What was found
AIRCRAFT WAS GROUNDED: ON TAKEOFF ROTATION FLIGHT CONTROL LIGHT AND LOW PRESSURE SYSTEM A ENGINE AND ELECTRIC LIGHT ILLUMINATED. HYDRAULIC QUANTITY A DROPPED TO 61% WITH ODOR IN COCKPIT. RETURNED TO JFK PRECAUTIONARY LANDING. EMERGENCY WAS DECLARED. AIRCRAFT WAS OVERWEIGHT FOR LANDING. HYDRAULIC A PRESS REMAINED 3000 PSI. REPLACED SYSTEM A HYDRAULIC RETURN FILTER (AALA202109230208), ELECTRONIC DEMAND PUMP CASE DRAIN FILTER (AALA202109242854), ELECTRONIC DRIVEN MOTOR PUMP CASE DRAIN FILTER (AALA202109240230), ELECTRONIC DEMAND PUMP/ELECTRONIC DRIVEN MOTOR PUMP PRESSURE MODULE SYSTEM A FILTER (AALA202109245460) AND LEFT ENGINE DRIVEN HYDRAULIC PUMP SUPPLY HOSE. ACCOMPLISHED HIGH POWER RUN NO LEAKS OR ODORS NOTED HYDRAULIC PRESSURE AND QUANTITY NORMAL.