History of Flight
On May 6, 2010, at 0546 mountain standard time, a Cessna U206G, registration N756WN, collided with terrain about 6 miles west of Yuma International Airport, Yuma, Arizona. The aircraft was operated by STP Aviation under 14 CFR Part 91. The commercial pilot was killed, and the airplane sustained substantial damage. Visual meteorological conditions prevailed, and no flight plan was filed. The flight had originated from Yuma Airport at approximately 0537.
A witness residing near the cotton field where the accident occurred reported seeing the airplane descend into the ground, followed by an explosion and fire. The witness heard the engine running but noted it did not sound like full power.
The operator stated the airplane was equipped to release sterile pink bollworm moths as part of a state-run program. The aircraft typically flew at 500 feet above ground level (agl) during these operations, which were conducted early in the morning. The pilot, the sole employee performing this task in Yuma since April, had extensive familiarity with the area. Typical flights lasted about 2.5 hours.
Flight track data from the previous three days (May 3, 4, and 5) showed a consistent pattern: departure from Yuma, westward flight, circling near the accident location, and then heading south. Radar data for the accident flight depicted a similar route. After departing at 0537, the airplane climbed to 700 feet mean sea level (msl; about 500 feet agl) and proceeded west. It then performed a left 270-degree turn, headed north at 500 feet agl, made a left-hand turn south-southwest, and traveled for 2 miles. At 0545:24, the track began a right-hand turn at 500 feet agl. After about 180 degrees of steady turn, the radius decreased and the altitude dropped to 100 feet agl, with the track twisting toward the turn center. The final radar return was at 0546:13, at 100 feet agl, near the accident site.
Personnel Information
The 27-year-old pilot held a commercial pilot certificate with single-engine and instrument ratings, issued November 13, 2008, and a first-class medical certificate issued January 4, 2010, with no limitations. His logbook was not located. On his medical application, he reported 1,551 total hours, with 150 hours in the previous 6 months. The pilot's father believed he had recently surpassed 2,000 hours, including approximately 1,500 hours in the Cessna 206, and had flown about 100 hours in the last 30 days.
Cell phone records showed that between 0517 and 0544 on May 6, 12 text/picture messages were sent from the pilot's phone to a colleague performing similar moth release work in Phoenix. The last message was sent about 2 minutes before the accident; the second-to-last just before takeoff.
Aircraft Information
The two-seat, high-wing, fixed-gear airplane, serial number U20604416, was manufactured in 1978. It was powered by a Teledyne Continental Motors IO-520-F 300-hp engine and equipped with a Hartzell constant-speed propeller (model PHC-J3YF-1RF). The aircraft was modified on June 28, 2005, with a refrigerated insect dispensing unit in the main cabin. Maintenance logs indicated an annual inspection completed on February 26, 2010, at a total airframe time of 5,581 hours. A newly overhauled engine (zero hours since major overhaul, SMOH) was installed at that time. The most recent oil change was on April 22, 2010, at 65 hours SMOH.
Meteorological Information
At 0555, the Yuma International Airport AWOS-3 reported winds from 010 degrees at 5 knots, clear skies, 10 miles visibility, temperature 19°C, dew point 3°C, and altimeter 29.77 inHg. Sunrise on May 6, 2010, near Yuma occurred at 0547, with a solar azimuth of 69.43 degrees (clockwise from true north) and an elevation of -0.77 degrees (on the horizon). Overlaying the sun's azimuth on the radar track showed that the airplane would have been turning into the sun during the final 20 seconds of radar data; altitude began to decrease as the track turned directly into and through the sun's azimuth.
Wreckage and Impact Information
The wreckage was located in a cotton field about 80 yards from a road with residential power lines and a house across the street. The wreckage path measured approximately 315 feet long on a bearing of 203 degrees magnetic. Green glass fragments were found at the initial impact point. Three distinct areas of disturbed earth led to the main wreckage: a 9-foot-long indentation with right wing tip fragments; a flattened area 21 feet long starting 13.5 feet southeast; an 18-inch circular indentation 2 inches deep; and a deep gouge extending 7.5 feet. Beyond that, debris (engine cowling, windscreen glass, wing strut, propeller) was scattered about 135 feet from initial ground contact. Burnt ground and fuel-blighted cotton plants led to the main wreckage, which consisted of the aft fuselage and tail folded over the cockpit, the left wing inverted on top of the right wing, and the engine completely separated and located 45 feet further uprange. The fuselage was heavily damaged by fire. Examination of the engine and airframe revealed no preimpact anomalies that would have precluded normal operation.
Medical and Pathological Information
An autopsy on May 8, 2010, by the Yuma County Medical Examiner attributed the cause of death to blunt force injuries sustained in the accident. Forensic toxicology by the FAA Toxicology Research Team showed no cyanide, carbon monoxide, ethanol, or detected drugs in the specimens.
Additional Information
Advisory Circular 61-134 addresses controlled flight into terrain by general aviation aircraft, noting that low-flying aircraft operating in VFR conditions, such as agricultural applicators, may encounter obstacles due to environmental factors like time of day, shadows, sun glare, and fatigue, which can lead to loss of situational awareness.