N511DSThrush Aircraft S2R-H80 · 2015

On January 16, 2015, about 1100 eastern standard time, an experimental, amateur-built Aventura II, N511DS, was substantially damaged when it impacted terrain at the Sebring Regional Airport (SEF), Sebring, Florida. Visual meteorological conditions prevailed and no flight plan was filed for the local demonstration flight. The sport pilot and student pilot-rated passenger were fatally injured. The airplane was owned by a private individual and was operated by Aero Adventure for the demonstration flight, conducted under the provisions of Title 14 Code of Federal Regulations Part 91. The flight departed at 1055.

According to local authorities, several eyewitness observed the airplane, during startup on the ramp, strike the tail of the aircraft on the concrete ramp area. A witness further reported that the pilot exited the airplane, walked to the back of the aircraft, returned to the cockpit, started the engine, and then taxied out for takeoff. No witnesses reported seeing the pilot look on the underside of the elevator or the tail of the airplane after the tail strike. According to a video taken by an eyewitness, the airplane was observed departing, climbing to about 300 feet above ground level (agl), performing a left turn, and then conducting a pass down the runway in the opposite direction. The video then shows the airplane performing a second pass, about 300 feet agl, down the length of the runway and then performing a left turn. The airplane was then observed continuing the left bank until the wings were nearly perpendicular to the ground, the nose of the airplane dropped, and the airplane was last seen in a nose down attitude descending behind the fuel tanks at the airport.

According to contract air traffic control personnel, the airplane departed, flew the traffic pattern, then flew a "low approach," climbed to about 300 feet agl, made a left turn, and then impacted the ground nose first.

According to Federal Aviation Administration (FAA) records, the pilot held a sport pilot certificate issued October 8, 2010. He did not hold, nor was he required to hold, any class medical certificate while flying a light sport aircraft. He was medically eligible to fly as a light sport pilot as long as he had a valid driver's license. At the time of this writing no record of flight hours were located.

According to FAA records, the student pilot-rated passenger was issued a second-class medical certificate on February 27, 2008. On the most recent medical application the pilot reported 11 total flight hours. Although the medical certificate had expired he would have been medically eligible to fly as a light sport pilot as long as he had a valid driver's license.

According to FAA records, the airplane, serial number AA2A0124, was issued a special airworthiness certificate on September 1, 2005 and was registered to a private individual. According to documentation provided by the previous owner, a letter of agreement and contract for purchase with Aero Adventure, dated November 20, 2014, revealed that Aero Adventure would be in possession of, and held responsible for, the airplane. No bill of sale, dated prior to the accident flight, was provided to the NTSB. The airplane was powered by a Rotax 912 ULS, 100-hp engine. It was driven by an IVO 3B-GA propeller. The airplane's most recent condition inspection was conducted on November 17, 2012 with a recorded hour meter reading of 353.1, the hour meter reading found in the wreckage indicated 362.52 hours.

The fuselage of the airplane consisted of a fiberglass hull with seating provisions for two occupants. Pontoons were located at the outboard portion of each wing, retractable main landing gear were attached to the fuselage, and a steerable tail wheel was attached to the empennage.

The airplane was formerly equipped with a Ballistic Recovery Parachute (BRS) system; however, at some point prior to the accident, the BRS system was removed. Examination of the maintenance records did not reveal any logbook entries of the BRS system being removed nor of any recalculation of the basic operating weight and center of gravity (CG) position. Although an accurate CG could not be determined, utilizing the aircraft empty weight, located in the airframe maintenance record, dated August 30, 2005, the pilot and student pilot-rated passenger weights acquired during the autopsy, and considering a full tank of fuel. The aircraft, at the time of takeoff, would have been below the maximum allowable takeoff weight.

The airport was a publically-owned airport and at the time of the accident had an operating contract control tower, due to the airshow that was taking place at the time; however, normal operations at this airport would not have utilized an operating control tower. The airport was equipped with two runways designated as runway 1/19 and 14/32. The runways were reported as "in good condition" at the time of the accident. Runway 1/19 was a 5,234-foot-long by 100-foot-wide runway and runway 14/32 was a 4,990-foot-long by 100-foot-wide. The airport was 62 feet above mean sea level.

The 1059 recorded weather observation at SEF included wind recorded as calm; however, according to personnel associated with the airport the Automatic Weather Observation System was reported out of service due to the wind indicator. It also recorded broken clouds at 10,000 feet agl, 10 miles visibility, temperature 17 degrees C, dew point 13 degrees C, and barometric altimeter 30.14 inches of mercury. According to written statement by contract personnel working in the temporarily-manned tower, the wind was from 360 degrees at 13 knots.

According to local authorities, eyewitness reports, and an eyewitness video recording, the airplane was performing a "fly-by" when the airplane pitched up, rolled to the left, and nosed down, impacting the ground. The airplane impacted the ground in a near vertical position. An eyewitness, who was also a mechanic, reported audibly observing the engine "cut out or reduced power" just prior to the nose down decent. Another eyewitness reported that the "tail appeared to flutter."

The airplane impacted the ground just prior to the arrival end of runway 14, about 150 yards from the airport's fuel storage farm. The debris path was compact and only a single ground scar was noted where the airplane impacted and another smaller ground scar was located where the engine came to rest. The airplane exhibited various degrees of impact and crush damage. Flight control continuity was confirmed from the cockpit control to the respective flight control surface. However, the left side elevator, as viewed from behind the airplane, was noted as indicating about 15 degrees trailing edge down and the elevator trim was noted as fully deflected, trailing edge down. The right side elevator, as viewed from behind the airplane, was noted as in the neutral position. Examination of the elevator torque bar revealed the left side elevator torque bar exhibited numerous bends in both the positive direction on the forward top channel flange and in the negative direction on the aft bottom channel flange. The trim tab cable was also found separated from the cable eyelet and extensive corrosion was noted on the eyelet and cable. Several support cables exhibited tensile overload.

The engine, mounted above and aft of the cabin, was separated from the airplane by local authorities, to facilitate recovery The propeller remained attached to the engine; however, two of three propeller blades were impact-separated about 5 inches from the propeller hub, and the other propeller blade exhibited some indication of rotation, slight rotational scoring, and exhibited leading edge damage. Fluid was evident throughout the engine that appeared similar in color and smell as automotive gasoline (autogas). Both carburetors were removed and contained various amounts of fluid that were similar in color and smell as autogas. The cylinder No. 1 and 3 carburetor float bowl gasket was pinched; however, the pinch did not appear to impede flow nor was there any evidence of leaking.

The fuel pump was removed and a fuel sample was extracted from the unit. The fuel sample was free of debris and consistent in smell and color as autogas. The pump plunger was actuated by hand, operated normally, and no mechanical abnormalities or malfunctions were noted. Fluid, similar in smell and color as autogas, was noted as exiting through the outlet fitting during manual operation.

The harness leads on one engine coil were impact damaged; however, all spark leads remained attached to their associated spark plugs. One ignition trigger coil was impact damaged and displaced from its mount.

The engine rocker box covers were removed and examined with no abnormalities noted. The engine was rotated by hand utilizing the propeller hub and thumb compression was confirmed on all four cylinders. The intake and exhaust valves all operated smoothly and normally.

The engine was mounted on a pallet and forklift and connected to a battery. The engine started and operated at various power settings with no hesitations noted. Although, due to the one engine coil being damaged, two of the spark plugs would not have been operating; however, the remaining spark plugs appeared to operate as expected.

Both hydraulic shutoff valves, located between the two seats, were both found in the "ON" position.

An autopsy was performed on the pilot, on January 19, 2015, by the Office of the District Medical Examiner, Winter Haven, Florida. The cause of death was reported as "Blunt Impact to Head and Torso" and the report listed the specific injuries.

The FAA's Bioaeronautical Sciences Research Laboratory, Oklahoma City, Oklahoma, performed toxicological testing on the pilot. The toxicology report stated no ethanol was detected in urine. The report stated Salicylate and Zolpidem were detected in the urine and Zolpidem was also detected in cavity blood. However, the level of Zolpidem was below the testing calibration curve and below the therapeutic level for the medication. According to the FAA Aerospace Medical Research website the therapeutic low for Zolpidem was 0.0250 ug/mL.

An autopsy was performed on the student pilot-rated passenger, on January 19, 2015, by the Office of the District Medical Examiner, Winter Haven, Florida. The cause of death was reported as "Blunt Impact" and the report listed the specific injuries.

The FAA's Bioaeronautical Sciences Research Laboratory, Oklahoma City, Oklahoma, performed toxicological testing on the student pilot-rated passenger. The toxicology reported stated no ethanol was detected in urine. The report stated Ibuprofen was detected in the urine.

The elevator horn assembly and a section of elevator trim cable were sent to the NTSB Materials Laboratory for further examination. The elevator horn was intact and the left elevator attachment channel exhibited deformation in the positive direction on the upper flange of the channel and deformation in the negative direction on the aft portion of the lower flange. The deformations were forward and aft respectively of the elevator attachment bolt. The deformations were consistent with the elevator pivoting rear downward about the attachment bolt.

The elevator trim cable consisted of a solid inner cable encased in a cable sheath; the cable exhibited a forward bend. The cable, when in the extended position, exhibited a longitudinal wear area forward of, and extending into, the bend. The inner diameter of the sheath also exhibited a wear mark similar in shape and dimension of the inner wire. The wear had penetrated the plastic inner sheath liner. The wear on the wire and sheath were consistent with side loading of the cable. For further information on the examination of the elevator horn and elevator trim cable see the "Materials Laboratory Report" located in the docket associated with this accident.