Interesting. Lots of "lawyer speak" in there but you'll get the idea:
“This program allows a pilot employed by the part 135 air carrier/operator and serving as an assigned second in command (SIC) in a multiengine airplane or single-engine, turbine-powered airplane to log SIC flight time during operations that do not require a second pilot.”
https://www.faa.gov/documentLibrary/.../AC_135-43.pdf