[News Now] Jeju Air's investigation into the truth...What's the growing question?

■ Host: Kim Sun-young Anchor, Jung Ji-woong Anchor
■ Starring: Jung Yoon-sik, Professor of Aviation Operations at Catholic Kwandong University

* The text below may differ from the actual broadcast content, so please check the broadcast for more accurate information. Please specify [YTN NewsNOW] when quoting.


[Anchor]
It's been three days since the Jeju Air plane crash, but questions about the situation at that time continue. The cause of the accident is also being investigated in earnest. Let's talk about this with Jung Yoon-sik, a professor of aviation operations at Catholic Kwandong University. Welcome. Various analyses of the time of the accident continue to emerge, and several other questions are being raised. So, after the first attempt, it was repeated again and the second landing was made, but during the first attempt, there were claims that the landing gear was down.

[Jung Yunsik]
In the case of the first approach, the instrument approach procedure was normally lowered. So if you look at the contents, the speed is reduced to the final approach speed. That means you can't slow down unless the landing gear and landing flap are all down. That's why it's all down, and when you repeat it, you basically raise the aircraft first and put the landing gear first. So the landing gear means, didn't all the hydraulic pressure and fly control work normally at that time? Until then. I'm looking at it like this.

[Anchor]
It's only a few minutes from the 2nd try, so just a few minutes ago, are you saying that the engine was working properly?

[Jung Yunsik]
That's right. The engine may be partially out of order, but anyway, even if the engine operates at low RPM, the hydraulic pump operates, so it would have been possible to fold the landing gear or flap right away.

[Anchor]
If the landing gear came down like that during the first attempt, why on earth would it go back up without landing in that situation?

[Jung Yunsik]
In the past, there was such a procedure. There was a procedure to get off right away from a nearby place. The procedure for getting off the two engines is very different from the procedure for getting off the two engines if one engine fails. Because there's a procedure where you have to speed up more and you have to turn the engine back off in the air and restart it, so you have to raise the altitude to 3000 or 4000 feet, and then you have to do that and come back down.

[Anchor]
You're coming down after normalizing it, right?

[Jung Yoon-sik]
Yes, but these days, when you're almost on the runway, at the airfield, and you're almost on fire, or when the aircraft breaks down, you're supposed to get off right away. In the case of only 10 to 15 seconds, it does not go around and instructs the procedure to get off immediately.

[Anchor]
It would be nice if you could show us the graphic by time zone a little while ago. So the first try and the second try. We reorganized it by time zone. The first attempt was made at 8:54 as the first landing permit for the control tower was dropped. And the bird warning signal drops. And signal transmission such as aircraft location will be terminated. And at nine o'clock, second landing attempt. So, it's a six-minute difference from the first attempt. It means that the landing gear didn't come down at that time. So, a lot of things happened in six minutes, so what do you think happened?

[Jung Yunsik]
According to that photo, the landing gear and flap are all down to position 3. As the pilot goes around after three times, the go around takes precedence over Mayday for the pilot. So I would have told you to make a decision about the go round and declare Mayday by controlling the go round. At that time, if the assistant manager had a bird collision with Mayday, there would be additional bird collisions and things like that. So, while going from position 3 to position 4, if the two engines are alive, the plane is in a light state because it's almost out of fuel.

So, the angle of elevation is very high, so it can go up very quickly. But actually, in that picture, it's almost impossible to go up until you get to position three to four. That means the engine can't generate thrust. And coincidentally, the signal to send the location of the aircraft at position 3 has ended. Didn't the algae actually get inhaled at that time? Or before that. Then both engines, because if the electricity is cut off, both engines must fail at the same time. Of course, about 30 minutes is enough for the battery, but devices such as ADSB that transmit their location are not essential equipment, so it is likely to have been blocked. As a result, short circuits and other important electronic devices are likely to be alive. The rest may have been turned off.

[Anchor]
If we assume that a bird strike occurred based on the circumstances, is there a possibility that two engines have had problems at the same time, not one engine?

[Jung Yunsik]
That's right. The difference could be a few seconds, but whether one engine was damaged by a collision and immediately became another, or was sucked in by a flock of birds at the same time, and both happened at the same time. If you look at the picture over there, the left side is also a little bit right before it just happened. Let's take a look. Before the size happens like that, it was a while ago. It looks like that, right? Didn't both of them have already been inhaled at the same time? So, it's said that the algae are inhaled, so the engine runs at hundreds of RPM and doesn't suddenly stop. Because it basically has centrifugal force. So it's hard for a pilot to figure out in a split second that the RPM has dropped and the engine has dropped. So I think that the engine was already in bad condition at that time, but it would have been difficult for pilots to fully grasp it.

[Anchor]
When people who witnessed that moment, fishermen, and such people saw landing gear during the first attempt. And you can also see the images captured in the photos, which is consequential, but I also think it's a little disappointing what it would have been like to try to land when the landing gear came down.

[Jung Yunsik]
Aviation always has procedural problems, so if you got off right away like that, the pilot would have been punished and suspended even if he got off well. Because it violated the procedure. However, as a result, there is a regret that even if it goes wrong, it would have caused less damage to so many lives, but I think I probably did that because the procedure is to obey the law anyway.

[Anchor]
Now, if we tell you one more consequential thing after the incident, didn't the plane try to land the fuselage on about a third of the runway? I also think that the damage would have been reduced if it had been carried out a little more in front of me.

[Jung Yunsik]
That's right. A fuselage landing is a procedure in which an aircraft is erected due to friction between the aircraft fuselage or the engine part of the aircraft and the runway, so the longer the length, the shorter the speed. So it's possible that if it's at least a third past the limit, it might have been reduced, but that's how you think about it, there's less time to go back to area 4 to 5, and if you want to go back to the end of the runway at area 5, you have to go through the runway at 90 degrees. That means it's impossible to land after all. This is because the radius of the line is almost 1 to 1.5 kilometers.

Then, I think that the pilot should reduce the speed halfway through the runway or a third, but I think it will be quite difficult to slow down because reducing the speed will mean that you will lose energy and maintain your life.

[Anchor]
When explaining the situation earlier, it was said that the signal transmission was stopped. Is it common for the signal transmission to be cut off when the engine fails?

[Jung Yunsik]
I'm afraid not. It depends on which equipment is connected and which power source is connected for each model. The 737-800 is also different for each airline, so it's connected to a certain part and a system. For example, even if all the power is out, if the essential power connected from the battery is in it, you can use it until the end. However, since that is not essential equipment, it is quite likely that it has been blocked.

[Anchor]
Isn't there a way to get off manually if there is an electrical problem like the landing gear cannot go down in this situation? But what's the reason you couldn't get it off?

[Jung Yunsik]
Lowering the landing gear is basically done in the hydraulic system. If there's something wrong with the hydraulic system, it's going to have to get off manually. Isn't there one wheel in front and two main ones next to it? Put those three down separately. You don't get off all at once. So, if you bend over to the back to operate one and check that it's completely down, and then lower it again, it's supposed to take about 15 seconds per one, but if you stabilize the next lock, I think it takes about 30 seconds.

Then, you can't actually get off in 1 minute and 30 seconds. So I think the pilot will probably choose not to make that choice. [Anchor] Didn't the plane try to land 2nd time in 180 degrees now?
As you just said, the actual acceleration wasn't good enough to fly higher, so we couldn't come back in the circle direction, so we couldn't come back in the 01 direction, so we had to come back in the 19th direction that we're talking about?

[Jung Yunsik]
He decided that he couldn't go to the runway if he didn't turn around now. But actually, if you look at the contents, it's very likely that it couldn't have come to the runway if it hadn't been turned at least 10 seconds from then or there. So, it's a situation where you can't say that the judgment itself is wrong. Then, what kind of situation is there in which such manipulation can be performed? I train. When both engines fail at the same time, there is a procedure to turn them urgently and come in. Then I think I did it according to the training.

[Anchor]
At today's briefing by the Ministry of Land, Infrastructure and Transport, is it a violation of the regulations that the Dundeok and localizer facility is made of concrete? The Ministry of Land, Infrastructure and Transport claims that this is not a violation of the regulations, so what do you think personally?

[Jung Yunsik]
In terms of content, it is actually more reasonable to see it as an underground structure. Although exposed to the ground, other airports now actually have concrete structures underground because they are parallel to what is installed on the runway.

But Muan Airport is nine times as large from the end of the runway to here. The height difference is 3 meters, so it was stacked with concrete and installed on top of it. In terms of content, it's a regulation and procedure made when you don't think about whether an airplane will come there and collide, regardless of actual regulations. So it doesn't mean a debate whether those things are right or wrong, and it hasn't happened anymore? Then we have to improve quickly. Since there are places like that in Yeosu or other places, if it's really low, it's important to stack more soil quickly to match the horizontal plane, or to make concrete underground and install other supports in that area. So the Ministry of Land, Infrastructure and Transport also talked about improvement. Actually, there's a problem with saying that it's an improvement, so I'll correct it. I think it's better to accept it like that.

[Anchor]
Anyway, during the investigation process, we have no choice but to look into the regulations. The Ministry of Land, Infrastructure and Transport expressed today that it was not a violation of the regulations because it was not a longitudinal safety zone, but the term was a little difficult. What does that mean when it's a precision approach runway and when it's not, the end safe zone changes?

[Jung Yunsik]
That's right. If a runway approaches the instrument closely, it can come down invisible to a low altitude, which is called a precision approach. Basically, it's 200 feet, so even if it's cloudy up to 60 meters, you can come in without looking at the runway. Equipment has been developed that can approach almost zero feet lower. That's a high level of non-confidential approach. It's 500 feet, 1000 feet. That's because there's a lot of room to look at and modify the actual runway.

So, even if you lack the ability to enter the runway accurately, you can look at the runway and adjust it even if it is sloped and slanted, and the localizer is a device that adjusts the direction within 0.5 degrees for precise access. There should be no obstacles at the end of the runway as it comes down low to access the precision instrument. It is set to 90m and 250m and installed. The precision approach is installed wider because there should be no obstacles. The non-precision approach was installed a little short because you can see the runway at a high altitude, you can see it like this.

[Anchor]
Then, as you can see, doesn't Muan International Airport here also correspond to a precise approach runway? Then, do you think that the distance from the azimuth line facility you mentioned now, after seeing that it falls under the precision approach runway, is that correct for the regulations now? Or do you think it's a little off?

[Jung Yunsik]
There are parts that are contrary to the international content and the re-requested situation. It's true to domestic regulations. Then, the Ministry of Land, Infrastructure and Transport will determine whether it has not yet changed international regulations to domestic regulations or whether it is correct to apply our domestic standards, but domestic regulations come first anyway. Therefore, we believe that there are no major problems with domestic regulations at present.

[Anchor]
Regarding the installation of this facility, the Ministry of Land, Infrastructure and Transport said that there was no violation of regulations, and we talked about the installation of Dundeok earlier, and I think I should introduce some of the exclusive coverage covered by YTN. The Ministry of Land, Infrastructure and Transport installed the concrete structure in which the manufacturing airliner collided, as stipulated in today's briefing. According to the navigation safety facility protection manual published by the Ministry of Land, Infrastructure and Transport, local risers should be installed so that they can pass through the slope without difficulty.

In addition, the foundation of the support is stipulated to be installed on the soft ground at the same height as the ground surface, but the actual aircraft collided with a hard and high structure and exploded. In addition, the Ministry of Land, Infrastructure and Transport explained that there is no problem because the facility is outside the longitudinal safety zone, but it was pointed out that this part was also an explanation that did not meet the regulations. According to the Ministry of Land, Infrastructure and Transport's airport take-off and landing site installation standards, it is said that the point where the azimuth provision facility is installed should be extended to a longitudinal safety zone. How did you hear this part?

[Jung Yunsik]
The terms that can be interpreted may be slightly different. If we talk about the support first, the concrete facility is the support, or it appears on the screen up there and in the back. If you look at the antenna, it is not actually accurate whether the pipe standing up to the antenna is expressed as a support.

[Anchor]
It's coming out on the screen right now.

[Jung Yunsik]
Down there...

[Anchor]
Where should I look at as a support?

[Jung Yoon-sik] The support is that pipe, and you can see it as a support that's about 1m up to the top. It's a kind of weak iron, so it's not wrong to look at the support like that.

[Anchor]
The concrete in that hill is not a support, you mean you can see it like this?

[Jung Yunsik]
That's how you can interpret it. I think that's how the Ministry of Land, Infrastructure and Transport interprets it. So it's a terminology dimension of whether it's wrong or not, and the other thing about the manual is the contents of notices, rules, and regulations. Actually, that's not the law. As a result, there is probably a problem with interpretation, and apart from that, the incident has occurred now, so we need to carry out the procedure to improve quickly.

[Anchor]
You just told me, but if we want to improve it, how do we need to fix it in the current situation?

[Jung Yunsik]
Shouldn't we expand the runway longitudinal safety zone a little bit earlier? Then you have to extend the wall. In the end, it is expected that it will take a long time to extend it to accommodate the land and expand the runway, and expand the airfield. So, we need to design those things, accept them again, and make improvements even if it takes several years to make purchases.

[Anchor]
Finally, if you look at what we covered, you said that this is the azimuth provision facility in relation to the longitudinal safety zone, no, this interpretation can be divided. Then tell us how far it is desirable to set the longitudinal safety zone in the future and how to interpret and improve it.

[Jung Yunsik]
Currently, the Aviation Safety Act stipulates that Korea also follows ICAO standards. So, rather than domestic law, let's follow international law anyway. Also, up to 90m, 250m is a recommendation. If you interpret recomendations incorrectly, you can or don't have to, and this is why Korea doesn't do it, but you have to interpret them more strongly and almost do it.

However, in this case, there is a possibility that ICAO will also change its comment to a reviewer. Because it's been this long. So I think it's probably better to change it to fit international regulations.

[Anchor]
Isn't it okay to extend the regulations related to aviation safety? This can lead to major casualties in the event of an accident. You mentioned that these regulations, which are recommended, need to be strengthened in the future. This has been Jung Yoon-sik, a professor of aviation operations at Catholic Kwandong University. Thank you for talking today.