Engine Cylinder Separation Leads to Forced Landing in Soybean Field (N76SA)

Incident Overview

The airplane sustained substantial damage during a forced landing to a soybean field. The pilot reported that while in cruise flight, the engine shuttered and developed serious vibration. According to the pilot, "at 3,500 feet engine ejected right rear cylinder head. Cowling stayed hinged on left. Oil spray on windshield and fire on lower right of firewall." The pilot shut down the engine and attempted to reach Staton Airport, but ultimately had to perform a forced landing in a bean field, damaging the right wing during the landing.

Engine Inspection Findings

Post-incident inspection of the engine confirmed that the number three cylinder had separated during flight. The cylinder itself was never located or recovered. The number three piston and connecting rod had separated from the crankshaft and were found at the bottom of the engine compartment. All of the number three cylinder through bolts and case studs were fractured. Several of the through bolts and studs exhibited fracture features consistent with fatigue, while the remaining bolts and studs displayed fracture features consistent with overload.