sad news for the crew and the family of the people who passed away.
I am not from india, but the weather in delhi was pretty bad. We had effects of it out here too and had no flights that day.
Guessing it was the bad weather and most probably got slammed to the ground. and as it looks like it was not a case of CFIT though and regarding the CVR as much as I know about Pilatus they do have a FDR if not a CVR. Not sure if it was the NG model or not. If it was Pilatus does offer FDR and CVR so its a choice of the operator to get it or not.
Regulations do not require it though.
Anyway, would be interesting to know the conclusion about it.