Accident Details
The aircraft was conducting a pipeline observation flight. Witnesses reported that the aircraft climbed at a steep angle with full engine power at the point where pipeline personnel indicated the observation would have been completed. Subsequently, the aircraft's wing and nose dropped, and it descended, disappearing from view behind trees. The engine noise, still at full power, ceased abruptly, followed by the sound of impact with a river.
Post-Crash Examination
Examination after the crash showed that the aircraft collided with trees before entering the river. The impact occurred during a descent in a nose-down attitude at a slow speed. Inspection of the engine, airframe, and flight controls found no evidence of pre-impact failure or malfunction.
Toxicology and Medical Findings
Postmortem examination and toxicology testing of specimens from the pilot and two passengers revealed no findings that could be considered causal to the accident.