What happened
On the morning of the accident, Western Air Lines flight 4CO departed Denver at 07:03, operating under an IFR flight plan. The Convair 580 climbed to a cruising altitude of FL220 before descending toward Casper. At approximately 07:36, the crew contacted Casper approach control, reporting their position near the Evansville Intersection. The controller provided options for a localizer back course approach for runway 25, a circle to runway 3, or a straight-in landing.
Weather conditions at the time included light snow and low visibility, with winds from 040° at 9 knots. The crew was notified that runway 7/25 had been plowed but contained approximately 1/4-inch of powder snow, and braking action for a previously landed Convair 580 had been reported as poor. During the approach, the tower controller informed the crew of a disabled snow blower located near the intersection of runway 21 and the left side of runway 25.
As the aircraft approached the field, the first officer provided altitude callouts, noting the aircraft was approaching minimum descent altitude (MDA). At 07:42:25, the first officer reported the runway in sight. The captain then initiated the final descent with flaps set at 30°. The aircraft crossed the threshold at a speed of reference speed plus 15 knots. Upon touchdown, the plane traveled 2,375 feet from the departure end of the runway before veering right of the centerline. After hitting several metal stanchions located 200 feet off the runway end, the aircraft entered a shallow irrigation ditch 280 feet beyond the runway. The aircraft finally came to a stop approximately 800 feet past the departure end of the runway.
Findings
The accident was caused by the pilot-in-command's failure to execute a missed approach despite the risks of the non-precision approach. Contributing factors included the pilot's failure to properly assess the aircraft's position relative to the threshold, as well as excessive speed and height during the threshold crossing. Additionally, the crew failed to provide necessary altitude or position callouts during the descent.