What happened
During the cruise phase of flight, the engine's oil pressure dropped to zero, accompanied by significant engine vibration. In response to the loss of pressure, the pilot elected to shut down the engine and execute a forced landing into a nearby soybean field.
Upon touchdown, the soft terrain caused the nose gear and the left main gear to collapse as they made contact with the ground. There were no injuries reported in the accident.
The investigation
Post-accident investigators determined that the oil filter base-gasket had become extruded from its seat. This extrusion allowed engine oil to leak out of the engine, leading to the loss of pressure.
An examination of relevant documentation revealed that Textron Lycoming Engines of Williamsport, Pennsylvania, had issued Mandatory Service Bulletin number 543A just one day before the accident. The bulletin reported that operating at high oil temperatures could cause the converter plate gasket on the oil filter base to extrude from its seat, creating a leak between the plate and the accessory housing. The bulletin required the removal and replacement of the gasket during every 50-hour oil change.