Cemair:
Perhaps you could end some of the speculation by providing some facts.
You have already confirmed what many here have observed: That the crew were well experienced and familiar with the area, competent, and highly skilled. That leads to the reasonable presumption that crew error was likely not the primary cause of this accident.
What about the aircraft? Was it equipped with functional Class A TAWS? Considering that GNSS is the only navigation system that reliably serves the area your aircraft operated in, was the aircraft equipped with dual GPS, both installed in accordance with TSO and both approved by the SA CAA as the primary means of enroute and approach navigation? Do your operations specifications include SA CAA approval for use of RNP approaches? Did you provide the crews with the training the SA CAA requires to use RNP approaches?
Were the engines overhauled by the same organization that overhauled the engines on your B-1900 that crashed in Southern Sudan May 2, 2008?
We appeal to you for facts.