As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DFW - FLT 1618 - AFTER TAKEOFF FLOW LIGHT AND CABIN DESCENT OF 300 FEET PER MINUTE DURING CLIMB AT 31,000 FEET POP AND NOISE UNDER FIRST CLASS CABIN REPORTED BY FLIGHT ATTENDANT. RETURNED AND LANDED DFW WITHOUT FURTHER INCIDENT. DURING DESCENT FLOW LIGHT EXTINGUISHED. REPLACED OUTFLOW VALVE ACTUATOR. SYSTEM GROUND CHECK NORMAL OPERATION. (M)