On January 28, 2019, about 0617 mountain standard time, Frontier Airlines flight 450, an Airbus A320-214, N220FR, was struck by the tug during pushback operations at Denver International Airport (KDEN), Denver, Colorado. There were no injuries and the airplane received substantial damage. The regularly scheduled domestic passenger flight was operating under the provisions of Title 14 Code of Federal Regulations Part 121 from KDEN to Buffalo International Airport (KBUF), Buffalo, New York. According to flight crew statements, the crew advised the tug driver they were cleared to push back, either tail east or straight back. At the time of the accident, dark night conditions existed and the ramp was contaminated with snow. During the pushback, the flight crew started No. 1 and 2 engines. The tug driver pushed the airplane back with its empennage towards the east and then notified the captain that he would pull forward to straighten them out. As the tug driver pulled the airplane forward and was coming to a stop the airplane's nose began to drift to the left. The tug detached from the airplane and impacted the right forward fuselage and right engine air intake resulting in substantial damage. The captain noted that the nose swung to the left, and then said it felt as if the airplane was moving backwards. According to the operator, on the morning of the accident, the ramp management company had instructed their ground personnel that all pushbacks should be straight back pushes due to the snowy conditions. It is likely that the angle of the towbar from pushing the airplane back to the east, combined with the snow contaminated ramp and the engine idle thrust, caused the tug driver to lose control of the tug during the pushback.