Incident Overview
On May 10, 2001, at approximately 12:53 local time, a Jodel D-117 with registration HB-SUL crashed into a meadow east of the municipality of Aristau in the canton of Aargau, Switzerland. The accident occurred during a training flight intended to revalidate the pilot's class rating. The aircraft was destroyed, and the pilot sustained fatal injuries, while the flight instructor survived.
Flight Details and Sequence of Events
The pilot and instructor departed from Birrfeld airfield shortly before 13:00. They climbed to approximately 3,000 feet MSL near Bremgarten, where the instructor simulated an engine failure by reducing throttle. The pilot was tasked with managing the descent for an emergency landing. During the approach, communication between the two crew members was limited. The instructor observed that the pilot appeared tense and did not verbally confirm intentions regarding the landing site.
As the aircraft descended to low altitude, the instructor prepared to issue a go-around command. At that moment, the pilot unexpectedly initiated a left turn. The aircraft overflew a tree at an estimated height of 20–30 meters before crashing into the ground in a left-downward motion. Witnesses reported hearing the engine rev briefly prior to impact.
Investigation Findings
The Swiss Federal Accident Investigation Board (BFU) determined that the accident was caused by a loss of control at low altitude following an inappropriate emergency landing exercise. The instructor was surprised by the pilot's sudden left turn and could not take effective countermeasures. Contributing factors included a lack of communication between the pilot and instructor, gaps in the emergency landing procedure system, and the instructor's delayed decision to abort the exercise.
Casualties and Damage
The pilot, a Swiss citizen born in 1938 with approximately 1,200 flight hours, died later that evening at University Hospital Zurich. The instructor, a Swiss citizen born in 1975, survived with injuries. The aircraft was destroyed, and minor damage to the surrounding field was reported.