What was found
98-243 AT CRUISE, FL 330, NR 1 OIL FILTER BYPASS LIGHT CAME ON WHEN THROTTLE WAS RETARD TO IDLE, LIGHT WENT OUT FOR APPROX 2 MIN, THEN CAME BACK ON AND REMAINED ON. ENG WAS SHUT DOWN IN ACCORD WITH RED TAB. OIL TEMP AND PRESS & QUAN NORM. REMOVED AND REPLACED LOW OIL PRESS SWITCH AND RAN. OPER AND LEAK CK ON NR 1 ENG PER MM 79-33-0, AND JET RUN HANDBOOK. OPER CK GOOD. LEAK CK GOOD.