Investigation Summary
Flight 956 was a multi-leg regional service. Earlier on the day of the accident, the aircraft and crew had operated the reverse route from Seattle to San Francisco as Flight 941. After an hour on the ground in San Francisco, they departed as Flight 956. The accident occurred on the short leg between Eugene and Portland, which was scheduled to last only about 20 minutes. At 20:04 PDT, while under radar vectors, the crew acknowledged a clearance to descend from 14,000 feet to 9,000 feet. Shortly after, the controller instructed a right turn to a heading of 300 degrees for the approach to Portland International Airport. Radar contact was lost during this turn. The flight data recorder later revealed that the aircraft did not level off at 9,000 feet but continued a steady descent to approximately 4,000 feet. The aircraft struck the eastern slope of a 4,090-foot ridge at an elevation of 3,830 feet while in a 30-degree right bank. A sharp climbing maneuver was initiated only two seconds before impact, suggesting the crew became aware of the terrain at the last moment. The cockpit voice recorder was recovered but was so severely damaged by the post-impact fire that no usable data could be retrieved, leaving the reason for the unauthorized descent a mystery.
Final Conclusions
The Civil Aeronautics Board (CAB) determined the probable cause was the descent of the aircraft below its clearance limit and below that of surrounding obstructing terrain, though the Board was unable to determine the cause of such descent. The investigation confirmed the aircraft was airworthy, the pilots were properly certified, and there was no evidence of mechanical failure in the engines or flight control systems.
Photographic Evidence (1)
Video Analysis
Deadly Descent | West Coast Airlines Flight 956 — A detailed look at the mysterious 1966 crash of a brand-new West Coast Airlines DC-9 into the Oregon wilderness.
If playback is blocked, the owner has disabled embedding — use the link above.
Airframe & Maintenance
Crew Experience
Captain
Charles C. Warren. Undergoing route qualification.
Check Captain
Donald Alldredge.
First Officer
Pete M. Labuski. Occupying the jump seat.
Systems & Failure Modes
Autopilot
The autopilot was found to be engaged at the time of impact; investigators examined if a malfunction caused the continued descent, but no evidence of failure was found.
Cockpit Voice Recorder (CVR)
The CVR was recovered from the wreckage but was rendered unusable due to severe heat damage from the post-crash fire.
Flight Data Recorder (FDR)
The FDR provided a usable record, confirming the aircraft descended steadily past its assigned altitude of 9,000 feet to 4,000 feet.
Interesting Facts
- 01The aircraft had been delivered to West Coast Airlines 15 days prior to the accident and had entered service only five days earlier.
- 02This was the first fatal accident involving a Douglas DC-9 aircraft.
- 03The aircraft was being flown on autopilot during the descent.
- 04The impact occurred at a speed of approximately 300-350 knots.
- 05The flight data recorder showed an abrupt climb was initiated two seconds before impact.
- 06In 1997, an anonymous donor placed a bronze memorial plaque on a tree overlooking the crash site.
Safety Actions & Advisories
CVR Fire Protection Standards
The total loss of data from the cockpit voice recorder due to post-impact fire led to increased scrutiny of the fire-resistance standards for flight recorders, as the unit in this crash failed to protect the tape despite being located in the tail section.