Experimental aircraft crashes during emergency landing in Swiss Alps

Casualties unknown • Oberwald, VS, CH

An experimental Opus 3 aircraft struck a mountain slope near the Furka Pass, resulting in serious injuries to the pilot after an attempt to navigate the terrain failed.

What happened

On August 23, 2005, an experimental Opus 3, registration OY-CYZ, was conducting a flight from Rarogne, Switzerland, to Denmark. While navigating the Alpine region, the pilot encountered strong downdrafts near the Grimsel Pass. As the aircraft approached the Furka Pass, the pilot realized the aircraft's altitude was insufficient to clear the 2,431-meter peak.

GPS data revealed that while the aircraft had initially climbed to nearly 5,800 feet, the pilot began a series of climbs and descents to stay beneath the cloud base. This maneuver resulted in a significant altitude deficit at the foot of the pass. With an airspeed of only approximately 60 knots, the pilot determined that a 18/0-degree turn was not possible. To avoid a loss of control, the pilot executed an emergency landing on the upward slope ahead. The aircraft struck the ground violently, bounced, and came to a rest, leaving the single pilot with serious injuries.

The investigation

The investigation, conducted by the AAIB, examined the wreckage and GPS flight data. Investigators found no evidence of mechanical failure, engine malfunction, or medical issues involving the pilot. The aircraft's mass and center of gravity were within limits, and sufficient fuel was on board for the intended mission. The investigation also noted that the aircraft was not equipped with an emergency location beacon (ELBA), though the pilot was able to use a mobile phone to alert rescuers.

Findings

  • The primary cause of the accident was an inappropriate flying tactic in a mountainous environment.
  • The pilot's decision to fly a profile of successive climbs and descents to avoid clouds led to an insufficient altitude for crossing the pass.
  • The low airspeed prevented the pilot from safely performing a turn to return to the valley.
  • The pilot's choice to land on the upward slope at full power and a nose-up attitude prevented a more catastrophic impact and contributed to his survival.

Probable cause

The accident was caused by an unsuitable flight technique in the Alps, specifically a flight profile that resulted in insufficient altitude and airspeed to clear the terrain or execute a safe turn.

Frequently asked questions

What happened in the 2005-08-23 EXPERIMENTAL Opus-3 accident near Oberwald, VS, CH?

An experimental Opus 3 aircraft struck a mountain slope near the Furka Pass, resulting in serious injuries to the pilot after an attempt to navigate the terrain failed.

What aircraft was involved and where did it happen?

The accident on 2005-08-23 involved a EXPERIMENTAL Opus-3, registration OY-CYZ, at Oberwald, VS, CH.

What was the probable cause of the accident?

The accident was caused by an unsuitable flight technique in the Alps, specifically a flight profile that resulted in insufficient altitude and airspeed to clear the terrain or execute a safe turn.

Investigation report by the Swiss Transportation Safety Investigation Board (STSB / SUST). Original record: https://www.sust.admin.ch/inhalte/AV-berichte/2009_e.pdf. This page is a structured re-presentation; facts and quotes are in the Swiss Transportation Safety Investigation Board (STSB), Switzerland.

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