What happened
On January 25, 2019, at approximately 14:25 local time, an AS3-B3 helicopter, registration I-EDIC, and a Jodel D.140E airplane, registration F-PMGV, collided in flight over the Rutor Glacier in La Thuile, Italy. The collision occurred at an altitude of approximately 2,777 meters AMSL in a mountainous region.
Following the impact, both aircraft sustained severe damage that rendered them unable to continue flight, leading to a crash of both airframes. The accident resulted in six fatalities: the pilot and four passengers from the helicopter, and two of the three occupants of the airplane.
The investigation
The ANSV investigation examined the flight paths, meteorological conditions, and the technical state of both aircraft. The investigation analyzed the flight trajectories to determine if the crews could have visually acquired one another. The inquiry also looked into the operational practices of the aircraft operators, specifically regarding flight limitations and border crossings in the Aosta Valley region.
Investigators reviewed radio communications and the physical wreckage to reconstruct the sequence of events. The investigation also considered the lack of collision avoidance technology on both aircraft and the visibility challenges posed by the mountainous terrain and shadows.
Findings
- The primary cause of the accident was the failure of the respective crews to visually acquire each other prior to the collision.
- The relative positions and trajectories of the two aircraft created significant blind spots; for the helicopter, the airplane was positioned in a higher, rear sector, while for the airplane, the helicopter was obscured by the aircraft's right wing and the shadows of the terrain.
- Both aircraft were operating in Class G airspace without onboard collision avoidance systems or proximity detection technology.
- The investigation noted a pattern of non-compliance with local flight limitations by some foreign operators in the region, specifically regarding landing practices in Italian territory without proper flight plan filings.
Safety action
- The ANSV recommended that EASA evaluate the mandatory installation of collision avoidance or proximity detection systems for aircraft operating under VFR in Class G airspace.
- The ANSV recommended that the French DGAC increase surveillance and safety promotion for operators to ensure awareness of Italian flight limitations.
- The ANSV recommended improved coordination between local police and ENAC to monitor and deter unauthorized flight activities in the Aosta Valley.