Matt, you give your location as DRC, so I assume in some proximity to the crash.
Without a full accident investigation, you are unlikely to learn the reasons for the accident.
Engine power loss could be a result of bad maintenance or fuel contamination, low fuel, or even bad switchology in the cockpit.
The initial loss of control was apparently not responded to by the PF and allowed to continue. How the aircraft arrived in its predicament is unknown, so we do not know how much time the crew had to react to their problems and prepare for an approach.
That the aircraft was not considered airworthy is still another issue, but is indicative of the willingness of the operators to bend regulations to suit themselves. This means that no manufacturers support was available, and no government oversight of operations. In essence, an accident waiting to happen.