N756WNCessna U206G · 1978

On May 6, 2010, at 0546 mountain standard time, a Cessna U206G, N756WN, collided with terrain 6 miles west of the Yuma International Airport, Yuma, Arizona. The airplane was operated by STP Aviation under the provisions of Title 14 Code of Federal Regulations, Part 91. The commercial pilot was killed, and the airplane was substantially damaged. Visual meteorological conditions prevailed, and no flight plan had been filed. The flight originated at the Yuma airport about 0537.

A witness, who lives in a house across from the cotton field where the accident occurred, stated that he was picking squash when he looked up and saw the airplane descend into the ground, which was followed by an explosion and fire. He heard the engine running, but thought that it was not running at full power.

The operator stated that the airplane was equipped to release sterile pink bollworm moths as part of a program run by the State of Arizona. The plane normally flies at 500 feet above ground level (agl) when releasing the moths. The operation is done early in the morning, before the heat of the day, so the insects can find protection from the sun before it gets too hot. The pilot’s assignment on the day of the accident was to release insects over all the designated fields in the Yuma area. The pilot was the sole employee doing this in Yuma and had been there since April. He was very familiar with the area and the fields he worked. A typical flight would last about 2.5 hours.

The operator provided flight track data for flights the pilot conducted on May 3, 4, and 5, which departed the Yuma airport to release pink bollworm moths on the same designated fields that were assigned on the day of the accident. The flight track data was collected by a GPS enabled Ag-Nav navigation computer that was mounted in the cockpit of the accident airplane. During all three flights, the airplane departed Yuma Airport, proceeded west, circled two fields in the vicinity of the accident location, and proceeded south. These three flights were consistent with the radar track for the accident flight. The radar data of the accident flight depicts the airplane departing Yuma Airport at 0537, climbing to 700 feet mean sea level (msl) (500 feet agl), and proceeding west about 5 miles; it performed a left 270-degree turn, stopped the turn heading north at 500 feet agl, made a left-hand turn to the south-southwest and proceeded for 2 miles. At 0545:24, the track starts a right-hand turn at 500 feet agl, after about 180 degrees of a steady turn, the radius of the turn begins to decrease, and the track twists toward the center point of the turn as the altitude decreases to 100 feet agl. The final radar return is at 0546:13, 100 feet agl, in the vicinity of the accident site.

The pilot, age 27, held a commercial pilot certificate with ratings for airplane single-engine land, airplane land, and instrument airplane issued November 13, 2008, and a first-class medical certificate issued January 4, 2010, with no limitations. The pilot’s logbook was not located and was not examined. On the pilot’s January 4, 2010, first-class medical application he reported having 1,551 hours, with 150 hours accumulated in the previous 6 months. The pilot’s father stated that he believed his son had just recently passed the 2,000 hour mark, with about 1,500 hours of that in the Cessna 206, and he had probably flown about 100 hours in the last 30 days.

A review of the pilot’s cell phone records revealed that on May 6, 2010, between 0517 and 0544, 12 text/SMS/picture messages were sent from the pilot’s phone to a phone number that belongs to a colleague pilot who was doing the same moth release work in the Phoenix area. The last message was sent about 2 minutes before the accident, and the second to last message was sent just before the pilot tookoff.

The two-seat, high-wing, fixed-gear airplane, serial number (S/N) 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 airplane had been modified on June 28, 2005, with the installation of a refrigerated insect dispensing unit positioned in the main cabin. Review of copies of the maintenance logbook records showed an annual inspection was completed on February, 26, 2010, at airframe total time of 5,581 hours, and a newly overhauled engine was installed (zero hours SMOH). The engine logbook indicated that the most recent oil change was performed on April 22, 2010, at 65 hours since major overhaul (SMOH).

Weather conditions recorded by the Yuma International Airport AWOS-3 (Automated Weather Observation System) at 0555 were winds from 010 degrees at 5 knots; sky clear, 10 miles visibility; temperature 19 C; dew point 3 C; and altimeter 29.77 inHg.

Utilizing the National Oceanographic and Atmospheric Administration (NOAA) sunrise/sunset calculator and solar position calculator, the time of sunrise on May 6, 2010, in the vicinity of Yuma was 0547. The sun’s azimuth at 0547 was 69.43 degrees, measured clockwise from true north, and the elevation was -0.77 degrees (on the horizon). Overlaying the sun’s azimuth line over the radar track illustrated that the airplane would have been turning into the sun’s azimuth during the final 20 seconds of radar data. Additionally, the airplane’s altitude depicted in the radar data starts to decrease as the track turns directly into and through the sun’s azimuth.

The wreckage was located in a cotton field about 80 yards from a road that had residential power lines along it, and a house across the street. The wreckage path is approximately 315 feet long, on a bearing of 203 degrees magnetic. Green glass fragments were located at the initial impact point. Three distinct areas of disturbed earth led up to the main wreckage. The first section was an indentation 9 feet in length that contained fragments from the right wing tip; the second section of disturbed earth started at the end of the first section but 13.5 feet to the southeast that was a much flatted earth area that extended for 21 feet. Following this section was an 18-inch circular indentation about 2 inches deep. Next in line and 13.5 feet further to the southeast was a deep gouge extending for 7.5 feet. The debris field became more substantial beyond this point; pieces of engine cowling, windscreen glass, ring wing lift strut, and propeller, were located approximately 135 feet from the initial ground contact. The burnt ground and cotton plants exhibiting damage consistent with fuel blight, lead up to the main wreckage. The main wreckage consisted of the aft fuselage and tail folded over the cockpit, the left wing was inverted and stacked on top of the right wing, the engine was completely separated from the engine mount, and was 45 feet further up range of the main wreckage. The fuselage had been exposed to extreme thermal energy, which destroyed most of the cockpit, aft fuselage, and a portion of the tail. Examination of the engine and airframe did not reveal anything that would preclude the normal operation of the engine or flight controls.

An autopsy was performed on the pilot May 8, 2010, by the Yuma County Medical Examiner. The cause of death was attributed to blunt force injuries sustained in an aircraft accident.

Forensic toxicology was performed on specimens from the pilot by the FAA Forensic Toxicology Research Team CAMI, Oklahoma City, Oklahoma. The toxicology report stated no cyanide detected in blood, no carbon monoxide detected in blood, no ethanol detected in vitreous, and none of the listed drugs were detected in the liver.

Advisory Circular 61-134 addresses controlled flight into terrain by general aviation aircraft, states the following, “LOW-FLYING AIRCRAFT OPERATING IN VFR CONDITIONS. Although many of the factors listed previously apply to low-flying aircraft operating in VFR conditions, this is a special category for those pilots flying below minimum safe altitudes. Such operators include agriculture applicators and helicopter pilots who routinely operate near trees, telephone lines and power lines, or other such obstacles. In many cases, the pilot was aware of the obstacles but environmental factors such as time of day, minimal light, shadows, darkness, sun glare, cockpit blind spots, fatigue, or other such factors resulted in the pilot losing situational awareness and hitting an obstacle or impacting the ground.”