Be careful, be very careful...
There are two issues here:
1. The privileges of a Comm-rated pilot, which I believe have been established, or have they:
Priveleges of a Comm pilot can be found in ANR 1976 (still valid without Part 61), 2.26. Par (b) states:
"to act as pilot-in-command in any aircraft operations other than the transport of passengers, cargo or mail for remeneration or hire ;"
I can hear all the Comm B1900 PIC shout, "Yes, but par (c) states I am able "to act as pilot-in-command in commercial air transport in any aircraft certificated for single-pilot operations;".
Guys, any laywer will tell you to look at the "intent of the law". When ANR76 was written, the B1900 has not yet flown and the intention was for Comm rated pilots to be able to fly as PIC on a/c weighing less than 12500lbs or fitted with 9 seats or less.
The fact that the law is taking so long to be updated has created a loophole used by the operators, but when an accident happens some day, some where in a country far far away, the laywers are going to have a field day.....
Lastly just a comment on Sandirons comment: "However, the FAA's requirements have no impact, implication or applicability to South Africa (not yet, anyway!!)"
Nothing can be further from the truth. In the case of the B1900, which has been certified by the FAA, the SACAA accepts that certification as is, and by implication also the AFM (which forms part of the certification process).
So unless somebody goes through a complete certification process with the SACAA for the B1900, and this includes developing a new AFM, the FAA AFM forms the basis of all limitations pertaining to way the a/c is operated - including the limitations placed for single-pilot ops by the FAA in the AFM.
And remember, you can only change the limitations to be MORE restrictive, not less restrictive.
Does this clear up the issue? In my opinion, there are some laywers sitting and waiting....