Lot of talk about minimums and weather, but to me the key to this sad event is how did the a/c end up inverted. Low visibility CFIT accidents are typically wings level, slight nose down impacts. Hard landing induced inversion happens if one wing separates (the MD 11 patern), does not appear to be case here. One possible scenario a mis-handled engine failure on applying go-around power, the resulting torque imbalance inverting the a/c very rapidly... ?