As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
BLD 1 LEAK CLIMBING THROUGH FL180. AIR RETURN TO CMH. WE BURNED OFF THE EXTRA FUEL FOR A NORMAL LANDING. "TRANSFERRED TO NRWC 674-CMH-04717" G. DAVID GOULD JR. 151543-C/A-FOUND COUPLING #12 OM #1 PACK VALVE LEAKING. REMOVED AND REPLACD COUPLING IAW ETN-EM-21-056. OPS AND LEAK CHECK GOOD IAW AMM 21-51-01. OPS CHECK GOOD. NO LEAKS DETECTED.