What was found
LT HORIZONTAL STABILIZER #4 RIB STIFFENER # 4 CRACKED. REMOVED DAMAGE AT LT HORIZONTAL STABILIZER #4 RIB STIFFENER #4 IAW SRM 51-10-02-0G-0 AND SRM 55-10-09-2R-4. PERFORMED HFEC INSP. ON RIB#4 STIFFENER #2 WEB IAW B737 NDT PART 6; 51-00-00; PROCEDURE 23. CRACK REMAINED AND MARK . PERFORMED HFEC AT CUT OUT IAW NDTM PART 6; 51-00-00 PROCEDURE 23. NO CRACKS. PERFORMED HFEC HOLE PROBE INSPECTION ON ALL REMOVED FASTENER LOCATIONS IAW NDTM PART 6; 51-00-00; PROCEDURE 16. NO CRACKS.VERIFIED THE CUT EDGE SURFACE ROUGHNESS SMOOTHER THAN 63 MICRO INCHES RA IN IAW SRM 51-20-13-0G-0.LOCATED AND DRILLED REPAIR PARTS AND RIB AS PER B737-700 SRM 55-10-09-2R-4 REPAIR 4 AND SRM 51-40-05-0G-0. TREATED AND PRIMED REPAIR PARTS AS PER B737-700 SRM 51-20-01-0G-0 AND SOPM 20-41-02.INSTALLED REPAIR PARTS AS PER B737-700 SRM 55-10-09-2R-4 FIG. 202; STEPS M THRU Q.