The improper installation of a hydraulic line at the right main landing gear (MLG) unlock actuator, which resulted in a total loss of system hydraulic pressure and failure of the landing gear to extend. Contributing to the accident was the failure of the right MLG shuttle valve due to corrosion, which prevented the right MLG from extending during the emergency blowdown activation.

Inadequate air traffic control actions that failed to establish and maintain required separation between the two airplanes. Contributing to the incident was inexperience on the part of the local controller, inadequate oversight by the tower controller-in-charge, and deficient facility procedures and training.

The pilot's failure to abort the landing while landing on a snow/ice-covered runway.