HISTORY OF FLIGHTOn August 20, 2018, about 0645 mountain standard time, an experimental amateur built Acroduster II airplane, N787WM, was substantially damaged when it was involved in an accident in Phoenix, Arizona. The two private pilots sustained fatal injuries. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight.
The accident pilots purchased the airplane 2 days before the accident. According to the airplane's previous owner, on the day of the sale, he provided the rear seat pilot with a 2.5-hour familiarization flight. While the previous owner reported no concerns with the way the accident pilot flew the airplane, he did recommend to the accident pilot that he consider delaying his departure a day or so and fly the airplane with a flight instructor in order to become more familiar with it. The accident pilot declined the offer, stating that he didn't have time and that he felt comfortable with the airplane. That afternoon, the front and rear seat accident pilots departed to their home airport, Phoenix Deer Valley Airport (DVT), Phoenix, Arizona, about 275 nautical miles east, and arrived uneventfully.
On the morning of the accident, the pilots performed 4 uneventful takeoffs and landings in the DVT airport traffic pattern. Onboard video from the flight showed that, while turning from left downwind to left base for the fifth landing, the airplane's nose pitched up slightly just before the airplane entered the left turn onto the base leg. As the airplane continued to turn left, it appeared to exhibit aerodynamic buffeting. The airplane rolled right, then immediately rolled left as the nose pitched down and the airplane began to rapidly descend. The airplane then rolled from a 90° left bank to a 90° right bank and continued to descend in a nose-low attitude, while continuing to roll left and right, before impacting terrain. PERSONNEL INFORMATIONWhich of the pilots was manipulating the flight controls when the accident occurred could not be determined. No pilot logbooks were recovered for either pilot. AIRCRAFT INFORMATION
Records revealed that the propeller and engine were removed from the airplane on June 1, 2016, as a result of a propeller strike; at that time, the tachometer reading was 440 hours. At the time of the accident, the airplane had accumulated a total tachometer time of 471 hours. METEOROLOGICAL INFORMATIONThe 0653 weather observation at DVT included calm wind, 10 miles visibility, clear sky, temperature 31°C, dew point 16°C, and an altimeter setting of 29.90 inches of mercury. WRECKAGE AND IMPACT INFORMATIONThe accident site was located about 1/2 mile southeast of the approach end of runway 25L. The airplane came to rest upright on a magnetic heading of about 060°. The wreckage field was contained within 50 ft of the main wreckage and consisted mostly of small wing segments. The propeller assembly separated from the main wreckage.
The right-wing panels were highly fragmented. The left upper wing panel remained partially attached with impact damage to the aileron and spar. The left lower wing panel was highly fragmented from midspan to the wingtip. The empennage remained intact with damage to both elevator tips.
The engine and forward fuselage structure were crushed aft with most of the damage to the right lower side. The engine sustained impact damage to the induction and exhaust assemblies and the accessory section. The landing gear struts were twisted aft about 90°. The forward cockpit floor area was crushed upward. According to the first responders and the medical examiner, both pilots' 5-point seatbelt assemblies were secured and buckled. The fuel selector handle was found in the 'Fuel 1' (pointed left) position. According to the FAA inspector, the magneto switch was turned from the BOTH position to the OFF position by first responders.
The propeller assembly remained attached to the crankshaft propeller flange. The propeller blades exhibited twisting and chordwise scoring near the tips. One of the blade tips had separated from the blade. The spinner was crushed on one side.
Postaccident examination of the airplane and engine revealed no mechanical anomalies that would have precluded normal operation. MEDICAL AND PATHOLOGICAL INFORMATIONFront-Seat Pilot
According to the autopsy performed by the Maricopa County Office of the Medical Examiner, Phoenix, Arizona, the cause of death for the front-seat pilot was multiple blunt force injuries.
Toxicological testing performed by the FAA's Forensic Sciences Laboratory found celecoxib (a non-steroidal anti-inflammatory used to treat arthritis) and famotidine (a prescription or over-the-counter medication used to treat heartburn) in cavity blood. These two medications are generally not considered to be impairing. No ethanol was detected in cavity blood.
Rear-Seat Pilot
According to the autopsy performed by the Maricopa County Office of the Medical Examiner, the cause of death for the rear-seat pilot was multiple blunt force injuries. A contributing cause of death was atherosclerotic cardiovascular disease as documented by the presence of a metallic stent in the left anterior descending coronary artery with 75-90% occlusion distal of the stent, 100% occlusion of the right coronary artery, 50% narrowing of the left circumflex artery, and extensive scarring of the posterior wall and septum of the left ventricle. There was evidence of medical intervention including intubation. The pilot also had a well-defined meningioma and an enlarged thyroid.
Toxicological testing performed by the FAA's Forensic Sciences Laboratory identified no ethanol in the blood and salicylate and etomidate in the urine. Salicylate (commonly from aspirin) is contained in over-the-counter medications and is used to treat mild pain or to reduce the chance of blood clots. Etomidate is a general anesthetic. Glucose was detected in urine at 577 milligrams per deciliter (mg/dL) (postmortem normal is below 100 mg/dL glucose in urine) and the pilot's hemoglobin A1C was 8.8% (above 6.5% indicates diabetes).