Fatal Spin Accident Involving Wega 100 Test Flight

Casualties unknown • Obermehler, DE

A test flight of a Wega 100 aircraft ended in a fatal spin accident near Obermehler, Germany, after the pilot attempted to test stall characteristics with extended flaps.

What happened

On September 18, 2001, a H. K. Aircraft Technologie AG/Wega 100 departed from the Obermehler airfield for a flight test. The purpose of the flight was to evaluate the aircraft's stall behavior using an extended flap setting, specifically increasing the flap position from 40° to 50° to achieve a target stall speed of 45 knots.

While flying at an altitude of approximately 2,500 ft (NN), the aircraft suddenly banked to the left and entered a spin. Eyewitnesses observed the aircraft performing three rotations before transitioning into a steep, flat spin. The aircraft subsequently impacted the ground approximately 300 meters northwest of the runway threshold at 16:09 local time. The impact and subsequent post-crash fire resulted in the fatal injury of the pilot and the total destruction of the aircraft. There was minor damage to the surrounding terrain.

The investigation

The BFU investigation examined the aircraft's configuration, weight and balance, and the flight conditions. Investigators found that the flap actuator had been manually adjusted prior to takeoff to allow the 50° extension. Although the aircraft's control linkages were intact, the connection elements were not free-moving.

Analysis of the weight and balance revealed that the aircraft's takeoff weight was approximately 681 kg, which exceeded the maximum allowable takeoff weight of 640 kg by 41 kg. The center of gravity was measured at 0.953 meters, which remained within the permissible longitudinal range (0.79 m to 0.99 m).

Findings

  • The aircraft entered a spin because the pilot likely flew below the minimum stall speed while attempting to test the new flap configuration.
  • The pilot was unable to recover from the resulting unintentional spin.
  • The aircraft was operating in an overweight condition, exceeding the maximum takeoff weight by 41 kg.
  • The flight was conducted at an altitude (between 2,500 and 4,000 ft) that was considered insufficiently high for such testing, as a higher altitude (7,000 to 8,000 ft) would have provided a safer margin for recovery.

Probable cause

The accident was caused by the pilot's inability to recover from an unintentional spin that occurred after the aircraft's airspeed dropped below the minimum stall speed during a flap configuration test.

Frequently asked questions

What happened in the 2001-09-18 aircraft accident near Obermehler, DE?

A test flight of a Wega 100 aircraft ended in a fatal spin accident near Obermehler, Germany, after the pilot attempted to test stall characteristics with extended flaps.

What aircraft was involved and where did it happen?

The accident on 2001-09-18 involved a aircraft, at Obermehler, DE.

What was the probable cause of the accident?

The accident was caused by the pilot's inability to recover from an unintentional spin that occurred after the aircraft's airspeed dropped below the minimum stall speed during a flap configuration test.

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