What the Nikko Crash Accident Investigator wrote in page 100: August 12, 19:16

It's been 35 years since the crash of Nikko Jumbo, which killed 520 people. NHK has obtained the notes of the accident investigators who investigated the site. The memo, which has been regarded as an internal document only for investigators, stated that it was not mentioned in the accident investigation report, and that the feelings and the cause of the accident when the site was first seen were approached at an extremely early stage. ..

It has been 35 years since the accident in which 520 people were killed when a Jumbo aircraft of Japan Airlines crashed in the Osutaka ridge of Gunma prefecture in 1985.

Regarding the accident, an accident investigation report was published two years later, in 1987, which was mainly due to the breakdown of the pressure bulkhead due to a repair mistake by an American manufacturer.

After the report was released, the accident investigators reviewed the process of the investigation and put together a note of about 100 pages to save for the future.

The memo is an internal document only for accident investigators, and NHK has obtained it from the concerned parties this time.

The cause was approaching within 2 days of the accident

The materials I obtained this time describe what the investigators thought of on the scene at that time, and sentiment that was not recorded in the investigation report.

From there, it was found that the cause of the accident was approaching within two days of the accident.

Don't panic

Hiroshi Fujiwara (92), who was a junior investigator at the time of the accident, received a phone call from his home on the night of August 12th.

Mr. Fujiwara told himself that he should not be in a hurry and wrote that he ran a bicycle to the nearest station and went to work.

When Mr. Fujiwara arrived at his workplace, it was confirmed that the NISS had crashed and a fire had occurred, but he did not know the exact location of the point.

Japan Airlines and the Civil Aviation Bureau of the Ministry of Transportation at that time headed for Nagano Prefecture with fragmentary information, but Mr. Fujiwara and others predicted that the roads in the mountains would be limited and could not move, so they moved until the crash point was found. I will judge that there is no.

As a result, he was able to rush to the scene of the accident as quickly as possible, and Mr. Fujiwara recalls, "It was the correct answer to not move blindly."

It's the first time in a field like this

The next morning (13th), Fujiwara and his friends saw the scene for the first time with a helicopter from the sky.

At that time, one of the investigators frankly wrote, "I have seen various accidents, but this is the first accident site where the broken shape is so bad that the shape of an airplane does not remain."

Critical testimony obtained extremely quickly

About the time when the information that four survivors were found came in, it was described as "an incredible event for all investigators."

Fujiwara and his colleagues immediately send investigators to the hospital.

It is said that the senior of the acquaintance of the investigator who went to the hospital accidentally worked at the hospital and was able to listen to the survivors on the same day.

The survivors were the flight attendants of Japan Airlines who were boarding as passengers, and the content of the testimony was that there was a sudden decompression in which the air pressure inside the cabin suddenly dropped, which was extremely serious and directly related to the cause of the accident.

About that time, he said, "I was fortunate to have an important dictation at an early stage, which helped me in my subsequent research. It was a great achievement."

Significant evidence obtained in the field

On the second day (14th) of the accident, he walked into the scene, and saw Mr. Fujiwara piercing the dismembered wing members, saying, "The stringer on the main wing is stuck in a lot. It's an odd sight. Is spelled out. At this time, Fujiwara and his colleagues discovered that a large amount of insulation material in the cabin had entered the horizontal stabilizer.

Mr. Fujiwara and his colleagues speculated that there was a possibility that a facility called a pressure bulkhead, which keeps the air pressure inside the cabin, might have been broken, based on the testimony that there was a sudden decompression and the situation that the insulation inside the cabin was jumping out of the cabin. Did.

You can see that the cause of the accident, announced two years later, was approaching in just two days.

Some things I couldn't find out

In this accident, the pressure bulkhead, which keeps the pressure in the passenger compartment constant, suddenly broke and air suddenly blew out to the rear of the passenger compartment, causing more than half of the vertical stabilizer to be lost, making it difficult to maneuver.

Two years later, the aviation accident investigation committee at that time published an accident investigation report, and the main cause of the accident was a repair error by an American manufacturer made at the time of the Shirimochi accident that occurred 7 years before the accident. it was done.

However, it was impossible to investigate why a repair error occurred without the cooperation of the United States.

In a note, Mr. Fujiwara said about the repair mistake, “Why did you make such an insane connection method. From the common sense of engineers, it is tempting to assume that there is a high possibility of “carelessness”, but the worker himself I don't even remember it."

Mr. Fujiwara said, "Why I made a mistake in repairing, I have not been able to find out the cause until I received the answer to the end no matter how many times I contacted the United States. I think that I will be forced to carry it for life even if I receive criticism about it." I was talking.

Former investigator "Don't forget the accident"

Mr. Fujiwara has given a lecture on accidents to contribute to the safety of aviation even after retirement and has continued to climb memorials at the ridge of Osutaka, the site of the accident.

"I happened to be in the position of accident investigation at that time, but it was the biggest and most shocking accident in my life." "I wrote the internal document because I wrote about how the investigation was conducted and the situation. 35 years have passed, and we thought we could make it public if it would be useful to you."

“It's important to remember the accident and go back to the beginning, whether it's the best thing you're doing right now, or always reflect on what you're doing. Is there a better way than it is now? There must be a safer way. If so, I think it will open the way.” He emphasized the importance of keeping people involved in safety efforts.