Incident Overview
During the execution of practice maneuvers at an altitude of 3,500 feet, the flight crew experienced an unexpected loud noise followed by the windshield becoming obscured by oil. This necessitated an immediate forced landing. During the landing, the aircraft collided with a fence and ditch.
Engine Examination
Post-incident disassembly of the engine revealed that the #4 connecting rod had fractured. Additionally, the top connecting rod nuts on the #2 and #4 cylinders were found to be loose. A metallurgical examination further disclosed that the #4 bottom connecting rod bolt had failed due to overload, and the #4 connecting rod itself had failed as a result of high stress, low cycle fatigue.
Findings
No other contributing factors or conditions were identified. The investigation did not specify the aircraft type, registration, operator, or the number of occupants. Similarly, details regarding injuries, damage extent, time of day, weather conditions, or air traffic control involvement were not provided in the source material.