What was found
30 MINUTES INTO A FLIGHT A LOW OIL PRESSURE WARNING CAME ON. THE PILOT PERFORMED A PRECAUTIONARY IN FLIGHT SHUTDOWN AND RETURNED TO HOME BASE, LANDING WITHOUT INCIDENT. THE AFT BEARING SCAVENGE TUBE WAS FOUND TO HAVE CRACKED AND DEPLETED THE OIL TO AN UNACCEPTABLE LEVEL. THE SCAVENGE LINE WAS REPLACED AND THE ENGINE GROUND RUN AND RETURNED TO SERVICE. THE CRACK MOST LIKELY RESULTED FROM UNDO STRESS APPLIED TO THE LINE DURING AN UNRELATED MAINTENANCE ACTION. THE AGE AND BRITTLENESS OF THE LINE MAY HAVE BEEN A CONTRIBUTING FACTOR.