What happened
The pilot reported that the aircraft was engaged in banner towing operations approximately 200-300 yards offshore from the shoreline. At an altitude of roughly 500 feet, the engine began to sputter and subsequently stopped running completely. The pilot attempted to restart the engine but was unsuccessful. With the powerplant inoperative, the pilot released the tow banner and proceeded to ditch the aircraft in the ocean.
The investigation
A post-crash examination of the engine and its corresponding systems was conducted to determine the cause of the failure. The inspection revealed no evidence of pre-crash mechanical failure or malfunction within the powerplant or associated systems. Despite this thorough examination, investigators could not determine the specific reason for the engine failure.
Findings
The investigation concluded that the engine failure occurred without any detectable mechanical cause. The inability to restart the engine led directly to the ditching of the aircraft in the ocean. No further contributing factors were identified beyond the unexplained loss of power.