Shortly after the crash there was a lot of speculation about the pitot system due to the auto reports sent on the aircraft’s maintenance info channel.
IIRC, the pitot/static system has had heated fixtures, just not high enough wattage for a worst case situation of severe rime ice.
Several other Airbus flights suffered loss of airspeed indication and shutdown of the auto flight functions. Those flights were able to fly through the problems using a specified pitch and engine power setting for just such an occurrence.
From the info released, the aircraft looks to have entered a deep stall, complete with 10 or more degrees of side to side wing rocking (normal for deep stall flight).
I haven’t seen any mention as to how deep a stall this aircraft can recover from.
Not rime ice, I ment to say impact icing due to super cooled water at altitude.