I recently read this documentary literature – 墜落の夏 日航123便事故全記録, which records every aspect of the Japan Airlines (JAL) Flight 123 disaster in great detail, leaving me with many deep thoughts.

Regarding this air disaster, the explanation on Wikipedia introduces the process and cause of the accident very comprehensively. Here is a summary of the outline— The Japan Airlines Flight 123 disaster was an air crash caused by the detachment of the tail due to improper maintenance on a Japan Airlines flight from Tokyo Haneda Airport to Osaka Itami Airport. On the evening of August 12, 1985, at 18:56 Tokyo time, JAL’s Boeing 747SR-46, carrying 509 passengers and 15 crew members, crashed into the ridge of Mount Takamagahara near Ueno Village, Tano District, Gunma Prefecture in the Kanto region (about 100 km from Tokyo). Despite severe delays in the local rescue operation, four women miraculously survived 17 hours after the crash, including an off-duty flight attendant, a mother and daughter, and a 12-year-old girl. The remaining 520 people (including 21 non-Japanese passengers) all perished, including the famous singer Kyu Sakamoto and a pregnant woman. Because the crashed Boeing 747SR was a short-range, high-capacity model dedicated to Japanese domestic routes, and adopted a very high proportion of Economy class seating configuration, the number of passengers was far higher than general aircraft of the same class, making this air disaster the deadliest one involving only a single aircraft in the world.

Below are a few key points from the book recorded here.

1. After the accident occurred, the aircraft lost most of its vertical stabilizer, APU, and all hydraulic control, rendering the elevator, ailerons, and rudder completely inoperative. Under such extreme conditions, the crew still managed to control the flight for 34 minutes, which is incredible. They first attempted to lower altitude by reducing engine thrust while suffering from hypoxia due to high-altitude decompression, but this had no effect. They then had to rely on gravity to lower the landing gear, which finally allowed the altitude to drop. Without ailerons and elevators, the aircraft could not maintain balance. For thirty-some minutes, the fuselage continuously swayed up, down, left, and right—known as a Dutch roll—and they could only maintain balance by finely adjusting the thrust of the four engines. After the landing gear was lowered, the aircraft’s altitude dropped too quickly. Having no other choice, the crew used electrical power to lower the flaps. Due to the lack of hydraulic pressure, it took a very long time to lower the flaps; reaching the Flap 5 position took 5 minutes, and another 3 minutes for Flap 10. After the flaps were lowered, the aircraft’s altitude increased, but it began to Stall, so they had to retract the flaps again. However, at that time, the aircraft had reached mountainous terrain, and eventually lacking sufficient altitude, it crashed into the ridge of Mount Osutaka.

"Japan Airlines 123 route English" by Japan_Airlines_123_route.png: Eluveitie derivative work: Gauravjuvekar (talk) - このファイルの派生元: Japan_Airlines_123_route.png . Licensed under CC 表示-継承 3.0 via ウィキメディア・コモンズ.

The appearance of the Dutch roll is like this:

2. Collecting the remains of the victims took several months. Because the victims’ remains were incomplete, the management numbers used for the collected remains reached six digits. At the time, DNA identification technology did not exist, so identification work was extremely difficult. Medical records of the victims were sent to police stations from all over the country to assist in identification. Police went to the homes and workplaces of the deceased to obtain fingerprints and toe prints. Fingerprints from water cups, notebooks, and even toe prints left on furniture became targets for collection.

3. After the disaster, JAL assigned a dedicated employee to each bereaved family. They stayed with the family every day, specifically responsible for the family’s dietary needs, investigation and identification of remains, farewell ceremonies, burial, and other funeral affairs. According to Japanese customs, a religious ceremony must be held forty-nine days after death for the funeral to be formally concluded. Therefore, JAL employees accompanied the bereaved families until the 49th-day ceremony, and the company covered all expenses.

4. To handle compensation for the families, a specialist was also assigned to each family to help with various post-mortem procedures, insurance, and the signing of compensation contracts. They visited the families’ homes daily, listened to their complaints and demands, and helped them through the difficult times.

5. The aviation insurance industry is highly internationalized and is a global network. All aviation insurance in the world is part of this network, and the compensation amounts are jointly covered by all participating companies. Therefore, the amount estimated to be paid by Japanese insurance companies in this disaster is only a few billion yen, while the estimated total amount is over one hundred billion yen.

6. Boeing’s maintenance was highly irresponsible, and the Japanese aviation authorities’ inspection of the repairs was merely a formality, leading to irreparable losses.

Recent Investigation Report http://www.mlit.go.jp/jtsb/kaisetsu/nikkou123-kaisetsu.pdf