"Mayday, Bird Collision" Communication Revealed...launch a joint investigation into the black box

■ Host: anchor Lee Hyun-woong, anchor Cho Ye-jin
■ Telephone connection: Jeong Yun-sik, Director of the Department 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 News START] when quoting.

[Anchor]
Just before the accident, some of the communications between the control tower and the pilot were released. Pilot referred to 'bird collision' with 'Mayday' distress signal The black box of the accident machine has also been analyzed in earnest. Let's point out the questions that need to be solved one by one with an expert. Let's connect Jung Yoon-sik, head of the Department of Aviation Operations at Catholic Kwandong University. Professor, you're out, right?

[Jung Yunsik]
Hello.

[Anchor]
Some of the communications released yesterday were released. At 8:57 the control tower warned of bird activity and 2 minutes later the pilot declared Mayday referring to the bird collision, what should we note from this communication?

[Jung Yunsik]
Because they used the term Bird Strike among their current communications and notified the control tower of it, it is believed that the pilots are aware that the aircraft has struck a new one. I don't know if I saw the actual collision or if I saw a bird passing by, but I think I found out that I crashed into a bird and felt an abnormality in other engines or an aircraft impact.

[Anchor]
It's still a family.Assuming that a bird is sucked into the engine and there is an engine failure, it is not all that the engine fails immediately even if the bird is sucked into the engine. Is there a possibility that a bird collision took place before the control tower bird warning?

[Jung Yunsik]
There's a good chance. In terms of time, if the current crashes and the engine is damaged, there is a possibility that the engine instrument changes in 0.1 second or the impact causes engine vibration, but the engine power is very low because it is currently approaching. This is because you don't usually need that much output when you approach it. So, if you know the actual change in the trigger and understand that the bird collision occurred, it is possible that the bird collision may have occurred in advance before the control tower was warned that there were many birds.

[Anchor]
What I'm curious about is that all engines are damaged by a bird collision, and problems such as landing gear and wing flaps can occur at once?

[Jung Yunsik]
It is quite difficult for a bird to hit and cause a malfunction or stop working, such as a flap, a lift. However, when the engine stops, both the hydraulic pump by the engine stops, stopping the landing gear or the pump that prevents the flap or such operation, so the flap or landing gear may not actually be operated by the engine. However, there are videos of the landing gear folded back up and the flap was raised back up at the time, so the hydraulic pump was operating normally and the engine was not completely perfect, but it actually operated to some extent and generated some output.

[Anchor]
As the professor just said, the front wheels appear to be operating normally at the time of the first landing attempt, even by the photos and videos of the witnesses. However, the landing gear was not unfolded in the second landing attempt. Let's see the results of the investigation.What kind of problem do you think Ma may have encountered?

[Jung Yunsik]
The reason why the landing gear was not lowered is because the actual pilot operated it, but it did not work, or whether it was intentionally lowered because it was judged that it was better to not lower the landing gear and try to land the fuselage in the current state, but if you see the data on the aircraft, it does not actually rise, that is, it does not appear to increase the plane by increasing the output. That means that both engines are difficult to operate, so it is actually impossible to lower the landing gear or flap accordingly.

[Anchor]
Even if there is an engine problem, there will be auxiliary power devices and there is also a way to manually lower the landing gear. Was there a lack of time?

[Jung Yunsik]
That's right. It takes only about a minute and a half to two minutes to go back to the other side, that is, to get to the end of the north runway, turn the plane around from there, and ground it. Because of that, the time is very short. It takes at least 30 seconds per unit because it takes three separate times to manually lower the landing gear, and two separate nose and main gears. Then, it takes more than 1 minute and 30 seconds to get down three, so the assistant manager will probably intentionally lower the landing gear because he cannot give any flight assistance to the captain or assist other operations in order to operate the three. If you get off only one side or the other two sides fail to get off due to lack of time while getting off, there is a possibility that the plane will become more asymmetric and become more dangerous when landing. So there's a possibility that they didn't get off on purpose.

[Anchor]
We need to see the results of the investigation whether it didn't work properly when we got off, or whether it was better not to get off based on the judgment of the captain and the bookkeeper.

[Jung Yunsik] It's
right.

[Anchor]
It is said that the accident aircraft has completed 13 flight schedules in two days. What do you think about the possibility of gas damage due to unreasonable schedules?

[Jung Yunsik]
I don't think it's too much to say. Airplane fatigue and stress management are managed by flight hours. In other words, when the time comes, for example, the aircraft is maintained for 100 hours, and when the time comes, the aircraft is maintained for 400 hours, 600 hours, and 1000 hours, so if you operate a lot of time, the maintenance time will eventually arrive quickly. Others do it for two hours a day, so if we do 100 hours in 50 days, we get to 100 hours in 10 days, so we start maintenance again at that time, so we end up continuing the maintenance normally. So, if you operate a lot, other people will only use a plane for 30 years and dispose of it for 10 years, so it seems that there is no big problem because it is ultimately a time-based maintenance system. Then it's about the quality of maintenance. I think there will be no problem because the aviation authorities are always monitoring these issues, such as whether they have been properly maintained or whether parts have been replaced for maintenance.

[Anchor]
Looking at the schedule alone, it is difficult to say that it is an unreasonable schedule, but it seems necessary to check whether it has been properly maintained. Bird collisions are now being cited as one of the main causes, and there are reports that there was only one bird eradication team at the time of the disaster. It is known that many migratory birds always fly around Muan Airport, and one bird eradication team works. Do you think this was appropriate?

[Jung Yunsik]
Since Muan Airport is not an airport where there are frequent flights, for example, there is only a bird eradication activity at the time of flight, landing, or takeoff. However, if the plane is always flying, there should be a lot of batsmen who are engaged in bird control activities, but if it is actually needed at the necessary time, it may not actually require a lot of people. However, if there were so many actual bird activities that the control tower warned about, I think it would have been better to increase the number of people.

[Anchor]
Is there any technology that makes noise on its own in an aircraft rather than chasing birds by personnel outside the aircraft?

[Jung Yunsik]
There is no such thing yet. Even birds don't have large spaces that they can avoid or things like that. And in reality, the speed of the plane predicted by the bird is much faster than it looks. The bird can't predict that the plane will come quickly. That's why you're looking at it and when you come closer, you're going to avoid it, and then you bump into it Or because there are multiple birds at the same time, it's like a bird hitting the end while avoiding it, so actually seeing it in advance and avoiding it is actually very difficult, especially to see a bird in the cockpit. In particular, seeing birds from above the land is difficult because of the similar colors. In particular, the bird goes down if it hits. So pilots are also trained to lift their riders up in the event of a collision.

[Anchor]
Muan Airport is one of the airports where there are a lot of bird collisions among domestic airports, so I think it's more regrettable. There are new cluster areas around, and there are also comments about whether it is appropriate as an airport in the environment. Do you think we need to review it again in this situation?

[Jung Yunsik]
Initially, the airport itself may not have been an area of algae. However, as airports are developed in large areas and around them, airports with large open spaces and lawn areas where they feed naturally become bird habitats. So, if you actually build an airfield, the airfield itself becomes a bird habitat, so it's safe to think that birds are gathered.

[Anchor]
One of the other causes this time is bluntness. Landing-guided safety facility, why is there a mound under the local riser?

[Jung Yunsik]
Dundeok can be seen as a floor support to build an antenna. Since the location is actually about 3 meters up, I think it has a lot of influence on the actual collision and caused a fire on the plane. I don't see this as an obstacle because it's made of navigation safety facilities and flight safety facilities. However, although there are some data that actually satisfy the requirements but are not satisfied with the other additional requirements, this does not seem to be a big problem when the airport is in operation. It is believed that this was judged as an underground facility. Underground facilities. That's why we believe it's not a big problem.

[Anchor]
Of course, it can be seen that there is no problem with various aviation regulations, but since accidents are not always predictable, should we think about ways to eliminate concrete facilities such as dundeok when we prepare in various aspects?

[Jung Yunsik]
That's right. There's no problem with the regulations, but isn't there a good chance that we can predict that this will happen again in the future? Then you can get rid of this concrete and turn it into an iron frame, a thin frame, or even take this opportunity to cover the slope at the end of the runway and hit the height with the soil. Also, I think it is necessary to find out if there are any of these not only at Muan Airport but also at other airports, and check them once to improve safety.

[Anchor]
I see. The black box has been collected and an investigation has been launched. It was last night. Officials from the U.S. Transportation Safety Regional Bureau and Boeing will also enter the country and investigate together. It is said that it will take at least a month to detox now, what do you think should be focused on?

[Jung Yunsik]
In the voice recorder, the first thing that pilots should know is what decision the captain, assistant manager, or captain made and what action they ordered. For example, I think the first thing to do is to understand whether you got off the landing gear, but you didn't get off, or if you couldn't act properly because of noise or something, or if you got off and didn't get off, and then analyze the data of the flight recorder according to the contents. Since it is said that it has been damaged for a while, it is possible to extract each data in detail again. Then, there is a possibility that it will last up to three to four months.

[Anchor]
Various aircraft operation processes will be recorded in the black box, but can you check if there are parts that manually operate the landing gear?

[Jung Yoon-sik]
Yes, you can check that, and especially since even small sounds are recorded in detail on the voice recorder, instructions for the pilot to lower the landing gear by manual can also be recorded. You can even hear the sound of opening the landing gear cover, so you can check whether it's actually operated or not.

[Anchor]
I see. First of all, we'll look at the results of the investigation. Let's stop here. I was with Jung Yoon-sik, head of the Department of Aviation Operations at Catholic Kwandong University. Thank you, professor.

[Jung Yunsik]
Thank you.