Japan Air Lines Unzen emergency landing

The Japan Air Lines Unzen emergency landing (Nihon Kōkū Unzen-gō fujichaku jiko) was an aviation accident that occurred on 30 September 1957 (Shōwa 32).

Information on the accident aircraft

The accident aircraft, JA6011, had been given the nickname “Unzen”. At the time, Japan Air Lines gave its DC-4s nicknames taken from famous Japanese mountains. It had manufacturer's serial number 42982, was built in 1946 (Shōwa 21), and had been operated by Capital Airlines in the United States. Its registration at that time was N53022.

In April 1956 Japan Air Lines purchased it for about 700,000 US dollars (252,000,000 yen at the exchange rate of the time) and refitted it to a Japan Air Lines configuration with 61 seats. By the time of the accident, the Unzen had been in service for 11 years and had flown 30,906 hours 23 minutes, which was not particularly old for a second-hand aircraft.

Course of the accident

On 30 September 1957 (Shōwa 32), the Unzen was operating round trips between Tokyo International Airport (Haneda) in Tokyo and Osaka International Airport (Itami) in Osaka, and at the time of the accident was scheduled to fly from Osaka to Tokyo as Flight 108. On board the Unzen were 2 flight crew, 2 cabin crew and 51 passengers. Among the passengers was the jazz critic Ayurō Miki. It was also carrying 49 bags (305 kg) of air cargo and 27 mail bags (160 kg) entrusted by the Ministry of Posts and Telecommunications.

The scheduled departure time of Flight 108 from Itami was 8:25 pm, but because the outbound leg had been delayed for air traffic control reasons, it took off at 9:36 pm, 1 hour 10 minutes behind schedule. However, immediately after take-off the No. 1 engine on the left wing stopped, and the other 3 engines also began to malfunction. As a result the aircraft went into a stall. In this emergency the captain judged that it was impossible to return to the Itami runway and decided to make a forced landing. At around 9:40 pm the Unzen made a forced landing in a paddy field at Katsube, Toyonaka, which lay on the extended centreline of the runway, but because the aircraft caught on power lines and was damaged, it slid on while burning. Thanks to the swift evacuation guidance given by the cabin crew, although 3 passengers were injured by the impact, all were able to escape safely. This evacuation guidance was praised. The 2 flight crew were also seriously injured, but the Civil Aviation Bureau of the Ministry of Transport praised the captain's decision as correct, stating that had the aircraft tried to return to the airport it would have crashed on the way.

Accident investigation

According to the Ministry of Transport's accident investigation, there was an abnormality in the accident aircraft's crossfeed valve, the supply of aviation gasoline from the fuel tanks was interrupted, the engines failed, and the aircraft stalled. The Osaka District Public Prosecutors Office decided not to indict the captain, finding no suspicion of negligence, so no criminal action was taken.

Aftermath

Japan Air Lines received from the insurance company 240,000,000 yen in insurance money for the total loss of the aircraft, and also received 5,000,000 yen in compensation costs for the passengers and for the landowners whose rice, not yet harvested, had been damaged. As replacements for the Unzen, which was completely destroyed in the accident, Japan Air Lines in February 1958 (Shōwa 33) purchased 2 second-hand DC-4s from airlines outside Japan, the Asama (JA6014) and the Amagi (JA6015).