Eyewitness reports sugesting some sort of explosion are quite common. Not to blame the eyewitness, but such stuff happens in a few seconds and it is difficult to locate the "bang". A full loss of engine power is possible explanation, if both engines are lost in final approach there is basically no exit strategy and a crash is inevitable. But let's wait a few days, the NTSB works rather quick lately.Sorry my German is not good enough to write my comment here in German. But I hope you all speak enough English to understand.
I live in Miami and hear news updates about the crash on the local radio or read it on my home page regularly.
Earlier this morning they said on the radio there were eyewitnesses who saw an explosion before it went down and the engines "making strange noises".
As an aviation author with experience this almost looks to me as what I initially thought brought down this aircraft, a birdstrike in one of the engines.
I have no further information other than what I hear on the radio here while the investigation is ongoing.
But that is my guess and the results of the investigation by the FAA will clear it all up in a few weeks.
I have no idea how the approach was and what the weather was like at time of the landing attempt.
I hope this sheds some light on this unfortunate event but when the FAA results are in we will know the cause of this fatal crash.