i might be incorrect, but i had thought that 350's generally did not burn up like this
I watched one burn after a take off mishap.
Tank is made of thick plastic, is it polycarbonate or something similar that is exotic and strong?
From my study of 147 aerial filming accidents my feeling is that the as350 frame does not do as well as other frames in protecting the occupants from crush injuries or ejection.
So fire is less an issue as occupants are probably already deceased.
I say probably as not all coroners reports are to hand.
If anyone wants the accident list for further research send me a PM
Mickjoebill