Helicopter crash in French Alps following weather degradation

Casualties unknown • Conséquences et dommages, FR

An Eurocopter AS 350 B2 crashed into a rocky ravine near Piène Haute, resulting in three fatalities during an aerial survey mission.

What happened

On December 7, 2010, at approximately 14:54, an Eurocopter AS 350 B2, registration 3A-MTP, departed Nice airport for the Roya Valley. The flight, operated by Héli Air Monaco, was an aerial survey mission intended to assess damage from a recent landslide. The crew included the pilot and two passengers.

After departing Nice frequency at 15:00, the aircraft disappeared from radar at 15:07, likely due to terrain masking. Witnesses in Piène-Haute reported hearing the helicopter circling above them around 15:20, appearing to search for a landing site. At that time, thick fog had reduced visibility to approximately fifteen meters. Witnesses observed the aircraft descending along a ridgeline where the slope increased sharply near the summit. Shortly after, a blade strike sound and a heavy thud were heard.

The investigation

The investigation established that the aircraft struck a rocky ravine flank at an altitude of 550 meters, roughly twenty meters below the nearest ridgeline. Evidence at the impact site, including traces of fire and explosion, indicated the helicopter was in an ascending flight path. Marks on a nearby tree suggested the aircraft was in a pitch-up attitude at the moment of impact. The wreckage showed high-energy impact forces, and the rotor was found to have been driven by the engine at the time of the crash.

Regarding the pilot, the investigation noted he held a valid CPL(H) and instructor rating, with 4,670 total flight hours. However, he did not hold an instrument rating. As the person responsible for pilot training within the company, he had personally decided to undertake this mission.

Findings

  • The primary cause was the pilot's decision to attempt a landing or begin a reconnaissance mission despite deteriorating meteorological conditions.
  • While flying at low altitude along the ridgeline, the aircraft entered a cloud layer. It is believed the pilot lost external visual references where the ridge slope changed abruptly.
  • The aircraft entered a collision with the terrain while attempting to regain altitude to exit the cloud layer.
  • The pilot's lack of instrument flight training likely contributed to the loss of control within the clouds.

Probable cause

The accident was caused by the pilot's decision to conduct a survey mission in weather conditions that did not permit safe flight, leading to a loss of visual references and a subsequent collision with terrain while attempting to climb out of a cloud layer.

Frequently asked questions

What happened in the 2010-12-07 Eurocopter AS 350 B2 accident near Conséquences et dommages, FR?

An Eurocopter AS 350 B2 crashed into a rocky ravine near Piène Haute, resulting in three fatalities during an aerial survey mission.

What aircraft was involved and where did it happen?

The accident on 2010-12-07 involved a Eurocopter AS 350 B2, registration 3A-MTP, at Conséquences et dommages, FR.

What was the probable cause of the accident?

The accident was caused by the pilot's decision to conduct a survey mission in weather conditions that did not permit safe flight, leading to a loss of visual references and a subsequent collision with terrain while attempting to climb out of a cloud layer.

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