What was found
DURING INSPECTION, A 1 INCH CRACK WAS FOUND JUST LEFT OF BL 0 AT STA 379 IN THE SKIN AFT OF THE E/E AIR DUCT CUTOUT. THE CRACK IS TYPICAL OF THOSE COVERED BY BOEING S/B 737-53-1117, REV 1. DURING REMOVAL OF THE EXHAUST DUCT, THE INTERNAL SURROUND DOUBLER WAS TORN RESULTING IN A 1 INCH BY 1.25 INCH CUTOUT. REPAIRED AS REQUIRED BY BOEING SERVICE BULLETIN 737-53-1117, WHICH INSTALLS A DOUBLER REF DL ERA 303053-14.