On January 26, 2004, a Cessna 120 (registration N1961V) was involved in an aviation accident near Lonoke, AR. Investigators recorded the probable cause as: The loss of engine power for undetermined reasons. A contributing factor was the dusk lighting conditions and unlit airfield. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.
A 380-hour pilot performed a forced landing after the engine emitted knocking sounds and lost power. Unable to stop before trees, the pilot turned off the runway, striking a ditch and nosing over. Post-accident examination revealed no mechanical deficiencies; the cause of the power loss remained undetermined.
Accident Sequence
During cruise flight, the pilot, who had logged 380 hours, reported hearing two loud knocking sounds from the engine. The engine subsequently began to vibrate and lose power. The pilot initiated a forced landing to an unlit airfield located east of the airplane's position. Upon touchdown and during the landing roll, the pilot realized that the airplane would not stop before encountering trees at the end of the runway. To avoid the trees, the pilot turned the airplane left, causing it to exit the runway. The airplane then impacted a ditch, nosed over, and came to rest inverted.
Post-Accident Examination
An on-scene examination of the airplane included an engine run. The engine was started and ran for approximately 15 seconds before it was shut off using the magneto switch. Manual rotation of the propeller confirmed that valve train continuity was established throughout the engine, and all four cylinders produced compression. No mechanical deficiencies were noted during the examination. The reason for the initial loss of engine power remained undetermined.