The flight crew’s inability to maintain the airplane on the runway centerline after touchdown due to the reduced braking action resulting from the deteriorating weather conditions, which caused the airplane’s departure from the runway surface. Contributing to the accident were the delay in performing the runway assessment for undetermined reasons and failure to close the runway. Also contributing to the accident was the controller’s failure to advise the accident flight crew that braking action was no longer consistent with the previously published notice to air mission, which described braking action as good across all three runway zones.

The presence of deice fluid on the floor, which resulted in a slip hazard and an injury to the flight attendant.