Replaced the burnt out chip on the AR Drone motor pcb today and put it all back together and connected battery and hit take off and motor spun up and then motors cut out.
Tried again and same thing.
Lucky enough I did buy 4 of them anyways.
So pulled it all apart and this time replaced the other 2 MOSFETS and tried again and his time all works fine 🙂
So looks although only 1 chip blew apart it does indeed kill all 3 and for future if/when this happens again, will have to replace all 3 at a time and not just the one thats blown apart.