From what I'm hearing on the radio, the crash happened very shortly after takeoff. That's always the most dangerous part of any flight. While crews train all the time to handle that kind of emergency, the plane was heavily loaded making the situation much more difficult to handle. If an catastrophic engine failure happened on takeoff, it might've damaged the hydraulics or caused a chain of events that would've made the plane unflyable (as in the Concorde crash last year).

The plane probably went down at a relatively low speed. It's possible the crew got off a Mayday. Recovering the cockpit voice recorder and flight data recorder shouldn't be too difficult.