Investigation Summary
Flight 301 was operating in a period when Japan was still under Allied occupation following World War II. The aircraft, a Martin 2-0-2, was leased from Northwest Airlines and operated by American pilots as part of the arrangement for Japan Air Lines' early operations. On the morning of the accident, the flight departed Haneda for Fukuoka with a planned stop at Itami. While flying in marginal weather conditions south of Tokyo, the aircraft deviated from its intended flight path. It struck the volcanic slopes of Mount Mihara on the island of Izu Oshima. Because the aircraft lacked flight recorders and the occupation authorities withheld critical ground-based communications tapes, investigators could not definitively explain why the crew descended or deviated into the terrain.
Final Conclusions
The Japanese government aircraft accident investigation committee concluded that the aircraft had deviated from its original course. While the exact reason for this deviation remained unknown due to a lack of evidence, the committee proposed that the accident was likely the result of a navigational error by the flight crew.
Photographic Evidence (1)
Video Analysis
Japan Air Lines Flight 301 Aftermath Footage | 9 April 1952 — Historical footage and overview of the Japan Air Lines Flight 301 accident involving the Martin 2-0-2 'Mokusei-go' on Mount Mihara.
If playback is blocked, the owner has disabled embedding — use the link above.
Systems & Failure Modes
Navigation Instruments
The investigation focused on a potential failure or misinterpretation of navigational aids that led to the course deviation.
Air Traffic Control Communications
The lack of access to ATC tape recordings from Haneda Airport prevented investigators from understanding the instructions given to or acknowledged by the crew.
Interesting Facts
- 01The aircraft was named Mokusei-go, which translates to Jupiter.
- 02The aircraft was built in 1947.
- 03At the time of the crash, the aircraft was leased from Northwest Airlines.
- 04The flight was operating in marginal weather conditions approximately 62 miles south of Tokyo.
- 05The aircraft was not equipped with a cockpit voice recorder or a flight data recorder.
- 06All 37 people on board, including 33 passengers and 4 crew members, perished.
Known Controversies & Unanswered Questions
Withholding of ATC Evidence
Reference ↗The Japanese investigation committee was unable to reach a definitive conclusion because the Allied occupation authorities refused to provide the tape recordings of conversations between Haneda ATC and the flight crew.
Conflicting Reports of Initial Survivors
Reference ↗Some unofficial accounts claim that between 20 and 50 passengers survived the initial impact but died from injuries and exposure. However, these claims are numerically inconsistent with the official manifest, which recorded only 37 total people on board.