On August 4, 2017, at 0720 UTC, a Piper PA-28-181, Swiss registration HB-PER, owned and operated by a private individual, impacted mountainous terrain near Berghaus Diavolezza, Switzerland. The pilot and two passengers on board were fatally injured. A third passenger received serious injuries. The airplane sustained substantial damage. Visual meteorological conditions prevailed at the time of the accident. The foreign, non-scheduled local flight departed Samedan, Switzerland, about 0710 UTC.This investigation is under the jurisdiction of the government of Switzerland. Any further information regarding the investigation can be obtained from the Swiss Transportation Safety Investigation Board at: Swiss Transportation Safety Investigation Board Aviation Division Aeropole 1, Route de Morens, 1530 Payerne Switzerland Telephone: +41 26 662 33 33 Facsimile: +41 26 662 33 01 E-mail: info@sust.admin.ch This report is for informational purposes only and contains only information released by, or obtained from, the STSB of Switzerland.