What happened
On 10 August 2020, a Cessna 340 A, registration N413JF, was performing a private cross-country flight from Perpignan-Rivesaltes to Orléans - Saint-Denis-de-l’Hôtel. While established on final approach for runway 23, the pilot experienced a reduction in power from the left engine.
Upon noticing the aircraft could no longer maintain the approach slope, the pilot attempted a go-around by retracting the landing gear and flaps. However, the aircraft continued to descend. The pilot realized the left engine was failing when he observed a need for significant right rudder to counteract leftward yaw. Due to the low altitude, the pilot opted for a forced landing in a nearby forest rather than attempting a turn to a more suitable field, fearing a stall. The aircraft struck the tree canopy, penetrating approximately 15 meters into the vegetation before hitting the ground. A fire broke out upon impact, but the pilot and one passenger were able to evacuate the wreckage unaided. Both occupants sustained slight injuries.
The investigation
The BEA examined the wreckage and the two engines off-site. While the fire caused substantial damage to the airframe and destroyed the aircraft's logbook, investigators could not find any mechanical discrepancy between the two engines that would explain the power loss.
Investigators also analyzed the fuel system and management. Although the aircraft utilized auxiliary tanks, the investigation ruled out fuel exhaustion or selection errors as causes, noting that the pilot had switched back to the main tanks shortly before the incident. Performance calculations determined that with the landing gear down, flaps at 15°, and a windmilling propeller, the aircraft's maximum rate of climb was negative, making it impossible to maintain the approach slope or level flight.
Findings
- The primary cause of the high descent rate was the reduction in left engine power.
- The aircraft's performance was further degraded because the landing gear and flaps were still extended when the power loss occurred.
- The left propeller likely remained in a windmilling state, increasing drag.
- The pilot's ability to identify the engine failure was hindered by the low power settings used during approach, which made engine noise changes difficult to detect.
- The decision to land in the trees was driven by the low altitude and the risk of a stall during a turning maneuver.