What was found
CABIN INTERNAL STRUCTURE FRAME CRACKED AT FASTENER LOCATION WHERE A/C DISTRIBUTION DUCT SUPPORT BRACKET IS SECURED TO FRAME AT STATION 1580, BETWEEN STRINGER 8R & 9R. MARKED CUT OUT DAMAGED SECTION OF FRAME & INSTALLED REPAIR DOUBLERS IAW SRM 53-00-07 REPAIR 1. INITIATED DIP TO INSPECT REPAIR 12,000 FLIGHT CYCLES FROM INSTALLATION OR 50,000 AIRFRAME FLIGHT CYCLES WHICHEVER COMES FIRST & AT INTERVALS OF 12,000 FLIGHT CYCLES THEREAFTER.