As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIR TURN BACK, ENG 1 BLEED LEAK RESULTING IN AIR TURN BACK FOUND LT WING MFA ILLUMINATED ON MX PANEL. INSPECTED WING PNEUMATIC JOINTS FROM PACK BAY OUT TO LT WING TIP. NO LEAKS NOTED IAW TSM 36-22-00/401. RAN NR 1 ENGINE, NO LEAK INDICATIONS. CHANGED NR 2 OVERHEAT DETECTION CONTROLLER (13HF) OPS CHKD GOOD.