I don't know what Mandala is like nowadays but the fact that it has had '7 hull losses' since the airline started operations is meaningless. The airline's last 'hull loss' (also fatal) was in July 1992 - 13 years ago - with a Viscount. Todays tragic accident was the first 'hull loss' or fatal accident suffered by the airline with jets.
Just 'bean counting' the number of accidents an airline has had without detailed analysis of the full circumstances and probable causes is not much use and, even then, looking at accidents that happened years ago does not necessaryly tell you anything about the operator today.