What happened
Following takeoff from Moreton Airpark, the pilot executed a right turn to a southeasterly heading. The flight path was intended to follow the Hassayampa riverbed before returning to the airpark. Onboard the aircraft was a mechanic whom the pilot intended to demonstrate an unusual hissing sound that had occurred after the engine was shut down. This specific symptom had been noted following the installation of new fuel bladders.
While the crew was discussing this mechanical symptom, a bright flash was observed. Witnesses reported seeing the aircraft flying approximately 10 feet above ground level within the Hassayampa riverbed. At the time of the accident, weather conditions were described as clear and calm.
The investigation
Investigators examined six aluminum electrical transmission lines that spanned the Hassayampa riverbed and found they had been broken. The lowest set of three wires was positioned 24 feet above the riverbed at its lowest point, while the subsequent set of three wires was located 3 feet higher than the first set. These wires had been marked with an orange ball. Upon inspection of the aircraft, investigators found no mechanical discrepancies.