PART 1 AND THE INSP IAW PART 2 OF THIS EO ARE FAA APPROVED IAW SRM 53-10-04, FIG 4. EO 4753B278.