NTSB Factual Report

On April 5, 1995, at 1709 mountain standard time, an Ayres S2R- T34, N3105B, collided with power lines near Stanfield, Arizona. The 2-place training version of the S2R aircraft was operated by Custom Farms Air Service of Stanfield, and was demonstrating a GPS-based application guidance system developed for agricultural aircraft operators. Visual meteorological conditions prevailed at the time and no flight plan was filed for the operation, which was conducted under the provisions of 14 CFR Part 91 of the Federal Aviation Regulations. The aircraft was destroyed in the collision sequence and postcrash fire. The certificated commercial pilot sustained fatal injuries; however, the passenger receiving the system demonstration incurred minor injuries. The flight originated from a private airstrip near Stanfield on the day of the accident at 1615.

The surviving passenger, who holds a commercial pilot certificate with a helicopter rating, stated that he had no memory of the accident flight. The passenger, an employee of an east coast agricultural aircraft operator, said he was seated in the rear seat and was observing the use of a GPS-based guidance system which his company had recently purchased.

The operator stated that the company is a distributor for the guidance system and was conducting training classes for purchasers of the system. The company reported that the aircraft did not have chemicals on board, and the purpose of the flight was to familiarize the students with system operation during typical aerial application operations.

One ground witness was located 1 mile away from the accident site. He observed the aircraft in a turn near the edge of a farm field, then saw the black smoke rising from the accident site.

The aircraft was examined by a Federal Aviation Administration (FAA) airworthiness inspector from the Scottsdale, Arizona, Flight Standards District Office. He reported observing wire contact signatures on the right main landing gear and spreader booms. The aircraft appeared to be traveling from a southwest to northeast direction when it contacted four 1-inch diameter aluminum power lines strung between poles at the western boundary of a farm field. Three of the lines were noted to be severed.

The inspector noted that the wire contact signatures on the spreader boom leading edge were oriented on a 45-degree angle to the vertical axis and pointed in toward the fuselage. Three separate sections of the wire were observed to have ends with a cut appearance, with no evidence of ductile deformation or necking evident.

The propeller was observed to display leading edge damage, chordwise scoring, torsional twist signatures, and tip bending opposite the cambered side.

The inspector stated that he found no evidence of mechanical discrepancies in his examination.

NTSB Probable Cause

the pilot's failure to maintain an adequate visual lookout for, and clearance from, obstacles while conducting simulated aerial application operations.