What happened
On Monday, March 31, 1997, at 11:45, a ULM DTA Dynamic 503 (identified as 42-ET) was performing a local flight at the Mably ultralight airfield. While attempting to land on runway 34, the pilot encountered a sudden gust of wind at an altitude of approximately 5 to 10 meters above the ground. In response to this wind gust, the pilot initiated a go-around procedure.
During the maneuver, the aircraft drifted to the left side of the airfield. Believing the aircraft had sufficient altitude to clear the trees bordering the runway, the pilot did not correct this lateral drift. Consequently, the wing struck the tops of the trees, causing the aircraft to roll inverted and crash into an adjacent field. The impact resulted in the destruction of the aircraft and one injury to the pilot.
The investigation
Investigators examined the airfield configuration and the meteorological conditions at the time of the accident. The investigation established that the runway is flanked by hedges and trees approximately 20 meters high, located 25 meters to the left and 40 meters to the right of the runway edges. Additionally, a plantation of trees is situated roughly 80 meters from the threshold of runway 34. The investigators determined that this specific arrangement of vegetation is highly likely to cause significant wind turbulence in the lower altitudes.
Findings
- The primary cause of the accident was the pilot's insufficient perception of the environment, specifically regarding the lateral drift and the proximity of obstacles during the go-around.
- The presence of surrounding trees and hedges created turbulent wind conditions near the ground.
- The pilot's decision to proceed with the maneuver without correcting the leftward drift led to the collision with the treetops.