What happened
On 7 May 2019, an AEROS SKYRANGER, registration 13LZ, was performing cross-country flights between the village of Saint-Antonin-sur-Bayon and the Sainte-Victoire mountain in France. Witnesses observed the aircraft performing several out-and-back maneuvers, flying parallel to the mountain face at an altitude below the peak. During the final leg, the aircraft flew at a lower altitude than previous passes before turning north toward the mountain.
Shortly before the impact, the pilot transmitted five radio messages over the Aix-Les-Milles control tower frequency, the first of which reported control problems. Following this, the aircraft banked left and continued on a straight path toward the terrain. A witness's video recording showed the aircraft at full throttle, banking approximately 30 degrees, before it struck the rocky face of the mountain roughly 20 meters below the summit. The impact caused the aircraft to catch fire and crash at the foot of the mountain, resulting in one fatality.
The investigation
The BEA examined the wreckage, the pilot's flight history, and the aircraft's maintenance records. The investigation included a microscopic analysis of the flight control cables and a review of video footage captured by a bystander.
Investigators found that the rudder control cables were damaged. Specifically, the left rudder cable had a broken strand that had wound around the cable, a condition that likely occurred prior to the impact. The examination of the right rudder cable also revealed multiple broken wires near the pulleys. Regarding maintenance, the investigation revealed that the aircraft's chief pilot had been performing maintenance without following the manufacturer's specific manual. While the pilot performed visual and "rag tests" on the cables, he did not perform the 100-hour or 25-hour inspections as prescribed by the manufacturer, nor did he replace cables based on flight hours.
Findings
- The rupture of a strand on a rudder cable likely restricted rudder control by interfering with the cable's passage through a pulley, which compromised the aircraft's maneuverability.
- The pilot's failure to perform the required 25-hour and 100-hour inspections meant the extent of the cable damage remained undetected.
- The investigation could not determine why the pilot did not execute a nose-up maneuver to clear the terrain or deploy the airframe parachute after reporting control issues.