What was found
FLT 1724 FROM KROC TO KPHL. ON APPROACH TO KPHL OBSERVED A COMPLETE LOSS OF B-SYSTEM HYDRAULIC FLUID. ACCOMPLISHED ABNORMAL CCIA AIRCRAFT OPERATIONS MANUAL A-05-3, ADVISED ATC AND DECLARED EMERGENCY AS A PRECAUTIONARY. AIRCRAFT LANDED WITHOUT INCIDENT. AIRCRAFT WAS INSPECTED AND FOUND A B-NUT LOOSE ON RIGID RETURN LINE TO ELEVATOR FEEL CONTROL UNIT. TIGHTENED AND SECURED “B” NUT IAW B727 MM 20-10-5, SERVICED HYDRAULIC SYSTEM TO FULL AND NO LEAKS WERE NOTED DURING SYSTEM CHECKS. AIRCRAFT RETURNED TO SERVICE