14 C.F.R. § 135.99 Composition of flight crew.
Title 14 - Aeronautics and Space
(a) No certificate holder may operate an aircraft with less than the minimum flight crew specified in the aircraft operating limitations or the Aircraft Flight Manual for that aircraft and required by this part for the kind of operation being conducted. (b) No certificate holder may operate an aircraft without a second in command if that aircraft has a passenger seating configuration, excluding any pilot seat, of ten seats or more.
Title 14: Aeronautics and Space
PART 135—OPERATING REQUIREMENTS: COMMUTER AND ON DEMAND OPERATIONS AND RULES GOVERNING PERSONS ON BOARD SUCH AIRCRAFT
Subpart B—Flight Operations
§ 135.99 Composition of flight crew.
