As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
SHIP 6711 -ATB - DUE TO LT ENG BLEED AIR CYCLING CAUSING PACK TO TRIP. CORRECTIVE ACTION: REPLACED LEFT HP VALVE, HP CONTROLLER AND 450 SENSOR FOR THE LEFT BLEED. ACM CHANGED FOR THE RT PACK. ALL SENSE LINE LEAK CHECK GOOD. REPLACED LEFT FAN AIR TEMP SENSOR PER B757 AMM 36-11. OPS CHK NML. (9197780)