What happened
During a flight to a fly-in event in a different state, a biplane carrying a pilot and a pilot-rated passenger crashed into the ground. Witnesses observed the aircraft flying at a low altitude and low airspeed over a frozen lake. The aircraft was seen oscillating from side to side before initiating a left turn, after which it was seen nose-diving into the terrain. The impact resulted in a post-impact fire that destroyed much of the wreckage. Analysis of the debris confirmed the aircraft struck the ground in a nose-down orientation.
Environmental conditions at the time of the accident involved significant wind activity. While reports from various weather stations were inconsistent, data from a station 11 miles south of the site indicated westerly winds of 11 knots with gusts reaching 2-7 knots. Evidence at the crash site, specifically a burnt area extending east from the impact point, suggested winds were blowing from the west. The aircraft was not configured for landing on ice, despite witness speculation regarding the pilot's intentions.
Findings
Investigation of the airframe, engine, and control systems showed no evidence of mechanical failure or pre-impact anomalies. Based on the wreckage damage and witness accounts, it is believed the aircraft entered an aerodynamic stall/spin because the airspeed dropped below the critical angle of attack.
- The pilot's blood contained chlorpheniramine, a sedating antihistamine, at therapeutic levels.
- The effects of this medication can impair psychomotor functions, visual-spatial cognition, and motor coordination.
- The presence of this sedative likely impaired the pilot's ability to maintain control of the aircraft while maneuvering at low altitudes in strong, gusty wind conditions.