Incident Overview
On 19 May 2017, during a VFR flight in the FIR EPWA, the pilot-in-command of a Cessna 172 observed low oil pressure, though still within the safe range. The pilot decided to abort the flight and land. After landing, maintenance personnel inspected the oil system and found three small metal filings on the oil filter.
Engine Examination
Due to the shape of the filings, the engine was removed and sent to the maintenance organization that had performed its major overhaul, as it was still under warranty. The organization conducted an examination and noted unusual wear on the main and connecting rod bearings. This wear could have been caused by an improper first start after a long storage period or a break in operation. However, no definitive cause for the metal filings was established.
Outcome
Following the overhaul, the engine was reinstalled on the aircraft and returned to service without any further abnormalities detected. The operator informed all personnel of the incident and emphasized the importance of monitoring for metal filings during maintenance inspections.
Probable Cause
The investigation did not determine the cause of the incident.