Accident Overview
On August 8, 2010, at approximately 0958 Pacific daylight time, a HOAC-Austria (now Diamond) HK-36R Super Dimona motorglider, registration N40440, sustained substantial damage when it struck a building at Bend Municipal Airport (BDN) in Bend, Oregon. The pilot, who was the sole occupant and owner of the aircraft, received fatal injuries. The flight was conducted under Part 91 of the Federal Aviation Regulations in visual meteorological conditions. No flight plan was filed.
Flight History
Witnesses reported that the aircraft departed from runway 16, climbed to a low altitude, and then turned left, apparently attempting to re-enter the traffic pattern for landing. One witness stated the airplane never exceeded 50 feet in altitude; another observed the left wing dip just before impact. The airplane collided with an unoccupied factory building near the southeast corner of the airport. It came to rest upright on the ground outside the building, adjacent to a south-facing wall. The canopy was shattered, but the pilot remained in the cockpit. No fire occurred.
Pilot Information
According to FAA records, the pilot held a private pilot certificate with ratings for airplane single-engine land, single-engine sea, multiengine land, and instrument. His most recent third-class medical certificate was issued in June 2009, and he reported 5,000 total flight hours. The Oregon State Police Medical Examiner determined the cause of death as blunt force injuries. Toxicology tests found no carbon monoxide, cyanide, ethanol, or screened drugs. FAA records indicated a previous runway excursion in the same aircraft in 2004, with no injuries or damage.
Aircraft Information
The aircraft was a powered sailplane manufactured in 1993, registered to the pilot in 2001. It was equipped with a Rotax 912 A2 80 hp engine and a two-blade variable-pitch MT propeller that could be fully feathered. The aircraft was of glass fiber composite construction with fixed conventional landing gear. The fuel tank, located behind the seats, had a capacity of 21.1 gallons (20.9 usable). No maintenance records were located.
Meteorological and Airport Information
At 0955, the automated weather observation at BDN reported winds from 260° at 3 knots, clear skies, temperature 19°C, dew point 9°C, and altimeter 30.00 inches of mercury. The airport elevation is 3,640 feet. Runway 16/34 measures 5,200 by 75 feet. No air traffic control tower was present, and no communications were recorded.
Wreckage and Impact Examination
The first impact mark was on a south-facing wall at a southwest corner, with crush damage about 8 feet above ground. Red paint transfer was found on the right wing leading edge. The fuselage remained intact; the horizontal stabilizer separated from the vertical stabilizer. Both wings were significantly damaged, the left wing twisted over the fuselage. The engine remained attached, and the propeller blades were splintered. The fuel selector was in the ON position, the propeller pitch control set to about 2,500 rpm, and the mode switch to AUTO. Cockpit trim was set to full nose-up. The propeller control circuit breaker was in the activated (out) position, disabling that circuit.
Detailed examination revealed no pre-existing mechanical failures in the flight controls or engine. The engine was started and run to 1,200 rpm with no anomalies. Both propeller blades were set to a takeoff pitch and showed signs of powered rotation at impact.
Additional Findings
A carburetor icing chart indicated that conditions at the time were conducive to serious icing at glide power. The airspeed indicator exhibited a sticking needle at 30 knots, and the tachometer read approximately 15% low compared to input. The propeller control circuit breaker functioned normally when tested. Several service bulletins were not complied with, including one requiring updated carburetor flanges and another for a revised start check placard.
An insect nest found in the left fresh air vent was identified as a young paper wasp nest, likely from the Polistes genus. The curator noted the nest was weathered and contained no brood, but could have housed one or two wasps. The possibility of a startled wasp causing a distraction could not be ruled out.
No probable cause was determined by the investigation.