Amateur-built BD 4 N11DV accident near Dayton, Nevada

Probable cause

The pilot’s failure to maintain adequate airspeed and his exceedance of the airplane’s critical angle-of-attack during the turn onto the final base leg in gusting wind conditions, which resulted in a stall/spin at too low an altitude to allow recovery.

NTSB analysis

The airline transport pilot was conducting a personal cross-country flight. The pilot had flown the airplane for over 1 hour, including a fuel stop and an instrument approach, before returning to his home airport. During this time, the airplane's owner/builder, who was also a pilot, was in radio contact with the pilot. He reported that the pilot called downwind for landing and then left base to final. The pilot did not report any problems with the airplane; he said that it was flying beautifully and that all of the instruments were in the normal range. The owner and another witness reported that, as the pilot transmitted that he was turning onto the final base leg for landing, they saw the airplane enter a spin before it hit the ground. The owner reported that the wind was from 250 degrees at 12 knots gusting to 15 knots. A weather report from an airport 9 nautical miles southwest of the accident airport reported similar conditions. An examination of the wreckage did not reveal any anomalies that would have precluded normal operation.

Toxicology testing of the pilot detected fexofenadine, a nonsedating allergy medicine, in his urine but not in his blood; therefore, the medication would not have been causing systemic effects at the time of the accident. The autopsy identified an enlarged heart with moderate-to-severe atherosclerosis of all of the main coronary arteries but no evidence of heart muscle damage. Although the coronary artery disease would have increased the pilot's risk of impairment, the investigation found no evidence that he had experienced prior symptoms and could not determine if the disease caused the pilot symptoms during the flight or contributed to the accident. It is likely that the pilot did not maintain adequate airspeed during the turn onto the final base leg in gusting wind conditions and exceeded the airplane's critical angle-of-attack, which resulted in an aerodynamic stall/spin.

Text from the NTSB. Open the NTSB docket for WPR14LA222 for the full record.