Incident Overview
A flight instructor and his student were en route to their destination when the engine cowling and instrument panel began to shake violently about halfway through the flight. The instructor adjusted the mixture setting and checked the instruments, noting that the engine oil temperature and pressure remained within normal ranges. Shortly thereafter, the engine began shaking and then stopped completely, while gray smoke filled the cockpit.
Emergency Landing
The flight instructor observed flames emanating from the nose area of the aircraft. Through the smoke and haze, he attempted to locate a suitable landing site and elected to land in an agricultural field. The airplane touched down on the main landing gear, but as the nose wheel contacted the ground, it dug into the dirt, causing the aircraft to nose over.
Post-Landing Events
After exiting the airplane, the instructor and student observed a small fire near the front engine area, which extinguished itself without intervention.
Engine Examination
According to a Federal Aviation Administration (FAA) inspector, the engine was examined and a large hole was found on the bottom side of the engine crankcase between the number 1 and number 2 cylinders. A concentration of oil was noted on the inside of the cowling at the same approximate location as the crankcase hole. Further inspection revealed that the number 1 connecting rod cap had separated from the connecting rod during engine operation. The reason for this occurrence is undetermined.