CIVIL AVIATION REGULATIONS 1988 - REG 5.106
What kind of aeroplane may a commercial (aeroplane) pilot fly?
(1) Subject to subregulation (2), a commercial pilot (aeroplane) licence does not authorise the holder of the licence to fly an aeroplane as pilot in command, or co-pilot, unless the holder also holds:
(a) a
type endorsement or
class endorsement; and
(b) if the aeroplane has a
special design feature -- a
special design feature endorsement;
There's why you can fly a PA31 etc as Co-Pilot without there being a seperate co-pilot rating in the CAOs, MIHC.
Lynchpin has it correct. "Multi-Pilot Aeroplane" is whether or not the plane requires 1, or more than 1 pilot, according to the certification in the flight manual.
If the aircraft says you need one pilot, then that's how the rule is applied. Further bits like client requirements, u/s a/p etc does not then change the flight manual certification to multi-pilot! You are still flying a single-pilot aeroplane because nothing has changed, just flying it with multiple pilots.
If needing an ATPL was the case, how come so many things like Metros and B1900s can get around with CPL drivers on pax chtr for all these years?
Think of this extreme.
How would the Chief Pilot of a VFR piston company (who is NOT required to hold an ATPL) ICUS any of their pilots on a charter run if all of a sudden the C210 became a "multi pilot aeroplane" with the two of them onboard??????