Piper PA28R N57355 accident near Carlsbad, California

Probable cause

A failure of the No. 2 piston connecting rod bearing due to oil starvation for reasons that could not be determined, which resulted in a complete loss of engine power.

NTSB analysis

The flight instructor was conducting an instructional flight when the accident occurred. During the takeoff climb, the pilots observed an abnormal oil pressure indication and elected to return to the airport. As they were returning to the airport, there was a complete loss of engine oil pressure followed by a total loss of engine power. Unable to maintain altitude, the pilots elected to make a water landing. The pilot receiving instruction flew the airplane to the surface. The flight instructor notified air traffic control (ATC) of the engine failure and intended landing site. They touched down about 50 yards from the shoreline with the landing gear up and were able to egress from the airplane as it floated

Postaccident examination of the engine revealed that the engine case was breached between the pushrod tubes of the No. 2 cylinder, showing a visible puncture along the pushrod tube channel. Internal examination of the engine revealed that the No. 2 connecting rod separated from the crankshaft. Thermal damage was observed along the shank of the No. 2 cylinder connecting rod. The No. 2 connecting rod bearing had separated from the journal, which was mechanically damaged. A remaining section of the No. 2 connecting rod end cap displayed score marks consistent with interfacing at the No. 2 crankshaft journal. Internal thermal discoloration and damage identified during the engine teardown were consistent with a lack of oil. While it’s likely that lubrication deprivation resulted in a total loss of engine power, a blockage or malfunction of the oil system could not be located due to engine damage that resulted from being submerged in salt water.

Text from the NTSB. Open the NTSB docket for WPR23LA094 for the full record.