As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIR TURN BACK. UNABLE TO MAINTAIN CABIN ALTITUDE. FOUND AUX FLAP PARTIALY OPEN, MAIN FLAP CLOSED IAW MEL 21-26-2. PERFORMED TSM 21-31-00-810-888-A. NO DAMAGE FOUND. TESTED GOOD. PRESSURIZED A/C TO 5.8 DPS. PRESSURE HOLD PER AMM 2131-00-710-802-A. OK FOR SVC.