Theo Staub, president and COO of Jet Aviation North America, and Colin Bond, CFO of the Jet Aviation group, “have decided to leave the company,” according to a statement from the Swiss-based business aviation group. Hartwig Grevener, formerly a CFO with an airline catering firm, is joining Jet Aviation as new group CFO, while a new president and COO for the company’s North America operation “will be appointed later in the year.”

No immediate reasons were disclosed for the sudden departures. “I cannot add anything to what we announced in the press release,” said a spokesman.

Kurt Sutterer and Gary Dempsey will lead Jet Aviation’s North American business on an interim basis. Sutterer is president of Jet Aviation’s newly acquired Midcoast Aviation and a member of the extended group management, while Dempsey is Jet Aviation’s senior v-p of maintenance and OEM development for North America.