History of Flight
On May 5, 2013, about 1930 central daylight time, an Eskildsen Steen Skybolt, registration N7KE, was substantially damaged when it impacted terrain near Easton, Minnesota. The pilot, the sole occupant, was fatally injured. The aircraft was registered to Construction Engineering Services, LLC and operated under 14 CFR Part 91 as a personal flight. Visual meteorological conditions prevailed; no flight plan was filed. The flight departed Mankato Regional Airport (MKT), Mankato, Minnesota at an unknown time.
Witnesses observed the airplane performing aerobatic maneuvers, then leveling its wings while proceeding north. About 30 to 60 seconds later, the airplane reappeared flying southbound. Witnesses heard an engine noise similar to a backfire and a reduction in power, followed by the airplane initiating a descent and a left turn. The airplane continued in a left-turning spiral descent until impact.
Personnel Information
The 44-year-old pilot held a private pilot license with single-engine land and instrument ratings. He was issued a Class 3 medical certificate on May 8, 2012, with no restrictions. No significant issues were reported during examinations. The pilot had accumulated 725 total flight hours, with 63 hours in the last 90 days.
Aircraft Information
The accident airplane received its initial experimental amateur-built certificate on June 20, 1974, and an experimental special airworthiness certificate on April 20, 1981, with indefinite expiration. Total time was 1,295 hours; last annual inspection on April 20, 2012 showed 1,277 hours. The Lycoming O-360-C1A engine (serial L-1156-36) had accumulated 2,194 total hours, with 366 hours since last major overhaul.
Wreckage and Impact Information
The airplane came to rest in a level, plowed field with no post-impact fire. No ground scars led to the site. Both left and right bi-wings sustained substantial damage. FAA personnel confirmed flight control continuity.
Engine examination at a salvage location by Lycoming Engines and the FAA showed both propeller blades bent aft slightly at mid-span. Spark plugs exhibited normal wear. Crankshaft rotation produced thumb compression on all cylinders; drive train continuity was established. Borescope inspection revealed no anomalies. Both magnetos produced spark; the left magneto's impulse coupling was weak and intermittent. The oil pickup screen was clean.
Examination of the airframe and engine revealed no evidence of mechanical malfunctions or failures that would have precluded normal operation.
Medical and Pathological Information
The pilot's first medical certificate was issued in 1988. He had undergone orthopedic surgeries but reported no ongoing problems. At last examination, height was 74 inches, weight 237 pounds (BMI 30.4), blood pressure 124/84, heart rate 68.
Autopsy at Ramsey County Medical Examiner's Office determined cause of death as multiple traumatic injuries. Significant natural disease was found: approximately 80% stenosis in the proximal left anterior descending coronary artery. Cardiac histology was normal. Toxicology tests were negative for carbon monoxide, ethanol, and tested drugs.
Family conversations indicated that over the six months before the accident, the pilot experienced at least one episode of chest discomfort and palpitations, some heartburn, and at least one episode of dizziness while performing aerobatics. His father and grandfather had suffered sudden cardiac death (father at age 42, grandfather at 52). The pilot held a third-class medical certificate, which does not require an EKG; his wife stated he never underwent cardiac tests.