What was found
PILOT NOTICED HYD FLUID LEAKING ON GROUND AND LT SIDE OF ACFT. MECHANIC ARRIVED AND SERVICED NR2 HYD SYS. PERFORMED GROUND RUN AND FOUND FLUID SQUIRTING FROM B-NUT/ T-FITTING ON THE RETURN LINE, COMING FROM THE FILTER MANIFOLD. DISCOVERED B-NUT WAS NOT EVEN FINGER TIGHT. TIGHTENED B-NUT AND ALL SURROUNDING FITTINGS, RESERVICED HYD RESERVOIR. PERFORMED GROUND RUN FOR 5 MINUTES WHILE PILOT PERFORMED A HYD SYS CHECK WHICH CHECKED GOOD. AFTER SHUTDOWN MECHANIC CHECKED FOR LEAKS- NONE FOUND. PERFORMED MX HOVER, THEN FLIGHT. ALL CHECKS WERE NORMAL AND NO FURTHER LEAKS WERE NOTICED. ACFT RETURNED TO SERVICE.