What happened
On July 23, 2007, at 11:25 AM, an experimental Express 2000 ER aircraft, registration HB-YMN, crashed into a residential building in the city of Basel. The flight was intended as a long-distance record attempt known as the "Lindbergh Memorial Flight," aimed at flying from Basel to Oshk려는, USA.
Following takeoff from Basel-Mulhouse airport, the aircraft struggled to gain altitude. After traveling approximately 3.8 km, the plane collided with the roof of an apartment building. Debris from the wreckage fell onto a nearby children's playground, while other parts remained embedded in the attic. The impact caused a significant fire that completely destroyed the attic space. The pilot was killed in the crash, and two bystanders sustained minor injuries. The aircraft was destroyed.
The investigation
Investigators examined the aircraft's performance capabilities, weight, and center of gravity. The aircraft was a homebuilt kit plane that had undergone modifications, including an enlarged fuel system to support long-range flight. While the kit was designed for a maximum takeoff mass of 1,542 kg, the aircraft was operated under a special permit for an overweight condition of up to 2,475 kg.
Technical analysis focused on the engine power, propeller performance, and the aircraft's weight and balance. The investigation also reviewed the certification process conducted by the Federal Office of Civil Aviation (FOCA) and the oversight provided by the Experimental Aviation of Switzerland (EAS). Evidence from radio communications, radar data, and video recordings were used to reconstruct the flight path.
Findings
The investigation established that the primary cause of the accident was the aircraft's inability to accelerate, climb, or execute a turn after takeoff. This loss of control was due to the combination of the aircraft's excessive mass, center of gravity position, and available engine performance.
Several contributing factors were identified:
- The pilot's judgment was compromised by significant time pressure and the perceived necessity to succeed in the scheduled flight.
- There was insufficient oversight and monitoring by the relevant authorities during the testing and certification phases of the aircraft.
Safety action
Following the accident, the Federal Office of Civil Aviation (FOCA) implemented several restrictive measures. It was prohibited to conduct test flights of experimental aircraft from national airports, and departures of experimental aircraft over densely populated areas from other airfields were banned. Further regulations were introduced regarding the certification of complex experimental aircraft and the requirement for a designated project manager to oversee technical and operational aspects.