What happened
On August 31, 2008, an Avions Pierre Robin Centre Est DR 400/180 R was conducting passenger sightseeing flights at the Radolfzell-Stahringen airfield as part of an aviation event. At approximately 14:19, the pilot departed on Runway 01 with three passengers. While the aircraft initially reached an altitude of about 60 to 70 meters, witnesses observed that the plane failed to gain further altitude.
As the aircraft entered a tight left-hand turn at a very low altitude, it began to lose height. During the maneuver, the aircraft struck a group of trees, causing the right wing to separate from the fuselage. The aircraft subsequently entered an inverted position before impacting a meadow. The accident resulted in two fatalities (the pilot and the front passenger) and two injuries (the two children in the rear seats, who sustained serious and light injuries respectively).
The investigation
The BFU investigation focused on the aircraft's performance, weight, and engine configuration. Investigators examined the wreckage, which showed a destroyed cockpit, a detached nose gear, and a compressed engine. A key piece of evidence was the ignition key, which was found bent in the instrument panel.
Analysis of the ignition switch revealed that the key was set to the "left magneto" position rather than the required "both" position. Furthermore, the investigation calculated the takeoff mass to be approximately 1,033 kg, which was roughly 3% above the maximum allowable takeoff weight of 1,000 kg. The investigation also noted that the aircraft's logbook entries for the pilot's responsibility were not properly documented, as they merely referred to a main airfield logbook.
Findings
- The engine was likely started using only the left magneto, and the pilot failed to switch the ignition to the "both" position before takeoff.
- This configuration resulted in a significant reduction in engine power, preventing the aircraft from achieving full takeoff performance.
- The aircraft was operating at an overweight condition, exceeding the maximum takeoff mass by approximately 3%.
- The combination of insufficient engine power and excessive weight made it impossible for the pilot to maintain altitude during the low-altitude turn, leading to the fatal impact with trees.