As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLIGHT CREW REPORTED AIRCRAFT WOULD NOT PRESSURIZE. TROUBLESHOOTING REVEALED THE AIR CONDITIONING NOSE DISTRIBUTION DUCT LEAKING. THE 'CROSSOVER DUCT' (WELDED ALUMINUM SECTION) CRACKED AND SEPARATED 10.2 INCHES LONG AT THE UPPER FORWARD LATERIAL WELD. THIS PORTION OF THE DISTRIBUTION DUCTING IS NOT ACCESSIBLE FOR INSPECTION WITH CURRENT INSPECTION PROCEDURES.