What was found
PERFORMED AN AIR TURN BACK, DUE TO STRONG ACRID ODOR REPORTED BY THE FLIGHT CREW IMMEDIATELY AFTER TAKEOFF THEN DISSIPATED. LAVATORY SMOKE DETECTORS WERE GOING OFF AS WELL. OXYGEN MASKS WERE NOT DONNED, AND NO EMERGENCY WAS DECLARED. LANDED OVERWEIGHT WITH NO HOT BRAKES. DURING TAXI TO THE GATE, PACK INOPERATIVE MESSAGE APPEARED. FOUND TURBINE SEIZED IN LT ACM. REPLACED LEFT ACM AND LOW LIMIT VALVE IAW AMM 21-51-11.