What happened
On July 18, 2015, a Polaris FK14b ultralight, identified as 34-AIQ, was performing a training flight at the Bourg Cezeyriat aerodrome. The flight, intended for circuit training, involved an instructor and a student pilot. Shortly after departing from runway 18, the engine ceased producing power during the initial climb.
Witnesses observed the aircraft enter a right-hand turn at an estimated altitude of 200 feet in an attempt to turn back toward the runway. During this maneuver, the aircraft entered a stall and collided with the ground, resulting in a post-impact fire. The accident resulted in two fatalities, as both the instructor and the student died at the scene. The aircraft was destroyed.
The investigation
The investigation focused on the engine failure and the subsequent flight path. Examination of the wreckage confirmed the aircraft was in a right-hand turn at the moment of impact. While the engine showed no signs of internal mechanical failure or blockage, the propeller and hub showed damage consistent with a lack of power delivery at the time of impact. Fuel was still present in the right wing tank.
Investigators also reviewed the cockpit configuration and pilot habits. It was noted that the fuel selector on this specific aircraft is positioned behind the center console, making it less visible than the selector on the pilot's previous aircraft, a PA28. A witness reported that the pilot had struggled to start the engine earlier that morning because the fuel selector was in the closed position. Furthermore, a post-accident weight and balance check revealed that the aircraft was overloaded by approximately 40 kg at takeoff.
Findings
The primary cause of the accident was the execution of a low-altitude turn following an engine failure, which led to a loss of control. Several contributing factors were identified:
- The engine failure likely resulted from an incorrect fuel selector position, leading to a lack of fuel supply.
- The low experience of the student pilot on this specific aircraft type.
- The limited experience of the instructor in the instructor role and on ultralight aircraft.
- The excessive weight of the aircraft, which increased the stall speed.