362 Jeju flight 2216 Mystery: Why Aircraft Didn’t Slow During Slide on the Runway
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I'm sure you've heard about the crash of Jeju flight 2216 that occurred earlier this week in South Korea. While there's a lot we know about the flight, there's still some very important unknowns. So at this point, it's not knowable what caused the crash. There are two videos online that show the aircraft touching down, and one of them gives a very good view of the 737 from the moment it touches down until it goes off the runway and bursts into flames.

When I first saw the video, I was struck by how the aircraft didn't seem to be slowing down after a touchdown. So three days later, I pulled the video into my video editor and began examining it frame by frame. That let me estimate the aircraft's speed at several different points along the runway, and what I found was quite surprising and not what you'd normally expect after a gear-up landing.

Today I'll talk about those speeds, what's known about the crash, the important things we still don't yet know, a few scenarios that might have led to the crash, and most importantly, what we as GA pilots can learn from this and similar crashes. Hello again and welcome to Aviation News Talk, where we talk in general aviation. My name is Max Trescott. I've been flying for over 50 years. I'm the author of several books and the 2008 National Flight Instructor of the Year, and my mission is to help you become the safest possible pilot.

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Let's talk about what's generally known about the crash of Jeju Flight 2216. First, let me say that we don't know why the aircraft crashed, but I'm confident we will eventually know the cause, as the cockpit voice recorder has been recovered. The flight data recorder was also recovered, though reports say that it has some damage to it.

As I've mentioned before, some countries investigate accidents as criminal acts. The Guardian reported on Thursday, January 2nd, that earlier in the day, police in South Korea raided Muan International Airport, as well as the offices of Jeju Airlines. In a statement, police said, quote, in relation to the plane accident that occurred on December 29th, a search and seizure operation is being conducted from 9 a.m. on January 2nd at three locations. The

The police plan to swiftly and rigorously determine the cause and responsibility for this accident in accordance with the law and principles.

The Guardian also writes, "...an official said police had banned the Jeju Air Chief Executive Kim Ibae and another unidentified official from leaving the country, calling them key witnesses who potentially face charges of causing death by negligence, which is punishable by up to five years in prison, or fine of up to 20 million won, which is approximately $13,500."

So as you can see, in addition to the accident investigators who are on scene, the police are also investigating. And now let's get to the accident.

Jeju Air Flight 2216 was a scheduled flight from Bangkok, Thailand to Muang International Airport in South Korea. On Sunday morning, December 29th, the Boeing 737-800 landed gear up on runway 19, slid down the runway on its belly, ran off the end of the runway, and hit a concrete berm that supported the localizer antennas for the ILS. It erupted in flames, killing everybody except for two crew members seated in the very back of the aircraft.

We have ADS-B data down to about 500 feet AGL as the aircraft approaches runway 1. However, we don't have any data after that. What we do know is that in the next few minutes, the aircraft flew by the airport, turned around, and crash-landed on runway 19. Here's what Flightradar24 wrote about the final ADS-B data. Based on the position of the video, it would appear the 737 was landing on runway 19 in the opposite direction of the last received ADS-B position.

This leads us to believe that the final ADS-B messages we received represent preparation for possible fly paths to the airport. This is often done to visually confirm that the landing gear is either down or not prior to making a decision on next steps. The chart below shows the altitude and reported vertical speed of the aircraft from 2,000 feet to the last signal received at 500 feet.

Looking at the chart they included, it shows the aircraft in a steady descent of about 750 feet per minute. The descent rate increased briefly to about 1,000 feet per minute. Then, just as it reached 500 feet MSL, the vertical speed spiked briefly to an 1,800 foot per minute climb, during which time the aircraft climbed about 100 feet.

It briefly resumed a descent of about 700 feet per minute, descended back to 500 feet, and then just as the data ends, the vertical speed went back to zero, suggesting the aircraft was leveling off or about to begin a climb. The data ended at 8:58 a.m. in the morning, most likely because the aircraft flew beyond line of sight from whichever ADS-B receiver in the area was receiving the signal.

Like most ADS-B websites, Flightradar24 receives data from a network of receivers installed by volunteers and aviation enthusiasts who take the time and money to install these receivers, often in their homes. Now here's a timeline that's been published for this accident. This comes from Wikipedia, and it matches what I've read elsewhere.

At 8.54 a.m., the plane was authorized to land. As the plane was preparing to land, it was warned at 8.57 about the potential for a bird strike. A minute later, it issued a Mayday Alert. Now, that would have been at 8.58 a.m., which is the exact time at which we see the brief climb in the aircraft's ADS-B data.

At 9 a.m., the plane attempted an emergency landing, being forced to go around after the landing gear was not deployed. A minute later, it received authorization to attempt a landing from the opposite direction. The crash occurred between 9.03 and 9.07 a.m. And by the way, most sources say 9.03, as the aircraft belly landed touching down 1,200 meters or 3,900 feet along the runway. And that was from Wikipedia.

Now, the runway is 2,800 meters long, which is nearly 9,200 feet. However, there was ongoing construction which shortened the runway's length from 2,800 to 2,500 meters, or to about 2,800 feet. So if the aircraft did touch down at the 3,900-foot point, then it would have had only 4,300 feet remaining.

Thus far, it's somewhat unclear whether the aircraft did a low approach to the runway, or whether it did a flyby and asked the tower to inspect its gear, or whether it simply entered the downwind for runway 19 to give themselves more time to run checklist.

Here's one account we have from the eyewitness who shot the most widely viewed video from his restaurant. The restaurant is just 200 yards from the runway and is located across from the 01 runway numbers near the crash site. In an interview that appears in yesterday's New York Times, he said, quote, Around 8.57 a.m., I hear bangs. They sounded like incomplete combustion from motorbikes, but louder and unfamiliar. I often hear guns being fired to chase away the birds."

as well as noises from different construction work. But never have I heard that kind of banging noise. I thought it was strange, so I left my kitchen and went outside of the restaurant parking lot and looked up at the sky. I saw the airplane. It was above my restaurant instead of over the runway, and the plane was tilted a bit to the right. It looked to me like the plane was about to make a landing only toward my restaurant rather than toward the runway. I have never before seen a plane fly so low over my restaurant.

I went to the back of my restaurant to watch the back of the plane. The plane was higher in the sky than when I watched it earlier, and as it descended, it was making a circle toward the right doing a U-turn. It felt like the circle was a really small one. I felt that there was something definitely wrong with this plane and that I should take a video. That's why I walked up to the rooftop. So it sounds like the aircraft made a low approach to runway 1, but was a couple of hundred yards left of the centerline as it approached the runway and began its climb out.

Winds at the time were reported as 110 at 2 knots, so a tiny crosswind, so it wouldn't have mattered which runway they landed on. Early reports say the pilots didn't state the nature of their emergency. However, there is a lot of evidence to suggest that the plane ingested one or more birds in the right engine. NBC TV of South Korea released video showing a possible bird strike in the right engine, followed by a large puff of smoke as the aircraft first approaches the airport.

Some witnesses said they saw a flock of birds being sucked into the right engine, causing a fire. And a passenger sent a message to their family before the crash saying, quote, we can't land, a bird got stuck in the engine. Now, the first thing I want to call your attention to is the aircraft made a mayday call at 8.58 a.m.,

and landed at about 9.03 or about five minutes later. Now that is a really short time to run all the emergency checklists and to land. If the crew were in a desperate situation, then sure, they would want to get on the ground as soon as possible. But if, for example, they suffered a single engine failure after apparently ingesting a bird, it may have made more sense to get a delay vector, thoroughly run through all of the relevant checklists,

They had briefed the flight attendants and passengers about the situation. And maybe they were able to accomplish all of that in five minutes. But it would have been very rushed and prone to error because here's what they had to do in that time.

They made an approach to runway one, and it sounds as if the gear was not down for that first approach to the runway. They had to do a go-around, which is a lot more complicated than a go-around in a single-engine piston. I've mentioned at least once before that an airline captain told me that they do so few go-arounds for real, and although they do practice them in the simulator, he said to me that each time they have to do one for real, we usually mess it up. And by that, I think he meant that they forget something or they do something out of order.

And then after the go-around, the crew had to fly a traffic pattern, get themselves turned around 180 degrees, configure the aircraft again for a landing, and then land in the opposite direction on runway 19.

So this crew had to do a remarkable amount of work in just five minutes, while apparently also dealing with an engine failure. And my key point is that unless this were a dire emergency, such as smoke in the cockpit or a dual engine failure, it's possible that the crew might have been more successful if they'd taken a delay vector to give them just a few more minutes to run all the checklists, secure the engine properly, and make sure the aircraft was fully configured for landing.

In general, when you have an emergency in the cockpit, you don't want to rush to deal with the emergency as that increases the chances that you'll do the wrong thing and make it worse. The two adages I've heard is that the first thing you do when you have an emergency is to either wind the clock or to get a cup of coffee. In other words, be deliberate in your approach to dealing with the emergency.

Taking a moment to pause and think about the emergency usually makes more sense than rushing to deal with a situation, as when we rush, we sometimes make mistakes. Probably the biggest unanswered questions are why the aircraft landed with the gear up and the flaps up.

We don't know why they were up, and there are a number of possibilities. Here are some of them. One, it's possible that the landing gear and flap operating systems were sufficiently damaged that the gear and flaps couldn't be lowered. Two, it's possible that the gear and flaps could have been operated, but the crew elected not to lower them. And three, it's possible the gear and flaps could have been operated, but the crew somehow forgot to lower them. Let's take these one at a time.

The Boeing 737 has multiple hydraulic pumps, and most of the hydraulic plumbing is inside the aircraft, where it's unlikely that it could be damaged by a bird strike. In addition to the multiple hydraulic pumps, the gear can also be lowered manually. So given all of this redundancy and the manual gear extension capability, it seems unlikely that the landing gear and flaps were inoperable, though it's certainly possible.

John Astrauer, who writes The Air Current, talked about this accident on X and wrote, quote, When the global air travel system achieves an incredible level of safety through deliberate engineering and organizational safeguards, the remaining accidents are at the edge of the bell curve, ensuring they will be increasingly bizarre. And so it's possible that investigators will find out that there was some new, bizarre, previously unanticipated combination of factors that prevented the gear from being lowered.

Personally, I think it's more likely that the gear was operable and that the crew either chose to leave it up or inadvertently forgot to lower it. Miles O'Brien has commented that he thinks that the explanation that makes the most sense and fits the data is that the crew was facing some type of dire emergency, such as a dual engine failure, and that they purposely left the flaps and gear up.

so as to get the best possible glide from the aircraft. And I agree, that's a plausible scenario. Certainly any time any pilot feels that they may come up short of the runway and that they need to extend their glide, they would put off lowering the flaps and gear until the last possible moment so as to extend the glide. One thing that undermines that theory is that the gear and flaps were not lowered just before touchdown.

The aircraft apparently didn't touch down until nearly halfway down the runway, which suggests that there may have been time, just as they were reaching the threshold, to lower the gear and flaps. Certainly, lowering the gear and flaps would have given them some additional drag, which might have led to an earlier touchdown and more time to brake before reaching the end of the runway.

Another scenario is that, in their haste to land, the crew either didn't have time to lower the gear and flaps, or forgot to lower the gear and flaps. In another interview, the witness who shot the video said, quote, When a plane turns around, small planes such as light planes make a big turn, but this time it turns small, suggesting that the plane made a fairly tight turn from downwind to join the final, which fits with the very short timeline we have from the Mayday call to the landing.

but flying a small, tight pattern would reduce the time available to configure the aircraft for landing and increase the chance of forgetting to lower the landing gear and flaps. And here's a point that GA pilots who fly retractable gear aircraft may want to consider. I've read that the event most likely to proceed to gear up landing is a go-around. In other words, pilots will often have their aircraft properly configured for landing and then for some reason have to go around.

Then they raise the landing gear and fly a traffic pattern back to the runway, but forget to lower the landing gear on the second approach to the airport. Here's one way that can happen.

I used to own a Cessna T210 with a partner, and my practice was that whenever I was inbound on the 45, I would always lower the landing gear at that point. And I did it that way every time so I wouldn't forget. However, if I were ever to do a go-around and raise the landing gear, I would have stayed in the traffic pattern and would not have flown inbound on the 45 again. Hence, I wouldn't have passed the point that was my trigger for lowering the landing gear, and I might forget to lower the landing gear.

So my procedure could have easily led to a gear up landing following a go around. So one recommendation that I've heard and that I like is that if you have to do a go around, don't raise the landing gear, leave it down. That way you won't forget to pull it down when you come back around to attempt a landing a second time. And we did something similar one time in a vision jet for the shortest flight I've ever made in that plane.

We'd been doing training at the Merced Airport , but they didn't have Jet A available at the self-serve pump, so we flew to the Kassel Airport , which when measured from the ends of the two runways is only 4 miles away. Essentially, when you take off from Merced, you're practically lined up for the runway at Kassel. So you could take off, climb perhaps 1,000 feet, and then land straight ahead.

The whole trip takes perhaps two or three minutes. So I told the pilot, after you take off, do not raise the landing gear. Leave it down because it would be easy to forget to lower it on such a short flight. Now let's talk about the speeds I was able to infer from the restaurant owner's video. There is no ADS-B landing data available, so until information is downloaded from the flight data recorder, the video contains the only clues we have as to the aircraft's speed.

Now that video was unlike any I've ever seen. When I first viewed the video, I noticed that the aircraft didn't appear to slow down appreciably after a touchdown. A few days later, I began wondering about the aircraft's speed as it went off the end of the runway.

So I imported the video into my video editing software and began examining it frame by frame. That let me estimate the aircraft's speed at the end of the runway, but then I got curious about the speeds throughout the landing, so I investigated them as well. What I found was surprising, and not what you'd normally expect after a Europe landing.

To figure this out, I looked up the length of a Boeing 737-800, and most sources say it's 129.5 feet long. Then I looked for objects in the video, such as trees, the terminal building, and a tower, where you could clearly see both the nose and the tail as they passed those points. Then I counted the number of video frames between the nose and tail passing each point to determine how many fractions of a second it took.

The video appears to be shot at 23.98 frames per second, so 12 frames would be half a second. Then it's easy to calculate the speed at which a 129 foot long aircraft would have to be moving if, for example, there's a one half second time difference between when the nose and the tail pass the same object. But there is some inaccuracy, probably on the order of plus and minus 10%, in measuring the speed this way. For example,

if it took 10 frames for the airplane to pass an object, if it actually passed the object half a frame early or half a frame late, we could be off by as much as one frame, which would be 10% of the measurement. So what's important about the speed numbers I'll give you is not the absolute numbers, because they could be off by as much as 10%. But by the trend of the speeds as the aircraft moved down the runway. And that trend is what's surprising.

I made the first measurement at the point where the tail touched down on the runway and created a small cloud of smoke. That speed measurement is the least accurate as it's the farthest away from the camera, and the aircraft is a small target and it's not perpendicular to the camera.

It was the only measurement where it could easily have been either 11 or perhaps 12 frames. Adding and subtracting 10% from both of those measurements gives a speed range of 137 knots to 183 knots, with an average speed of 160. So let's say the aircraft first touched down at 160 knots. That, of course, is fast for a 737, but you'd expect it to be faster as the gear and flaps were up.

As the aircraft passed in front of the terminal building, it took 10 frames to pass, which is 183 knots with an error range of 164 to 201 knots. As it passed the tower, it took 11 frames, which is 167 knots, with a range of 150 to 183 knots. As it passed another tower, it was 10 frames for 183 knots,

It then passed a sign in 10 frames, which would be 183 knots, and that was probably the most accurate measurement since the plane was nearly perpendicular to the camera. It then went off the end of the runway, and when it was about a plane length into the grass, it measured 12 frames or 153 knots with an error range of 137 to 168 knots.

So the numbers bounce around a little bit because of the error in this type of measurement. And while experts have commented on the aircraft landing fast, they have missed this point. The aircraft touched down at about 160 knots, and after it went into the grass, it was still doing about 152 knots.

During those almost 14 seconds, it traveled two-thirds of a nautical mile, and yet it was moving at substantially the same speed the entire time it was sliding down the runway on its belly in two engines. But typically after gear-up landing, an aircraft slows down relatively quickly. But this one left the runway at nearly the same speed at which it touched down. And the only way that could happen is if the engines were developing a lot of power and weren't at idle.

I can only think of two reasons why the engines might be at high power as the aircraft slid down the runway. One is that somehow the signals between the thrust levers and the engines were interrupted, and the crew couldn't bring the engines back to idle. Another is if the crew somehow forgot to lower the gear, touched down on the runway, and then decided to try to go around. And if you're thinking, that is crazy, no pilot would ever do that,

Remember that this aircraft touched down about halfway down the runway at high speed, and the pilots could have thought going around would be the best course of action. And believe it or not, if they did, they would not be the first crew to have tried to do that. On May 22, 2020, Pakistan International Airlines Flight 8303 and Airbus A320 was on a domestic flight to Karachi, Pakistan.

During its initial landing attempt, the aircraft touched down without the landing gear deployed, resulting in a belly landing that caused significant damage to both engines. The pilots initiated a go-around, successfully got the airliner back into the air, and traveled a few miles. But then the damaged engines failed, leading to a crash in a residential area near the airport. 97 of the 99 people on board died, along with one person on the ground.

And Air India Express Flight 812, which we talked about in Episode 321, also involved a crew that touched down long and fast in the 737. In that accident, the captain had been sleeping for much longer than the recommended nap period of 30 minutes. Naps longer than about 40 minutes can lead to sleep inertia, which is a period of impaired performance and alertness that occurs during the period immediately after waking up.

The plane arrived high, intercepted a higher false glide slope on the ILS, leading to a high and fast approach to the runway. Now in that accident, the landing gear was down, but after landing long and braking, they decided to go around, but it was too late. They went off the runway at high speed, killing 158 people with just 8 survivors. And by the way, both the Air India flight and the Jeju flight we're talking about were both out-and-back flights flown in the wee hours of the morning.

Jeju flight 2215 left Mawon at 9.04 p.m. the night before and flew five hours and 45 minutes to Bangkok, landing at 2.28 a.m. Korean time.

It was on the ground for about two hours and departed about 50 minutes behind schedule at 4.29 a.m. Korean time and flew about four and a half hours to return to Muon Airport. Now, it's not known if the same crew flew both legs, though it seems unlikely as the hours flown would exceed the limits for pilots in Korea unless there was a second co-pilot, in which case it would have just barely been under the maximum duty hours.

One other thing I want to mention about the crash we're talking about is that toward the end of the video, one can see the thrust reverser is deployed on the number two engine. But it's difficult to tell if the number one engine thrust reverser was also deployed. It's only toward the end of the video that we can see that one of them is deployed, and there's no way to know if it was deployed immediately after touchdown or perhaps much later sometime during the slide down the runway.

So regarding the Jeju accident, I tried to verify another alternate explanation, which is that the aircraft touched down at high speed and did decelerate normally as it was sliding down the runway. But the data just don't support that theory.

As I mentioned, the least accurate speed measurement was the one when the aircraft first touched down. If the aircraft was at the high end of the error range, it touched down at 183 knots. But the last speed I measured when the aircraft was still on the very end of the runway was 183 knots with an error range of 164 to 201 knots. And that measurement should have been the most accurate measurement

it since it was directly opposite the camera location and the closest position to the camera. So even if the aircraft touched down at 183 knots, the data show it was still doing 183 knots at the end of the runway, and the only significant deceleration occurred after the aircraft was in the grass. So I do not know what caused this crash, nor do I claim to know.

But I think the investigation will show that this aircraft landed long. It did not slow down much at all before it went off the runway, possibly because the engines were still operating at a higher power setting. And I hope a key thing that you'll take away from this is that if you ever have a gear up landing, accept your fate and let the airplane coast to a stop on the ground. Attempting to go around after the belly starts sliding down the runway is foolish thinking that could get you killed.

you're far better off letting the aircraft decelerate and possibly hit something at a slow speed than you are getting back into the air and possibly hitting something at a high speed. For the crash we've been talking about, imagine that after touchdown, the crew was able to bring the engines to idle and the aircraft ran off the runway and hit the berm at, say, 50 knots instead of about 150 knots.

150 knots is three times faster than 50 knots, and so the energy involved in the crash at 150 knots is going to be nine times higher than it would be at 50 knots, since energy increases by the square of the velocity. Think of it this way: suppose someone gave you a hard punch in the arm that really hurt. If they could then hit you nine times harder, yeah, bones would break and you'd be in bad shape. So when you're flying, if you have to hit something, you want to do it at the slowest possible speed with the least amount of energy.

And by the way, the NTSB has sent a team of investigators, including people from Boeing, to help with the investigation. And it's likely that we'll have a preliminary report within a month or two that should answer many of the questions about this accident.

And just a reminder that I love hearing from you and I read many of your emails on the show. If you'd like to send me a message, just go out to aviationnewstalk.com, click on contact at the top of the page. That's absolutely the best way to send me a message. And of course, I also want to thank everyone who supports the show in one of the following ways. We love it when you join the club and sign up at aviationnewstalk.com slash support to

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your silence baby sliding upside down you can all