What happened
On November 7, 1996, a Cessna 421 C (registration HB-LRX) departed from Geneva Cointrin Airport, Switzerland, bound for Bordeaux Mérignac, France. The flight was operating under IFR conditions with one pilot and seven passengers on board. After reaching a cruising altitude of 20,000 feet, the aircraft began its descent toward its destination.
At approximately 09:03 UTC, the pilot reported an engine failure affecting the right engine. While the pilot initially attempted to continue the flight toward Bordeaux, several unsuccessful attempts to restart the engine were made. During this period, the aircraft experienced a continuous loss of altitude. The pilot requested a diversion to Limoges, but the situation deteriorated as the pilot reported that the propeller was stuck and could not be placed in the feathered position.
As the aircraft continued to descend, the pilot struggled to maintain even 3,500 feet. By 09:26 UTC, the pilot reported being below the cloud layer and below terrain, stating they could barely maintain 2,500 feet. Shortly after, radar contact was lost. At 09:29 UTC, the aircraft struck a field at "La Naute" near Donzeil, France, and an immediate post-impact fire occurred. All eight fatalities were confirmed.
The investigation
The investigation focused on the technical failure of the right engine and the subsequent inability to control the aircraft's descent. Investigators examined the wreckage, the engine components, and the propeller mechanism. The investigation specifically looked into the maintenance history of the crankshafts and the operational status of the propeller regulation system. Radio communications between the pilot and air traffic control were also analyzed to reconstruct the final minutes of the flight.