What happened
On 12 January 2021, a Schweizer 269C-1 helicopter, registration F-HAGO, was conducting a local VFR flight in the mountainous Val d'Ese area of Corsica. The pilot, accompanied by a passenger, was flying toward the Bocca della Calle pass. While crossing the pass with a tailwind, the pilot experienced a decrease in main rotor speed and a subsequent loss of altitude.
Unable to maintain altitude due to insufficient power reserves, the pilot was forced to perform a landing on a snow-covered slope behind the pass. Upon contact with the soft, snow-covered ground, the helicopter's skids sank, causing the aircraft to tip forward and the main rotor to strike the snow. The aircraft was destroyed in the impact.
Following the crash, the occupants left the wreckage to seek mobile phone coverage, walking approximately two hours toward the Val d'Ese ski resort. They eventually reached a ridge where they were able to contact air traffic control in Ajaccio. They were subsequently rescued by a PGHM helicopter.
The investigation
The BEA examined the wreckage, which was located at an altitude of 1,937 m. Investigators noted that the tail boom was broken and the tail rotor had been torn off. While the flight control linkages remained continuous, no technical mechanical failure was found to explain the decrease in rotor speed. Meteorological analysis indicated the presence of horizontal and vertical wind shear at the pass.
The investigation also reviewed the survival aspects of the incident. The aircraft's fixed Emergency Locator Transmitter (ELT) activated automatically during the landing, but because it lacked a GNSS receiver and was not registered on the RFBD, authorities faced difficulties pinpointing the exact location. Furthermore, the occupants did not activate or carry their portable Personal Locator Beacon (PLB) when leaving the site, which prevented the transmission of their precise GPS coordinates.
Findings
- The primary cause of the altitude loss was a decrease in main rotor speed likely triggered by aerological conditions while crossing the pass.
- The pilot's inability to counter the descent was exacerbated by the lack of power reserve and the presence of downdrafts.
- The helicopter tipped forward during landing because the skids were not equipped with skis for snow operations.
- The lack of specific mountain flying training contributed to the difficulty in managing the aircraft during the encounter with turbulence and downdrafts.
- The delay in locating the occupants was influenced by the unregistered status of the ELT and the decision by the occupants to leave the wreckage without their portable PLB.