Cessna 172P N5448K accident near Tamuning

Probable cause

The pilot's inadequate preflight inspection, which resulted in oil exhaustion and a subsequent total loss of engine power during cruise flight.

NTSB analysis

The commercial pilot reported that, during the local sightseeing flight, he noticed fire sparks and smoke starting to fill the cabin. Shortly after, the engine lost all power, and the airplane started to shake violently. The pilot decided to return to the airport, and while en route, he attempted to restart the engine without success. When he realized there was insufficient altitude to land on the runway, he initiated a forced landing to a nearby field. The airplane impacted terrain short of the airport perimeter fence and sustained substantial damage.

An engine examination revealed that the engine oil filler cap was not secured, and evidence of oil was found around the No. 4 cylinder and intake pipes. The pilot reported that he checked the oil level before the first flight of the day and then flew 10 more flights that day but did not check the oil level before those flights. The Pilot's Operating Handbook indicated that the oil quantity is to be confirmed and the oil filler cap is to be secured before each flight. It is likely that the pilot did not properly secure the oil filler cap during the preflight inspection before the first flight of the day and did not verify that it was secured before any of the following 10 flights, which resulted in a gradual leak of engine oil and subsequent engine seizure. Further, his failure to check the oil before the following 10 flights prevented him from identifying that the oil had leaked out and was at an insufficient level.

Text from the NTSB. Open the NTSB docket for WPR17LA216 for the full record.