You still don't need an SIC rating for domestic US ops (but do once the flight leaves US borders), however it's not just a case of CPL & get in. The SIC still has to be trained on the aircraft type, including Pt 91 flights.
Once public transport is involved ie Pt 135 et al, then, as Towerdog wrote, the whole induction training system gets invoked along with a qualifying check ride.
Last edited by Tinstaafl; 10th Sep 2012 at 06:02.