Investigation Summary
The accident occurred during a period of dense fog at San Francisco International Airport. Captain Kohei Asoh elected to perform an automatic-coupled Instrument Landing System (ILS) approach, a procedure he had not previously executed in the DC-8-62. Due to a lack of familiarity with the Sperry Flight Director System, the crew did not properly couple the localizer and glide slope. The aircraft began a constant, uninterrupted descent from 2,000 feet that continued until it struck the water. Despite several cockpit instruments indicating they were below the glide slope, the crew did not recognize the error until the landing gear and right wing struck the water at approximately 137 knots. The aircraft came to rest in only 7 feet of water, allowing for a successful evacuation. The salvage operation was a significant engineering feat, involving four crane barges to lift the 130-ton aircraft from the bay floor. After being rinsed with 20,000 gallons of fresh water to prevent salt corrosion, the aircraft was repaired by United Airlines for $4 million and flew for another 15 years.
Final Conclusions
The NTSB determined the probable cause was the improper application of prescribed procedures for an automatic-coupled ILS approach, stemming from a lack of familiarization and infrequent operation of the installed flight director and autopilot system. Contributing factors included a lack of specific training on the Sperry Flight Director System and potential coordination issues between the Japanese captain and the American first officer.
Photographic Evidence (1)
Video Analysis
Crashing into San Francisco Bay | Japan Air Lines Flight 2 — A detailed look at the 1968 ditching of a JAL DC-8 in San Francisco Bay and the famous 'Asoh Defense' that followed.
If playback is blocked, the owner has disabled embedding — use the link above.
Airframe & Maintenance
Crew Experience
Captain
Captain Kohei Asoh, age 46
First Officer
First Officer Joseph Hazen, age 34
Systems & Failure Modes
Sperry Flight Director System
The integrated system used to provide visual cues for navigation and approach. The investigation found the crew was not adequately trained on its specific operation in the DC-8-62.
Automatic-Coupled ILS
A system designed to link the autopilot to the ILS radio beams. The captain failed to set the autopilot for ILS capture until the plane was already below the glide slope.
Interesting Facts
- 01The aircraft was only five months old at the time of the accident.
- 02The aircraft was named 'Shiga' at the time of the accident.
- 03Captain Asoh famously took full responsibility for the accident, an act of candor that became known as the Asoh Defense.
- 04The aircraft was salvaged from the bay 55 hours after the ditching.
- 05Repairs cost $4,000,000, which was roughly half the original purchase price of the aircraft.
- 06The aircraft was renamed 'Hidaka' after its return to service and flew for JAL until 1983.
Safety Actions & Advisories
Training Program Revision
Japan Airlines revised its flight crew training program to include mandatory training and familiarization with the Sperry Flight Director System.