What happened
On the morning of February 8, 2024, an Airbus EC1s5B1 helicopter, registered F-HEGT, was conducting a commercial passenger flight from Chambéry toward Courchevel. The crew, consisting of two pilots, was cruising at 4,000 ft and had transitioned to the regional mountain radio frequency. Simultaneously, a vintage Nord N1203 aeroplane, registered F-AYVV, departed Albertville for a post-maintenance check flight. The aeroplane was also cruising at 4,000 ft, following a similar flight path.
At approximately 11:45, the two aircraft were on a head-on collision course with a combined closing speed of roughly 280 kt. The helicopter pilot spotted the aeroplane only one to two seconds before impact and initiated an emergency right turn and descent. While this maneuver prevented a direct head-on impact, the tips of the helicopter's main rotor blades struck the left wing of the aeroplane.
The helicopter pilot performed an emergency landing in a nearby field, while the aeroplane pilot, despite damage to the wing and fuel tank, managed to return to Albertville aerodrome for a safe landing. There were no fatalities among the eight people on board the helicopter or the two crew members on the aeroplane.
The investigation
The BEA examined the flight data from the helicopter's onboard recorder and analyzed the flight paths of both aircraft. The investigation focused on the visibility conditions, the use of radio frequencies, and the equipment installed on both aircraft. Investigators noted that the collision occurred in class G uncontrolled airspace, where the primary method of separation is the "see and avoid" principle.
Findings
- The aircraft were flying on a head-on path with a very high relative closing speed.
- The Nord N1203 was not equipped with a transponder at the time of the accident, as the unit was scheduled for installation following the check flight.
- The helicopter's TCAS did not provide a warning prior to the collision.
- The high relative speed and head-on approach significantly limited the pilots' ability to detect the conflict using visual scanning.
- The aeroplane's white paint and the presence of cloud cover may have reduced the contrast necessary for early visual acquisition.