As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CLIMBING THROUGH 23,000 FT, AIRCRAFT EXPERIENCED REAR BAY OVERHEAT WARNING FOLLOWED BY CABIN ALTITUDE STARTING TO CLIMB. ACFT RETURNED TO POINT OF DEPARTURE. MAINTENANCE INSPECTOR FOUND ACM INLET DUCT BROKEN, ACM OUTLET CLAMP BROKEN, AND ACM TURBINE BLADES AND BEARINGS DAMAGED. WE SUSPECT THE INLET DUCT BROKE ALLOWING THE ACM TO OVERSPEED DAMAGING THE ACM AND BREAKING THE OUTLET CLAMP.