■ Host: Anchor Lee Hyun-woong, Anchor Han Ji-won
■ Starring: Lee Young-joo, Professor of Fire and Disaster Prevention at Kyungil University
* The text below may differ from the actual broadcast content, so please check the broadcast for more accurate information. Please specify [YTN News Special] when quoting.
[Anchor]
We will continue to update you on the aircraft accident at Muan Airport in Jeollanam-do with experts. Lee Young-joo, a professor of fire and disaster prevention at Kyungil University, is here. How are you? A plane accident occurred at Muan Airport in Jeollanam-do yesterday. Except for the rescue of two crew members, all were confirmed dead. What do you think is the reason why the casualties are so large?
[Lee Young-joo]
As it's most well known, basically, airplane accidents don't happen very often.This is because Ma is a type of accident that causes many casualties once it occurs. There are also parts that are attributed to such basic characteristics. However, in the case of this accident, it attempted to land the fuselage in an emergency situation, and the process of landing the fuselage, so it did not stop during this sliding process, and it immediately collided with the fence, leading to a fire explosion. If this is the case, it's an emergency situation in the process of the plane landing. And in fact, there was no room for passengers in this room to evacuate or to avoid danger by doing something about it until it actually slipped and then collided and led to a fire. Therefore, it was rather exposed to fire explosions. And as the explosion was formed strongly in a very short moment, there were already many casualties to the extent that suppression or rescue work itself was meaningless. I think it's right to look at it like this.
[Anchor]
Anyway, the collision with the outer wall and the subsequent fire. These two seem to be the cause of increased casualties, so which of the two do you see as the more fatal cause?
[Lee Young-joo]
First of all, the fire explosion was caused by the collision, but if the direct cause is any case, the situation in which the people inside were exposed to such strong flames and such situations due to the explosion and fire was actually the main cause of many casualties.
[Anchor]
Flight recorders and voice recorders will be collected and analyzed, but what should we focus on here?
[Lee Young-joo]
Basically, there was a problem in the process of trying the first landing, and it's common to turn around again and then land after having safe enough situations, but I think there must have been a reason for the decision. So, as you said, the reason for this is that we can fully grasp the communication contents of voice recorders, communication contents, and communication between the captain and the bookkeeper, so it seems important to check the process of identifying what factors and risks occurred in such an urgent situation. One of the most talked about in various investigations is that the landing gear didn't work anyway. However, the reason why the landing gear did not work is that in the case of landing gear, even if there is a problem on one side, the hydraulic system on the other side operates so that it can operate normally even if one is in trouble, but it was a dangerous situation where both were forced to make a fuselage landing when both were not working.
[Anchor]
As you said, many people are complaining about the part where the landing gear did not come down. If you analyze the flight recorder, can you find out whether only one engine was alive or both were dead?
[Lee Young-joo]
Yes, it will be possible. It's definitely possible. And because it is possible to roughly check whether the main systems are operating normally. On the other hand, the pilot or captain who recognized the signs of abnormality in these things mentioned these abnormalities in the process of communicating with the control tower and would have been controlled accordingly. I think that parts of these situations can be confirmed.
[Anchor]
If such a part is impossible to operate due to electronic device records, there is a way to lower the landing gear manually, so should I say that this was so urgent that it was impossible?
[Lee Young-joo]
It could be considered impossibly urgent. On the other hand, it can be said that it did not work even though it was manually landed. So now, it's very difficult for aircraft officials to do things about these systems. There must have been some backup systems or manual operations that are difficult to infer. In a way, it is quite unusual that the landing gear did not work because all of these things did not function properly. So, in a way, this part needs to be clarified a little more clearly.
[Anchor]
Muan Airport has only one runway, and depending on the direction of touchdown and landing, we call it runway 1 or runway 19. Witnesses say that the radius of rotation was narrow because it turned from the direction it was previously trying to get off and changed from 1 to 19. What should be considered as the cause?
[Lee Young-joo]
So, the most basic thing to do here is to come back down to Runway 1 after the normal situation is back down to Runway 1 if these parts turn again in the process of landing in the direction of Runway 01. In fact, this was not done like this, but there was a process of getting out of runway 1 and leading directly to runway 19 in a different direction, and actually trying to do the second landing without enough turning radius or time. Therefore, there are many experts who assume that there was enough emergency to try landing in such a hurry rather than simply a mistake by control or a mistake by control. In fact, it seems necessary to put these things together, such as flight recorders and voice recorders, and to look into what kind of emergency these judgments were made at the time and whether these situations were made.
[Anchor]
Now, in the process of turning around in such a small radius and coming down to runway 19, of course, we need to figure this out more.From the previous screen, there are rumors that the area near the touchdown was not the end of the runway, but the middle point. As a result, there are talks about not being able to use all of the 2,800m runway, so what do you think of this?
[Lee Young-joo]
This, as you said, has some truth in the criticism that the plane's touchdown as you said and the location of the plane touching the ground at first was not actually enough to use the runway. However, the argument that the runway should have been made longer because of these parts should have been considered a little differently. It's hard to get to the logic of securing a runway long enough to be safe no matter where you fall. In the case of Muan Airport, the runway length is 2,800 meters, which meets the length of the runway required by the international airport for medium-sized planes to get off, so there was a problem with the length of the runway itself because it was not just about taking off and landing, but because it was a length that fully considered safety factors that could arise during the process of taking off and landing. It is hard to say this. That's what I think.
[Anchor]
And didn't you try to land the fuselage this time as the landing gear broke down and the landing gear broke down? Was there any other way than a fuselage landing?
[Lee Young-joo]
In fact, if it was actually another way, it would have been a situation where you had to take a detour or try to land somewhere else, in a safer environment. But anyway, if the landing gear was not working, it seems that in some circumstances, it would have been a situation where the fuselage landing was inevitable. However, the problem is that even if you land on the fuselage, you could have had enough time to secure safety and prepare for the fuselage landing to land, but anyway, given the circumstances that were very urgent, there must have been such factors. I told you earlier that I'm estimating it. On the contrary, before such a fuselage landing, most of them are forced to release some fuel or continue to fly around to consume fuel, reducing the proper weight, the proper weight required for a fuselage landing, and the risk of fire that may occur in such a fuselage landing. Therefore, if it is a way to reduce the risk of these parts, it is possible that they may have used up a certain amount of fuel while flying around and then landed, but most now expect that they were not actually done enough to take action on those parts.
[Anchor]
In any case, if you make a fuselage landing without the landing gear spreading, you have no choice but to use them to stop the resistance of the wind, the resistance to the ground, and the frictional force to the ground. What many people are curious about while looking at the screen is that the front part of the plane with the cockpit should have been lowered to increase the frictional force with the ground. On the other hand, it was a pilot's manipulation to increase drag. You're saying that, but what part do you see it in?
[Lee Young-joo]
First of all, it is confirmed that the speed was quite fast at the time of the fuselage landing. In addition, witnesses are also saying in common that they slipped quickly without slowing down. In fact, if the proper speed for landing and landing the aircraft, in the case of a medium-sized plane that had this accident this time, the speed should be maintained at about 130 kilometers per hour and about 140 kilometers per hour. Perhaps because there was a problem with one engine, there was a process of landing while balancing with only one engine, so there is a possibility that the speed was raised a little more. Most pilots say that these things were not careless, but rather normal driving skills. Therefore, if the speed is higher than usual and some control was made to increase the resistance of these parts in the process of landing on the ground, I think it would have been the same type of landing situation as it is now.
[Anchor]
And now, we have to entrust the investigation to the U.S. National Transportation Safety Commission. Some are raising the possibility that the data on the flight recorder may have been damaged, and I wonder how long it will take to decipher the black box.
[Lee Young-joo]
First of all, it was confirmed that both of the recorders were collected today, and then it was known that some of the devices had some variations.In the case of dry black box devices, even when exposed to extreme environments, falls, explosions, or strong flames, the functions of the parts for record storage must be maintained, so the heat resistance and impact resistance are very high. In particular, in the case of heat resistance, it is possible to withstand this for more than 2 hours at almost 1,100 degrees Celsius. On the other hand, even in the case of brain shock, it can actually withstand 3400G, or 3,400 times the gravity, so even if the appearance is partially deformed, I don't think there will be much problem in decoding these parts and records. However, the time to read these things is important, but the process of synthesizing information on various situations with this read record and interpreting these parts by experts. From these perspectives, it is actually likely to take a lot more time than the quick results we expect. So, in general, the results of aircraft accident investigations take a lot of time because they require verification compared to other accident investigations. Looking at previous accidents in Guam or other overseas, I think it will probably take a lot of time because it takes at least a year or two or as long as three years to wait for the results of the survey.
[Anchor]
In a way, it could be a similar resolution question. Shouldn't the airline, control, and airplane manufacturers be put into this cause?
[Lee Young-joo]
That's right. So, as I said before, the things that require a lot of verification and analysis are whether there are any problems with the plane itself, whether there are any problems with the operation of the plane, various management problems, and various variables at that time. Since we have to comprehensively judge whether there have been human defects, airlines, related agencies, airplane manufacturers, and various organizations related to maintenance are interested and directly involved. That's why it's actually very difficult for each institution in these areas to make sufficient verification or convincing conclusions from their respective positions. That's why it takes a lot more time to do this.
[Anchor]
We delivered the accident process by time graphically, but if you look at it now, many people couldn't land right away in the first landing stage. And since you have questions about why you couldn't operate various braking systems, including landing gears, manually, we hope to find out the cause as soon as possible. That's all for today's talk. I was with Lee Young-joo, a professor of fire and disaster prevention at Kyungil University.
Thank you.
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