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Why was there a wall near runway at S Korea plane crash airport?

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Re: Why was there a wall near runway at S Korea plane crash airport?

#231

Post by FabHK »

teleforce wrote: post #214
SR2Z wrote: post #199

Earlier quoted context omitted.

Very, very few airport runways are long enough for a plane without brakes to land halfway and be fine. It's simply not possible to build airports in useful places and guarantee three-mile runways.

Apparently runaway excursions is the third cause of major accidents of large commercial transport aircraft [1]. Muan airport runway distance is one the shortest in Korea, less than 3 km and ironically during the incident reportedly there is an ongoing construction to increase the length of the runaway to more than 3 km, but effectively further shorten the runaway to 2.5 km (similar to Yangyang Airport). Strangely Sou…

> new major airports for example Qatar Doha, US Denver and SA Upington has runaway length close to 5 km.

These are by no means average "new major airports".

Denver airport (from 1989) is the west's largest airport (by land area), and at 5000 ft+ elevation (necessitating longer runways).

Upington in the far North-West of South Africa was built in 1968 to accommodate a full Boeing 747 flying to Europe non-stop during the apartheid regime when sanctions meant that overflight or stops in the rest of Africa were not feasible. It has one of the longest runways in the world due to the use case and hot & high environment at 2800 ft (and was intended as an emergency runway for Space Shuttles, if memory serves correctly). It is hardly used anymore with less than 20 aircraft movements a day.

There is no recent trend for longer runways. The issue is extremely well known and well understood, by and large.

Re: Why was there a wall near runway at S Korea plane crash airport?

#232

Post by Xixi »

khuey wrote: post #178
loeg wrote: post #173

Earlier quoted context omitted.

No one is discouraging investigation of the other factors or thinks they aren't significant.

Except they are and they do. The quoted "air safety expert" in the BBC article essentially says the landing was "as good as can be" and that most or all of the people onboard would have survived if the localizer berm wasn't present.

Are you this "air safety expert" is part of the investigation team? Because otherwise, I don't think the actual investigators care about their opinion, or yours, or that of any media (mainstream or not)...

Re: Why was there a wall near runway at S Korea plane crash airport?

#233

Post by usr1106 »

teleforce wrote: post #214
SR2Z wrote: post #199

Earlier quoted context omitted.

Very, very few airport runways are long enough for a plane without brakes to land halfway and be fine. It's simply not possible to build airports in useful places and guarantee three-mile runways.

Apparently runaway excursions is the third cause of major accidents of large commercial transport aircraft [1]. Muan airport runway distance is one the shortest in Korea, less than 3 km and ironically during the incident reportedly there is an ongoing construction to increase the length of the runaway to more than 3 km, but effectively further shorten the runaway to 2.5 km (similar to Yangyang Airport). Strangely Sou…

Denver needs a longer runway because of its altitude. Doha because of the temperatures. It makes no sense to compare their length with locations at more favorable locations.

Re: Why was there a wall near runway at S Korea plane crash airport?

#234

Post by dredmorbius »

dredmorbius wrote: post #197
reso wrote: post #149

The wall is a red herring. The plane landed halfway down the runway at high speed. Something bad is going to happen if you do that at any runway on earth. In SFO you'll end up in the bay or hit the terminal depending on the orientation. In Toronto you'll crash into a highway. Stop looking at the wall and look at the minutes before the crash.

At the moment before encountering the Muan Murder Wall, there were 181 souls alive, healthy, and uninjured aboard Jeju Air Flight 2216. At the moment after encountering the Muan Murder Wall, there were 2 souls alive, one severely injured, and 179 corpses, most mutilated beyond all recognition. Multiple things had clearly gone wrong with the flight, and we're going to have to wait for results of investigations to dete…

And for the details of the Muan Murder Wall itself.

Here's Google Maps view of the area south of Muan airport:

https://www.google.com/maps/@34.9731352,126.3829389,1299m/da...>

From a road directly outside the airport, looking toward the ILS structure, we see that had the wall itself not been there the plane would have struck a cinderblock wall as it continued on. This would have damaged the aircraft, but less so than a solid concrete wall:

https://maps.app.goo.gl/mMGqBC9PX6sEF85B9>

Switching directions we can look to the south along the path the aircraft would likely have followed. The terrain is flat and clear, save for further navigation light structures which would likely have given way readily to the aircraft:

https://maps.app.goo.gl/Retvh9MH48ta5xPS8>

Note a hill in the distance. This could have helped slow the aircraft further, gently:

https://maps.app.goo.gl/m1D3WrMG5QYz6cvE8> (above image zoomed in).

Vegetation is low trees and shrubs, which again could have provided a fairly gentle stopping force against the airframe:

https://maps.app.goo.gl/aCBtY9at1Q1oCZXz6>

Approximately 300m or so from the end of the runway are a few rather unwisely-located pensions and hotels. Those would likely contribute to ground casualties if impacted.

Another few metres past those, mudlands and bay waters, which would be more emenable to a survivable overrun.

Re: Why was there a wall near runway at S Korea plane crash airport?

#235

Post by FabHK »

timewizard wrote: post #226
reso wrote: post #149

The wall is a red herring. The plane landed halfway down the runway at high speed. Something bad is going to happen if you do that at any runway on earth. In SFO you'll end up in the bay or hit the terminal depending on the orientation. In Toronto you'll crash into a highway. Stop looking at the wall and look at the minutes before the crash.

> The wall is a red herring. This is not how safety works. > Something bad is going to happen if you do that at any runway on earth. Then the question is can we do any sort of engineering to reduce the number of fatalities that might occur when this _inevitably_ happens. > Stop looking at the wall and look at the minutes before the crash. The plane hit the wall and exploded. The wall seems pretty important here. I me…

You could mandate that airports incorporate runways shaped as disks with 10 km diameter and another 5 km of empty space around them.

Accidents would still happen.

Re: Why was there a wall near runway at S Korea plane crash airport?

#236

Post by dredmorbius »

yongjik wrote: post #227
dredmorbius wrote: post #204

Earlier quoted context omitted.

I'm going through more of the Wikipedia category entries. AA 1420 (1999) is notable for similarities with Jeju 2216: The aircraft continued past the end of the runway, traveling another 800 feet (240 m; 270 yd), and striking a security fence and an ILS localizer array. The aircraft then collided with a structure built to support the approach lights for Runway 22L, which extended out into the Arkansas River. Such stru…

I looked up the AA 1420 crash report (linked from Wikipedia) and it says: https://www.ntsb.gov/investigations/AccidentReports/Reports/... > The calculated ground trajectory indicated that the flight 1420 airplane departed runway 4R at about 97 knots and impacted the runway 22L approach lighting system support structure at about 83 knots. 97 knots is 112 mph. Somewhere below another commenter said Jeju Air 2216 left t…

1420 airplane departed runway 4R at about 97 knots and impacted the runway 22L approach lighting system support structure at about 83 knots.

That's a more explicit restatement of my own "likely as AA 1420 had decelerated significantly both on the runway ... and its subsequent 240 cross-terrain slide."

Jeju 2216's lack of braking authority may have resulted from a dual engine outage, possibly a consequence of pilot error, noted here:

https://news.ycombinator.com/item?id=42605837>

Absent the ILS structure, the aircraft would have had ~300-500m to decelerate across largely forgiving terrain before possibly encountering fairly light structures, and ultimately bay waters, detailed here:

https://news.ycombinator.com/item?id=42607464>

As I've noted already, we're waiting on investigation conclusions to understand further, though it's entertaining to speculate, and IMO somewhat more productive to look at similar events and history.

Re: Why was there a wall near runway at S Korea plane crash airport?

#237

Post by dredmorbius »

reisse wrote: post #203
teleforce wrote: post #180

Earlier quoted context omitted.

To continue your idiom, it's not a red herring, it's the elephant in the room. Seriously, I think the incident it's a hard lesson for airport designer and ICAO. For better civil aviation safety, the next airport runway should have ample room for safer aircraft landing without landing gears. Previously there's no real-time aircraft tracking requirement for passenger aircraft only for cargo, but after MH370 it's mandat…

No amount of ample room will help if the plane touches down overshooting more than half of the runway. Furthermore (this is pure speculation at the moment) I think chances are the crew were kind of cosplaying PIA PK-8303 - forgot about landing gears in a stress from bird strike, attempted go-around after realising it, but had not enough power from engines due to bird strike or ground hit. It's plausible final investi…

History says otherwise.

Most runway overruns occur with no or few fatalities:

https://news.ycombinator.com/item?id=42606790>

Re: Why was there a wall near runway at S Korea plane crash airport?

#238

Post by dredmorbius »

SR2Z wrote: post #199
teleforce wrote: post #180

Earlier quoted context omitted.

To continue your idiom, it's not a red herring, it's the elephant in the room. Seriously, I think the incident it's a hard lesson for airport designer and ICAO. For better civil aviation safety, the next airport runway should have ample room for safer aircraft landing without landing gears. Previously there's no real-time aircraft tracking requirement for passenger aircraft only for cargo, but after MH370 it's mandat…

Very, very few airport runways are long enough for a plane without brakes to land halfway and be fine. It's simply not possible to build airports in useful places and guarantee three-mile runways.

You don't need the aircraft to survive.

You need the passengers to survive.

And that's eminently possible, even where the hull itself is destroyed (several cases of fuselages splitting in two or three with no or minimal fatalities):

https://news.ycombinator.com/item?id=42606790>

Re: Why was there a wall near runway at S Korea plane crash airport?

#239

Post by Xixi »

reso wrote: post #149

The wall is a red herring. The plane landed halfway down the runway at high speed. Something bad is going to happen if you do that at any runway on earth. In SFO you'll end up in the bay or hit the terminal depending on the orientation. In Toronto you'll crash into a highway. Stop looking at the wall and look at the minutes before the crash.

You are making an assumption here, that I think is unreasonable: that the pilots (who have probably landed at this airport hundreds of times, it's not like they don't know the place) were expecting a large piece of reinforced concrete to be in the path of the plane.

I'm speculating, of course, but pilots made the decision to land there (albeit in a very short amount of time). They probably made the reasonable assumption that they could "safely" (as safe as it can be, of course) overshoot the runway in that direction. They were certainly not expecting to hit a concrete structure that would pulverize their plane.

Having large concrete structures near airports is not unreasonable, hiding them absolutely is. If instead of a hidden piece of concrete it had been a terminal like in SFO, a sea wall, or another known hazardous structure, the pilots could very well have decided to land somewhere else. Including in the very large body of water next to (or beyond) the runway.

You don't know, I don't know, and we might never know depending on what is uncovered by the investigation.

Re: Why was there a wall near runway at S Korea plane crash airport?

#240

Post by neom »

mmooss wrote: post #230
neom wrote: post #158

Earlier quoted context omitted.

It was in gound effect floating till very near the end, these two video show the story very well: https://x.com/vinfly4/status/1873285591900836307 https://www.reddit.com/r/aviation/comments/1hopl7d/longer_vi... As you can see, it actually isn't touching the ground for quite some time, it looks like it because one of the engines is smoking and the plane is throwing up dust etc from the ground as it floats above. Pure…

Assuming that's true, would earlier ground contact have saved lives by slowing the plane more before colliding with the barrier? I don't know if we could expect the pilot to know about or expect the barrier there.

Obviously hard to answer your question but if you're curious, some other bits of info I've gleaned from my autistic research mode. Some context: Bird strike was believed to be on engine 2, hydraulics are powered by engine 1. Few things seem fine as ideas to me - gear down at the speed they were going with the flaps stuck and thrust reversers sketchy, would probably cause under carriage separation, they're apparently trained to do a belly landing if they think this would happen as it's safer. The plane is in a 10/10 perfect config for a belly landing. (note: the config for belly landing and go around and extremely similar) Separately: The manual release requires you to unscrew something that takes about 60 seconds, and then violently swing the plane back and forth, pilot would not want to come off glide slope and even if they did, rocking the plane around at that low low altitude, not good. Separately: apparently in the time they turned, and crashed, there is no way they had time to run checklists, so they where according to the pilots I watched, probably just flying.

If the birds either took out both engines or engine 1 stalled under the load of engine 2 surging and dying (apparently common) - it seems to me they had no good options but to execute that tear drop turn that is apparently VERY MUCH not recommended as it's very very hard (but they did it) and get the plane down asap asap. Provided it's not pilot error and they shut down engine 1 in a panic by mistake (has happened before, fatally) - it seems they could very well have just gotten a very very very very bad, unlikely but possible, series of events. Makes me sad.

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