N586BNNelson William F RANS S-12 · 2007

On April 3, 2012, about 0742 mountain standard time, a Nelson Rans S-12, N586BN, impacted terrain shortly after takeoff from Falcon Field Airport (FFZ)Mesa, Arizona. The commercial pilot and the passenger/owner were fatally injured. The airplane was substantially damaged. The airplane was registered to the passenger and operated by the pilot. Visual meteorological conditions prevailed and no flight plan was filed for the local personal flight.

Witnesses reported that shortly after the airplane took off, when it was about 200-300 feet above ground level, the airplane made a sudden right turn of about 90 degrees. Some witnesses reported that there was a reduction in engine power just prior to the right turn and an increase in engine power during the turn. Witnesses reported that while in the turn, the airplane appeared to stall and start to spin; one witness reported that it appeared as if the pilot started to regain control just prior to impacting terrain.

At the time of the accident, the pilot, age 23, held a commercial pilot certificate with airplane single- and multi- engine land and instrument ratings. His most recent certificate was issued on March 22, 2012. His most recent Federal Aviation Administration (FAA) second-class medical certificate was issued on May 11, 2011 with the restriction that he must wear corrective lenses. The pilot had accumulated about 734 hours of flight experience, 121 of which were in the accident airplane. The pilot had been flying the accident airplane since July of 2010.

The airplane was an amateur built experimental Nelson Rans S-12, serial number 119147, which was privately built in 2007. The airplane was equipped with a Rotax 912 ULS 100 horsepower engine in the pusher configuration. The airframe and engine maintenance logbooks were not located.

During a postaccident telephone conversation, the builder of the airplane reported that when he built the airplane, the fuel system consisted of four fuel tanks, two outboard auxiliary fuel tanks and two inboard main fuel tanks. The fuel selector valve, which consisted of four positions: ‘main’, ‘aux’, ‘both’, ‘off’, was located between the pilot and passenger seats. The builder reported that with the configuration of the fuel system, it is possible that, if the fuel selector valve was in the ‘off’ position, the airplane would have enough residual fuel within the system to operate the airplane normally until about initial climb.

At 0747, the weather reporting station located at FFZ reported wind 030 degrees at 5 knots, 40 statute miles of visibility, clear skies, temperature 13 degrees Celsius (C), dewpoint -9 degrees C, and an altimeter setting of 29.98 inches of mercury. The accident airport elevation was 1,394 feet. Based on the recorded weather data, the corresponding density altitude was about 1,432 feet.

According to the FAA carburetor icing probability chart, with the recorded temperature and dew point, the airplane was unlikely to experience carburetor icing at climb, cruise, and glide power.

An on-scene examination conducted by representatives from the FAA revealed that the airplane impacted the ground in a nose low attitude and started to burn. All three propeller blades were still attached at the hub, however, the blades were separated about 6 inches outboard of the hub. One of the propeller blades was located in an earthen wall located next to the main wreckage, and two of the blades were found about 250 feet from the main wreckage. All main components of the airplane were present, and control continuity was established throughout. The parachute was deployed, but resting unopened directly behind the main wreckage. The parachute T-handle was located and the pin to secure the handle was still in place. The end of the cable from the T-handle to the igniter was broomstrawed. The smell of automotive gasoline was noted underneath the airplane, most notably underneath the carburetors; fuel was found in one of the carburetor bowls. The fuel selector valve was unable to be positively identified. The engine was rotated by hand and rotated through all four compression strokes; during the rotation, the engine felt “gritty” on the inside.

The Maricopa County Medical Examiner completed autopsies on the pilot and passenger; cause of death was reported as blunt force injuries.

The FAA Civil Aerospace Medical Institute (CAMI) conducted forensic toxicology examinations on specimens from the pilot, and reported that no ethanol or any screened drugs were detected. Testing for carbon monoxide and cyanide were not completed.

During a postaccident examination of the airframe and engine, control continuity was established throughout. The flap handle was identified loose within the wreckage; the flap position was unable to be determined. The fuel selector valve was not found. The instrument panel sustained impact and fire damage; the turn coordinator showed a turn to the right.

The engine was examined and the exhaust system was mounted on top of the engine close to a fuel line, fuel system transducer, coolant, and ignition systems. Fire damage was noted to the magneto side (forward side, opposite of the propeller) of the engine. The top spark plugs were removed and identified as having appropriate gapping determined by the engine manufacturer. The valve covers were removed and oil was present within the system. The engine was rotated via the propeller; all valves produced the same amount of lift and thumb compression was obtained on all cylinders. The engine was borescoped and no anomalies were noted. The water pump and oil pump were removed and no anomalies were noted. The fuel pump was removed and functioned normally when activated by hand, no fuel was present.

There was no evidence of preimpact anomalies that would have resulted in a loss of engine power. Due to damage, continuity of the fuel and ignition systems could not be ascertained.