What was found
AT LEVEL OFF "OIL PRESSURE LOW" LIGHT FLICKERED. FOLLOWED BY LOW OIL PRESSURE INDICATION OF APPROXIMATELY 30PSI. OIL QUANTITY DROPPED TO 0 (ZERO). AT ENGINE IDLE OIL QUANTITY RETURNED TO 2 QUARTS. PRECAUTIONARY LANDING, SINGEL ENGINE OPERATION. CORRECTIVE ACTION: REMOVED AND REPLACED GARLOCK SEAL FOR HYDRAULIC PUMP AND REPLACED STRAINER AND O-RINGS. IAW DC9 MM 79-31, 72-61