What happened
On October 6, 2013, an Aerostyle Breezer ultralight aircraft departed from the Schäfershaus airfield in Handewitt, Germany. Before takeoff, the pilot informed the air traffic controller of his intention to perform an emergency procedure involving a 180-degree turn following the departure.
Shortly after taking off from runway 29, the aircraft entered a climbing phase before transitioning into level flight. Witnesses observed the aircraft initiating a left-hand turn at an altitude of approximately 70 to 80 meters. During this maneuver, the aircraft lost altitude, and the bank angle increased from 30° to approximately 60°. Witnesses reported an increase in engine noise, after which the aircraft disappeared behind a line of trees. The sound of breaking branches and a subsequent impact was heard. The aircraft struck a hollow road beneath a nearby federal highway, resulting in the destruction of the aircraft and the two fatalities of the occupants.
The investigation
The BFU investigation focused on the aircraft's weight and balance, the pilot's flight experience, and the parameters of the maneuver performed. The investigation established that the aircraft was significantly overweight. While the maximum takeoff mass (MTOM) for the Breezer is 472.5 kg, the calculated takeoff mass for this flight was 557 kg. This total included a heavy fuel load of 70 liters, the weight of both occupants (170.8 kg), and additional equipment.
The investigation also reviewed the aircraft's flight manual, which advises that 180-degree turns for engine failure simulations should only be considered above 100 meters altitude. Furthermore, the investigation examined the manufacturer's data regarding altitude loss during maneuvers. While the manufacturer noted that altitude loss during a stall in a turn could reach 100 meters, their performance testing did not account for the specific conditions of this flight, such as high bank angles or the exceeding of maximum takeoff weight.
Findings
- The aircraft was operating significantly above its maximum takeoff mass of 472.5 kg, with a total takeoff mass of 557 kg.
- The pilot performed a high-bank emergency maneuver at an altitude insufficient to maintain safety margins given the aircraft's loaded state.
- The increased weight of the aircraft likely degraded its flight performance and handling characteristics, contributing to the loss of altitude during the turn.