What happened
On May 31, 1964, a De Havilland DH-82 Tiger Moth, registration HB-UBH, was performing a glider tow operation at the Courtelary aerodrome. The flight was intended to tow a Mucha HB-614 glider. During the takeoff roll, approximately 100 meters after applying full power, the aircraft encountered a sudden and powerful lateral gust from the south. This wind shift pushed the aircraft toward a nearby hangar.
In an attempt to maintain the runway centerline, the pilot banked the aircraft to the left, which caused the left wing to approach the ground. To mitigate the developing crisis, the pilot released the glider and attempted to continue the takeoff. However, the aircraft's path intersected with an L-Spatz 55 glider parked at the edge of the field. The Tiger Moth's landing gear struck the stationary glider, causing the pilot to lose control. The aircraft tilted sharply to the left and performed a heavy landing in an adjacent wheat field.
The investigation
The investigation examined the meteorological conditions at the time of the accident, noting that while the day began clearly, storm activity was approaching. The wind had recently shifted from a northerly breeze to a westerly direction. Investigators also reviewed the pilot's actions during the critical moments of the takeoff roll and the mechanical state of the aircraft.
Findings
- A sudden change in wind direction caused the towing aircraft to be pushed off its intended course.
- The pilot failed to maintain the aircraft's alignment with the runway following the gust.
- The pilot delayed the release of the glider for too long, failing to realize the collision course with the parked aircraft in time.
- The collision with the stationary glider resulted in a loss of control and the subsequent heavy landing.
There were no injuries to the pilot or any other persons during the event.