Investigation Summary
The flight, operated by Marine Transport Squadron 152 (VMR-152), departed El Toro at 10:30 am. Upon reaching the San Francisco Bay Area, the pilot, Major Alexander Baker Watson, was instructed to enter a holding pattern due to heavy fog and drizzling rain. At 1:42 pm, after being stepped down to 3,500 feet, Watson reported he was on the beam of the Newark radio beacon and beginning his final approach. Three minutes later, the aircraft struck a steep canyon wall on Sunol Ridge. Local witnesses reported the plane was flying extremely low, barely clearing the west wall of Stonybrook Canyon before the impact. The crash resulted in an intense post-impact fire that scattered debris over 300 yards. A significant administrative error followed the crash when the Marine Corps realized the passenger manifests for two different flights had been switched, leading to the initial misidentification of the victims and causing families to receive incorrect death notifications.
Final Conclusions
The Marine Corps board of inquiry determined the cause of the accident was pilot error. The investigation found that the crew deviated from the prescribed flight path and the Newark radio beacon, and conducted the descent in an unprescribed manner under low-visibility conditions. The aircraft was approximately six miles off course at the time of impact.
Video Analysis
No video analysis linked for this case file yet.
Systems & Failure Modes
Newark Radio Beacon
A navigational aid used by the crew to align with the approach path to NAS Alameda; the investigation found the crew had deviated from this beacon.
Altimeter
Investigators considered whether the pilots had misread their altitude, as the plane lost significant altitude very quickly before impact.
Interesting Facts
- 01The crash was the first involving a Douglas R5D-2 Skymaster.
- 02One passenger, Donald J. Fraser, was a stowaway who boarded the flight at the last minute to surprise his parents.
- 03The aircraft struck the ridge at 1,330 feet, despite needing to be at least 1,600 feet to clear the local terrain safely.
- 04Initial rescue efforts were hampered by fog, causing helicopters to briefly mistake debris from a 1951 United Air Lines crash for the new wreckage.
- 05The aircraft, a Douglas R5D-2 (DC-4) with MSN 18331, was manufactured in 1944.
Safety Actions & Advisories
Manifest Verification Procedures
Following the significant error where manifests for two separate flights were switched, the Marine Corps reviewed administrative procedures for passenger logging to ensure that ground personnel and flight crews verified the specific personnel on board each individual airframe prior to departure.
Known Controversies & Unanswered Questions
Manifest Error
Reference ↗The Marine Corps accidentally switched the manifests of two transport flights, resulting in families of survivors being told their loved ones were dead, while families of the deceased were not immediately notified.