The regional airline flight in Alaska that crashed, killing all 10 people onboard, was overweight before it took off, according to a preliminary report released Wednesday by the National Transportation Safety Board.

The preliminary report says the small plane was too heavy for conditions that cause icing at the speed and altitude it was flying.

It isn’t yet clear what specific role the weight might have played in the Bering Air Cessna Caravan’s crash, and whether other factors were involved.