Amateur-built EVOLUTION N515DL accident near Mcdermott, Ohio

Probable cause

The pilot’s failure to recognize and avoid airframe icing conditions, which resulted in a loss of airplane performance and a subsequent loss of control and in-flight break-up.

NTSB analysis

The pilot departed on a cross-country flight and climbed the airplane to a cruise altitude of 25,000 ft mean sea level (msl). The airplane encountered an area of moderate icing and decelerated to near its stall speed. It then entered a rapid left turning descent. Sections of the right wing and tail separated in flight, and the airplane impacted terrain in a near-vertical attitude. A postimpact fire ensued, and the airplane was destroyed.

Examination revealed that the in-flight separations of the wing and tail sections were consistent with overstress, and no pre-accident mechanical anomalies were observed that would have precluded normal operation. Although toxicological testing detected ethanol in the pilot’s muscle and liver, the ethanol was likely not from alcohol consumption based on tissue concentrations and the absence of ethanol in urine.

Review of forecasted weather information indicated that the pilot was likely operating in instrument meteorological and icing conditions for about 20 minutes before the accident, with the potential for supercooled large droplets along the flightpath and structural icing at the airplane’s cruise altitude. There was no indication that the pilot obtained a weather briefing from an access-controlled source before the accident, and his awareness of the icing conditions was not determined. The airplane was not equipped for flight in icing conditions.

Based on the available information, the pilot failed to recognize and avoid icing conditions during cruise flight, which resulted in a loss of airplane performance, an aerodynamic stall, and a subsequent loss of airplane control followed by an in-flight break-up.

Text from the NTSB. Open the NTSB docket for CEN21FA238 for the full record.