According to a first hand witness (offshore helicopter pilot who heard the call and who was the first on scene, giving the location to ATC) the mayday call said "double engine failure."
If that is the case then I imagine at their altitude they were all passengers. I read another eye-witness state that the approach shortly before hitting the building suggests a nose up, tail down stance of the aircraft, which indicates the crew were at least in control, or attempting to control the aircrafts descent and landing.
I'm no pilot but in that situation I can only imagine it's a case of "Keep her up as long as I can, try to find a clearing". Is the entire area as densely populated as it looks or could it be they were aiming for a clearing but sadly fell short?
A shame nevertheless and hopefully an in-depth investigation ensues. Whenever I see crash scenes filled with on-lookers it always makes me squirm as in those situations evidence can be disturbed, parts and equipment go missing etc - I suppose in a continent such as Africa it's impossible to police such a situation.