Accident Overview
After taking off from Moreton Airpark, the pilot executed a right turn to a southeasterly heading, intending to fly down the Hassayampa riverbed before returning. The pilot planned to demonstrate a hissing sound the aircraft made after engine shutdown to the mechanic, who was also on board. This symptom had developed after the mechanic had installed new fuel bladders. While discussing the symptom, the pilot noticed a bright flash.
Witness Observations
Witnesses saw the aircraft flying down the Hassayampa riverbed at an altitude of about 10 feet above ground level. They described the weather at the time as clear and calm.
Wire Strike Evidence
Investigators found that six aluminum electrical transmission lines spanning the Hassayampa riverbed had been broken. The lowest three wires were 24 feet higher than the riverbed at the lowest point. The next set of three wires was 3 feet higher. The wires were marked with an orange ball.
Mechanical Findings
Investigators found no mechanical discrepancies with the aircraft.