What was found
DURING RETURN TO BASE, COMPLETE HYD SYS LOSS. AFTER LANDING, SEVERE HYD LEAK NOTED, BUT NO CAUSE FOUND PRIOR TO CLEAN UP. AFTER SERVICE AND RUN-UP, FOUND LINE TO HYD PUMP RUPTURED. SUBMITTER BELIEVES LINE DAMAGED DURING 300 HR SPLINE CHECK INSP WHERE PUMP IS SEPARATED FROM TACH GEN. METHOD FLEXES LINE.