History of Flight
On August 23, 2023, about 1200 mountain daylight time, an experimental amateur-built Cassutt airplane, registration N6291N, was substantially damaged when it was involved in an accident near West Jordan, Utah. The pilot was fatally injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 test flight. A witness, a pilot scheduled to race the accident airplane, reported that the accident pilot had not flown the airplane for about 2 years and had been testing it before an upcoming air race. After a flight the day before, the pilot observed oil temperature "pegged" at 280°F. On the accident day, the witness noted the engine oil pressure was about 10 psi while idling and learned the pilot had changed the oil after finding flakes in the oil screen. The witness stated the pilot seemed rushed. The witness observed the takeoff: the tail rose at about 1,000 ft into the ground run, and the airplane lifted off about 1,750 ft from the approach end. It climbed and initiated a right turn; the right wing rapidly dropped about 45° and the airplane entered a nose-down attitude, rolled wings level, then disappeared from view. Another witness saw the airplane "fall out of the sky" from about 150 ft above ground level. Surveillance video showed the airplane on a northwest heading descending from about 80 ft, maintaining a slight left-wing- and nose-low attitude until impacting a chain link fence and the ground. No data-retaining devices were recovered; no ADS-B data existed for the flight.
Aircraft Information
The pilot's wife stated he purchased the airplane around 2009 for the Reno Air Races, sold it, then reacquired it in 2013. He flew it infrequently, and had not flown it for about four months before the accident. The airplane was equipped with an experimental, air-cooled, horizontally opposed 100-hp reciprocating engine. An invoice from Polymer Dynamics, Inc. dated June 30, 2023 indicated the company coated multiple engine components. The pilot's social media showed a photographic chronology of coated parts from May 27 to August 11, 2023. Certain components exhibited coatings but the manufacturer had no record of coating them under the pilot's name. The pilot assembled the engine himself with occasional assistance. A friend who helped with an earlier engine assembly noted the pilot preferred tight clearances and discovered scuffing on a piston skirt. The friend also helped reconfigure the tail from conventional to T-tail; during flight testing they found that while in a turn, elevator effectiveness could be completely lost until acceleration, and the airplane would enter a "deadband" only overcome by accelerating. The engine manufacturer specified oil pressure at idle as 10 psi and in flight as 30-60 psi. Maintenance records were not available.
Wreckage and Impact
The airplane came to rest on a curb about 0.3 nautical miles southwest of the departure end of runway 16. All major structures were accounted for. An initial impact point was marked by a broken fence about 100 ft southeast of the main wreckage. The fuselage welded tube structure had fractured and partially separated from the engine firewall. The cabin area was breached; aft fuselage partially separated. Both wings separated and rested atop the fuselage. The T-tail empennage partially detached; elevators remained attached to horizontal stabilizers, rudder attached to vertical stabilizer. Postaccident engine examination revealed metallic fragments in the oil screen, pitting and corrosion on cylinder walls, deterioration of thermal coating on valve faces, circumferential scoring on connecting rod bearings and journals, and dark coloration and longitudinal scoring on each piston skirt.
Medical and Pathological Information
An autopsy by the Office of the Medical Examiner determined the pilot's cause of death as blunt force injuries, manner of death accident. Coronary artery disease was identified, with 75% narrowing of the left anterior descending coronary artery. Toxicological testing of femoral blood detected no tested-for substances.
Tests and Research
Two oil samples were analyzed: one from oil wash drained by the pilot and one from a jug presumed used by the pilot. Sample 2 showed high wear/age and significant particulate contamination; sample 1 showed some wear but within specification. The crankshaft, connecting rods, bearing shells, camshaft, cylinders, pistons, and wrist pins were examined. The crankshaft was intact with no fracture; main and rod journals had circumferential wear patterns corresponding to bearing shell contact. No scoring or fractures; oil passages clear. Bearing shells exhibited undersized dimensions and severe wear exposing copper layer. Scoring marks were present in combustion chambers and on pistons.