[5] On Saturday, October 1, 1966, a Douglas DC-9 registered in the United States as N9101 operated as Flight 941 southbound from Seattle, Washington, to San Francisco, California, with intermediate stops in Oregon at Portland and Eugene.

[2] Under Air Traffic Control radar vector at 20:04:25 PDT, Flight 956 received descent instructions from Seattle Center.

After shearing numerous large fir trees, it struck the 30-35 degree upslope and slid uphill approximately 150 feet (45 m).

All of the extremities of the aircraft were accounted for, its landing gear was retracted, and no evidence of in-flight structural failure, fire, or explosion was found.

[5][9] The aircraft involved with registration N9101, a Douglas DC-9-14, serial number 45794, was delivered to West Coast Airlines just fifteen days prior to the accident.

The plane had entered service on Monday, September 26,[10] had flown a total of 164 hours, and had been maintained as required by the Federal Aviation Administration (FAA).

However, in the process of the investigation, the NTSB made these findings: In 1997, an anonymous donor placed a bronze plaque on a fir tree overlooking the crash site.

The inscription on the plaque reads: "IN MEMORY to the eighteen victims of West Coast Airlines Flight 956 that crashed here October 1, 1966."