What was found
RH HORIZONTAL STABILIZER RIB #4 STIFFENER #3 LOWER SECTION CRACK<[01] SUMMARY<BR>REMOVED DAMAGE AT RIB #4 STIFFENER #3 AS PER B-737 SRM 55-10-09-2R-4.<BR>REMOVED CRACK ON #3 STIFFINER; AREA MARKED AS PER B-737 SRM 55-10-09-2R-4.<BR>LOCATED AND DRILLED REPAIR PARTS AS PER B-737 SRM 55-10-09-2R-4<BR> & PERFORMED ROUGHNESS TEST ON REPAIR PARTS FOUND THEM TO BE SMOOTHER THAN 125 MICROINCHES RA & PERFORMED ROUGHNESS TEST ON INITIAL PARTS FOUND THEM TO BE SMOOTHER THAN 36 MICROINCHES RA AS PER B-737 SRM 51-20-13-0G-0<BR>TOOL USED: BC 172331. NO CALIBRATION DUE DATE<BR>TREATED AND PRIME REPAIR PARTS AND INITIAL PARTS AS PER B-737 AMM 51-21-41-370-803 & AMM 51-21-72-370-801.<BR>ACCOMPLISH INSTALLATION OF RIB #4 STIFFENER #3 REPAIR AS PER B-737 SRM<BR>55-10-09-2R-4 & SRM 51-40-02<BR>ACCOMPLISH SEALANT FINISH AS PER B-737 SRM 51-20-05-0G & AMM 51-20-99/701;[02] VERIFIED STEP 1.