As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFTER TAKEOFF ACFT HAD LEFT BLEED PROBLEM. LEFT PACK SHUT DOWN. RETURNED TO DEPARTURE. REPLACED HPFAC AND ASCPC PER AMM. PERFORMED PNEUMATIC LINE LEAK CHECKS- ALL PLUMBING CHECKED NORMAL. PERFORMED GROUND TEST VIA THE MAT- ALL TEST PASS.