Complex sentence: On 11 May 2015, P01 conducted its first flight from Buochs Airport, Switzerland, this maiden flight for the type lasted for a total of 55 minutes; the occasion marked the start of test flights for the aircraft's two-year certification campaign.
Split into simpler sentences: On 11 May 2015, P01 conducted its first flight from Buochs Airport, Switzerland, for a total of 55 minutes. The occasion marked the start of test flights for the aircraft's two-year certification campaign.