What was found
LEFT HORIZ STAB RIB 4 STA 120.30 STIFFENER 3 APPEARS TO BE CRACKED AT LWR AREA. 8-46 / PERFORMED HFEC AT LEFT HORIZONTAL STAB RIB #4 STA 120.30 STIFFENER 3; FOUND CRACKED. CUT OUT DAMAGED AREA; PERFORMED HFEC AT CUT OUT (STIFFENER 3) NO CRACK NOTED. LOCATED AND DRILLED REPAIR PARTS (KIT PD:7551022). INSTALLED REPAIR PARTS AT LEFT HORIZONTAL STAB RIB #4 STA 120.30 STIFFENER 3 PER REF B737-700 SRM 55-10-09-2R-5; NDTM PART 6 51-00-00 PROCEDURE 23 AND PROCEDURE 16; B737-700 SRM 51-20-01-0G-0