Lynchpin seems to provide the best explanation so far, but if Metros and B-1900s are only single pilot certifiied for all ops, then why are there co-pilot endorsements for these types?
From another point of view, there are co-pilot endos for Kingairs and Twotters too. What are the categories of operation where 2 pilots are required?
Is the existance of this endorsement purely to satisfy the autopilot scenario?
I'm not inflexible. This would seem to support the case for co-pilot time if it is the sole purpose.
I vaguely recall that there is a passenger limitation on single pilot operations. I think above a certain number of pax you need two crew + GPWS/TAWS B. 9 and 14 are two numbers that mean something but I can't remember which one is what.
That's why these aircraft have two crew qualifications. So you can fly the aircraft to the certified limits. I don't believe you can fly a DHC-6/B1900D/M23 etc Single pilot with 16/19 pax on board. The single pilot bit is for ferry and/or freight only operations. For the guys flying M23 with a CPL and pax I'll bet there is a passenger limit. He wouldn't be blasting off with 19 pax.
End of the day if you are legally
required for whatever reason to be in the RHS and you are endorsed and have a IR (if required for the operation) it is copilot time. Otherwise it could be argued that you are forging flight time by not logging it.