J41 vs Brasilia....
keitaidenwa has hit the first nail on the head - Garrett engines require more attention than pratts by both pilots and engineers meaning that operating them away from "Home" or where you fly many sectors away from maintenance facilities can be risky.
They also don't apreciate dust or heat either making more usefull in Europe or the US than in most African operations.
Spare parts are another bone of contention in such that as the J41 was produced in such low numbers compared with the Brasilia that most of the commonly used parts are difficult or expensive to obtain, and in the past unless you were SA Express only available from the US or EU.