What was found
DURING FLIGHT, NR 2 NACELLE OVERHEAT LIGHT CAME ON APPROXIMATELY FIVE MINUTES AFTER LEVELED OFF. SHUTDOWN ENGINE AND ACCOMPLISHED AIR TURNBACK TO CHS, AIRCRAFT LANDED WITHOUT INCIDENT. FOUND F-DUCT SEAL DETERIORATED. RESEALED F-DUCT PER MM CH 72 AND ACCOMPLISHED ENGINE RUN, SYSTEM OPS CHECKED GOOD, NO LEAK NOTED.