What was found
(CAN) SHORTLY AFTER TAKEOFF, THE HYDRAULIC SYSTEM A LOW PRESSURE LIGHTS ILLUMINATED. THE FLIGHT CREW DETERMINED THAT A LEAK HAD DEPLETED THE HYDRAULIC SYSTEM A FLUID, COMPLETED THE APPROPRIATE CHECKLIST AND A RETURN TO BASE WAS CONDUCTED. THE A/C LANDED SAFELY WITHOUT FURTHER INCIDENT. UPON INSPECTION, MAINTENANCE DETERMINED THE CAUSE OF THE LEAK TO BE FROM A RUPTURED PLUG LOCATED ON THE RT ELEVATOR POWER CONTROL UNIT. THE POWER CONTROL UNIT WAS REPLACED IAW THE AMM AND THE A/C WAS THEN RETURNED TO SERVICE.