Passengers - Reference: Reg. (EU) No 965/2012 on Air Operations: Article 5(7)
Except for crew members, persons other than those indispensable to the mission shall not be carried on board of flights, which take place immediately before, during or immediately after specialized operations and are directly connected to those operations.
When SPO related rules apply to a flight or a number of flights, passengers (fare paying or not) cannot be carried on board such flights. In some SPO operations, the concept of “passenger” and “task specialist” do blend into each other. Therefore, for regulatory and risk mitigation purposes persons carried on board are considered task specialists, even if their “task” is to enjoy 0-G flight, a tandem jump, or a looping. The rules call for task specialists to be instructed on their tasks, including the risks connected to those tasks of which they are not sufficiently or at all informed.
If passengers are being transported, the flight has to be performed in accordance with Part-CAT or Part-NCC or Part-NCO, as applicable.