What happened
On January 17, 2013, a private pilot operating an Eurocopter AS3-B (registration F-GZFJ) was conducting a series of flights to monitor an automobile rally. Following the third flight of the day, the pilot performed a visual reconnaissance of a landing site in Saint-Julien-Molhesabate, France, and began an approach on a heading of 020°.
As the aircraft descended to an altitude of only a few meters, the downwash from the main rotor disturbed the fresh snow on the ground, creating a cloud of powder that obscured the pilot's external visual references. Unable to maintain orientation, the pilot continued the landing attempt, resulting in the helicopter striking the snowy ground in a nose-down attitude. The impact caused heavy damage to the aircraft.
The investigation
The investigation established that while the pilot had landed at this same location earlier that morning on a compact snow surface, recent snow showers had deposited several centimeters of powdery snow between the two landings. Meteorological conditions at the time of the accident included winds from 340° at 15 to 20 knots with gusts up to 28 knots, and visibility of approximately 1,000 meters.
The pilot, who had 1,028 total flight hours (including 700 on type), was experienced in mountain flying and landing on snowy surfaces. Investigators examined the landing techniques recommended for such conditions, which include maintaining sufficient forward speed to stay ahead of the snow cloud or utilizing ground references like trees or poles to assist with the flare.
Findings
- The primary cause of the accident was the use of inappropriate landing techniques for a powdery snow surface.
- The pilot's familiarity with the site from an earlier landing that day likely contributed to a reduced level of vigilance.