It has been one week since the accident in which a Ground Self-Defense Force helicopter disappeared around Miyako Island in Okinawa Prefecture. Searches by the Self-Defense Forces and the Japan Coast Guard are continuing, but no strong clues have been found that will lead to the discovery of the members.
We asked Mr. Koichi Isobe, a former army general who served as a helicopter pilot in the Ground Self-Defense Force, about how the accident happened and the factors that have been pointed out so far.
What is the malfunction of the aircraft?
In past aircraft accidents, there have been cases where the cause was a malfunction of the aircraft itself.
Regarding the possibility that a malfunction occurred in the aircraft this time, Mr. Isobe said, "In the past, there have been accidents in which engine trouble occurred during flight or rotors came off, causing the aircraft to lose lift and fall. In the case of aerial disassembly, the aircraft is damaged more severely, so it is not like something happened in the air and it disintegrated and fell."
Regarding the possibility of engine trouble, the company said, "This helicopter can continue flying by transmitting power to the main rotor with the other engine even if one engine stops.
"Even if the engine and other power systems stop, the helicopter can descend naturally. If you try to make a crash landing, the pilot should notify the control tower. In the absence of that, something very sudden must have happened."
What is the man-made problem?
In some past aircraft accidents, the cause is that the pilot fell into a state called "spatial disorientation" in which he could not correctly recognize the attitude of the aircraft.
"I can't say it's completely zero, but it's hard to think about it because it's daytime and there are two pilots on board, and if one pilot becomes disoriented, the other pilot will immediately take control and stabilize the aircraft."
Bird strike or lightning?
In aircraft accidents, accidents can also occur due to weather conditions such as bird strikes and lightning, in which birds are sucked into the engine.
"The possibility cannot be ruled out," he said, adding, "Helicopters have relatively small engine intakes compared to passenger aircraft, and there is a transparent windshield in front of the pilot, but if a bird hits it and breaks it, I think it will cause considerable damage. If the pilot itself is injured, it can be difficult to fly, but they are also on guard and collisions with birds are not so common, so it is not a rare case."
Regarding the effects of lightning, he said, "It is difficult to say whether the lightning strikes will not have such an impact or whether it will have a fatal effect, but there are not many large mountains and cliffs around Miyakojima, and it is difficult to think that the weather changed suddenly in the weather conditions of Miyakojima at that time." It shows the view that lightning is unlikely to have fallen.
The Ground Self-Defense Force explained that the weather conditions at that time were ▼7 meters per hour from the south, visibility was more than 10 km, and the height of the clouds was about 600 meters, so there were no particular problems in flying.
Denying "possible attack" etc.
On the other hand, regarding this accident, there are opinions on the Internet and SNS that it may have been attacked from abroad or interfered with by electromagnetic waves.
"When a helicopter is attacked by a missile, the aircraft explodes without retaining its original form, ignites the fuel, and a fire occurs. There is also a loud noise, so anyone nearby can tell it. Some of the recovered aircraft are almost uncharred, and missile attacks can be almost eliminated. Electromagnetic attacks can also be understood at that point because various things such as radios in nearby houses are damaged. If there is no such contact, we can eliminate it."
On top of that, he said, "Aviation accidents are accidents, and it is important to investigate the cause, and the first step in investigating the aircraft is to promptly recover it."