This is preliminary information, subject to change, and may contain errors. On February 7, 2015, between 1300-1400 UTC, a Robinson R66 helicopter, HB-ZOK, (s/n 0553) experienced a loss of engine power during recovery from an autorotation on a training flight. The pilot landed the helicopter, restarted the engine and returned to Bern Airport, Bern, Switzerland without further incident. This investigation is under the jurisdiction and control of the Swiss Transportation Safety Board. Under the provisions of Annex 13 of the Convention on International Civil Aviation as a State of Design, the United States has designated an accredited representative to participate in the investigation. Any further information may be obtained from: STSB Aviation Division Aerópôle 1 1530 Payerne Telephone: +41 58 466 33 00 Facsimile: +41 58 466 33 01 E-mail: info-av@sust.admin.ch Investigator-in-Charge Mr. Olivier de Sybourg Telephone: +41 58 466 33 07 E-mail: olivier.desybourg@sust.admin.ch This report is for informational purposes only and contains only information released by, or obtained from, the Swiss Transportation Safety Board.