Don't fly ATR myself...
Sounds very like the shorts crash out of Edinburgh.
The crew turned on the engine heaters and opened the separator doors both together. Which caused a huge lumps of ice to go through both engines, both at the same time causing flame out together.
Don't know what the penalty is for icing on departure on the ATR but hey could have gone for icing off then turned it on as the gear came up.
Seems there is a rather large group of pilots that think this is acceptable not realising that the icing performance is required if your going to be in it before the end of the third phase.
If there is ice formed in the bottom of the intake and forms a lump and you put the heaters on, that just melts what is attaching it to the bottom and the whole lot lifts up and blocks the compressor.
I was always taught with engine controls to operate anti-ice or de-ice individually and wait to see what the effect was and then do the other engine.
We shall see what the investigation turns out