What was found
AFTER TAKEOFF & DURING GEAR RETRACTION, THE FLIGHT CREW HEARD A THUMP FOLLOWED BY INCREASED WIND NOISE. IT WAS NOTED THE GEAR INDICATING DOWN WITH THE GEAR HANDLE IN THE UP POSITION, THREE GREEN GEAR LIGHTS WITH A RED DISAGREE LIGHT WAS INDICATED. ON THE EICAS, THE FLIGHT CREW RECEIVED AN AMBER HYD VOLUME LOW A & HYD PTU FAIL. THE QTY & PRESS OF THE A SIDE HYD BOTH INDICATED ZERO. THE HYD TEMPERATURE WAS HOLDING STEADY. THE ACFT DIVERTED TO SWF, AN UNEVENTFUL LANDING WAS ACCOMPLISHED & THE ACFT WAS TOWED OFF THE RUNWAY. A RUPTURED RT MLG ACTUATOR HOSE WAS LATER DISCOVERED.