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I'll recite an avherald comment: If you look at "Video of aircraft after touchdown sliding along the runway and impacting the fence:", you will find out that

I'll recite an avherald comment: If you look at "Video of aircraft after touchdown sliding along the runway and impacting the fence:", you will find out that it took them ~1.7 sec from leaving the tarmac until they hit the construction. If you measure the distance on Google earth you come up with ~140m. That means they hit the construction with roughly 296km/h or 160 knots. If it wasn't the construction it would have been the treeline or something else. That plane was doomed, concrete construction or not.

loeg 2y ago
Maybe. But maybe another 1000m of dirt would have been enough to slow them before the treeline. The area south of the runway is mostly an easement for the ILS approach equipment, then a parking lot and finally some trees. It's also definitely the case that the cement-reinforced dirt mound is not best practice for a locator array.
- TylerE 2y ago
  Yes, but in basically every single circumstance if you have room for 1000m of dirt, you have room for another 1000m of runway, which is even safer.
  - bombcar 2y ago
    This is the reality - most airports run their runways “to the fence” for some variation of “to the fence”. If they could reasonably have a thousand extra feet of runway they’ll add that, as it supports more operations and doesn’t really hurt. Some of them even move around the recommended touchdown point depending on other factors, if the runway is extra long.
mmooss 2y ago
> it took them ~1.7 sec from leaving the tarmac until they hit the construction. If you measure the distance on Google earth you come up with ~140m. That means they hit the construction with roughly 296km/h or 160 knots. (Assuming the math is correct:) That's the average speed over that distance. The plane would have been slowing down the whole time.
- formerly_proven 2y ago
  I'm not a pilot. In the video it looked like the plane was only running on the rear landing gears, I assume with no brakes applied, since that would've caused it to violently pitch down I assume. Only in the last bit did it pitch down and started scraping along the runway. It certainly doesn't look like it was efficiently shedding speed (but looks can be deceiving).
  - krisoft 2y ago
    > In the video it looked like the plane was only running on the rear landing gears, Are we talking about the same crash? In the video I have seen[1] the plane appears to be on its belly dragging on the runway. 1: https://www.youtube.com/watch?v=qJY7oaZpxDU https://www.youtube.com/watch?v=qJY7oaZpxDU
    - formerly_proven 2y ago
      True! I misremembered, in the longer video it's hard to see that the nacelles are dragging on the ground all the way. Still doesn't seem to slow down much.
      - neom 2y ago
        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://x.com/vinfly4/status/1873285591900836307 https://www.reddit.com/r/aviation/comments/1hopl7d/longer_video_of_the_jeju_air_crash_including/ 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 guessing on my part as someone who isn't involved in aviation but spent a good 6 hours looking into this crash: Pilots tried to go around, put the plane in go around config, couldn't, didn't know what to do, and watched the berm come at them. Extremely sad. How both engines failed? We won't know til blackbox I guess, either pilot error or the bird strike was nuts and took out both engines, also some speculation the go around thrust caused a compressor stall. It looks to my uneducated eyes, from the first video, the left engine is not in great shape. Either way, very awful situation.
drdrey 2y ago
just because that aircraft was doomed (maybe?), that doesn't make it a good idea to have the concrete wall there
hu3 2y ago
160 knots? Google tells me: "Modern jets land between 120–150 kt. This depends on weight, weather conditions and several other factors." So even after scratching asphalt for 2/3 of the runway it was still faster than the normal landing speed. My uneducated gut feeling says pilot was trying to abort the landing.
- sio8ohPi 2y ago
  Normally they land with flaps down, which reduces landing speed.
  - 05 2y ago
    I've heard sometimes landing gear is also involved.. We really need a placebo controlled double blind study to learn if landing gear is actually effective of just a cargo cult like parachutes.. [0] https://www.bmj.com/content/363/bmj.k5094 https://www.bmj.com/content/363/bmj.k5094
    - ahoka 2y ago
      Gears also aerobrake.
- loeg 2y ago
  Yes, it was a very fast landing.
- mianos 2y ago
  There were no flaps deployed. Without flaps it's going to be a lot faster than a normal landing.
MoreMoore 2y ago
So you'd rather them have a certain 100% chance of death instead of more leeway and a chance against much less robust trees? Honestly, if I crash land, I think I prefer 150 more meters and a tree as the obstacle over the concrete block. What is going on here and what's with this crazy ass logic?
- deleted 2y ago
  [deleted]
- blueflow 2y ago
  Do you believe the plane would have stayed in one piece if it wasn't for obstacles?
- hypeatei 2y ago
  > What is going on here and what's with this crazy ass logic? Nothing is crazy about it. Many people in this thread (like you) are in a tizzy over a concrete wall for a plane landing with no gear at high speeds. Your argument is basically "having no wall would make me feel better" which has no logic and very obtuse. The ground is also a hard obstacle and this plane would've hit uneven ground shortly after the runway regardless. It's going to disintegrate either way.

loeg 2y ago

Maybe. But maybe another 1000m of dirt would have been enough to slow them before the treeline. The area south of the runway is mostly an easement for the ILS approach equipment, then a parking lot and finally some trees. It's also definitely the case that the cement-reinforced dirt mound is not best practice for a locator array.

TylerE 2y ago
Yes, but in basically every single circumstance if you have room for 1000m of dirt, you have room for another 1000m of runway, which is even safer.
- bombcar 2y ago
  This is the reality - most airports run their runways “to the fence” for some variation of “to the fence”. If they could reasonably have a thousand extra feet of runway they’ll add that, as it supports more operations and doesn’t really hurt. Some of them even move around the recommended touchdown point depending on other factors, if the runway is extra long.

mmooss 2y ago

> it took them ~1.7 sec from leaving the tarmac until they hit the construction. If you measure the distance on Google earth you come up with ~140m. That means they hit the construction with roughly 296km/h or 160 knots. (Assuming the math is correct:) That's the average speed over that distance. The plane would have been slowing down the whole time.

formerly_proven 2y ago
I'm not a pilot. In the video it looked like the plane was only running on the rear landing gears, I assume with no brakes applied, since that would've caused it to violently pitch down I assume. Only in the last bit did it pitch down and started scraping along the runway. It certainly doesn't look like it was efficiently shedding speed (but looks can be deceiving).
- krisoft 2y ago
  > In the video it looked like the plane was only running on the rear landing gears, Are we talking about the same crash? In the video I have seen[1] the plane appears to be on its belly dragging on the runway. 1: https://www.youtube.com/watch?v=qJY7oaZpxDU https://www.youtube.com/watch?v=qJY7oaZpxDU
  - formerly_proven 2y ago
    True! I misremembered, in the longer video it's hard to see that the nacelles are dragging on the ground all the way. Still doesn't seem to slow down much.
    - neom 2y ago
      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://x.com/vinfly4/status/1873285591900836307 https://www.reddit.com/r/aviation/comments/1hopl7d/longer_video_of_the_jeju_air_crash_including/ 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 guessing on my part as someone who isn't involved in aviation but spent a good 6 hours looking into this crash: Pilots tried to go around, put the plane in go around config, couldn't, didn't know what to do, and watched the berm come at them. Extremely sad. How both engines failed? We won't know til blackbox I guess, either pilot error or the bird strike was nuts and took out both engines, also some speculation the go around thrust caused a compressor stall. It looks to my uneducated eyes, from the first video, the left engine is not in great shape. Either way, very awful situation.

drdrey 2y ago

just because that aircraft was doomed (maybe?), that doesn't make it a good idea to have the concrete wall there

hu3 2y ago

160 knots? Google tells me: "Modern jets land between 120–150 kt. This depends on weight, weather conditions and several other factors." So even after scratching asphalt for 2/3 of the runway it was still faster than the normal landing speed. My uneducated gut feeling says pilot was trying to abort the landing.

sio8ohPi 2y ago
Normally they land with flaps down, which reduces landing speed.
- 05 2y ago
  I've heard sometimes landing gear is also involved.. We really need a placebo controlled double blind study to learn if landing gear is actually effective of just a cargo cult like parachutes.. [0] https://www.bmj.com/content/363/bmj.k5094 https://www.bmj.com/content/363/bmj.k5094
  - ahoka 2y ago
    Gears also aerobrake.
loeg 2y ago
Yes, it was a very fast landing.
mianos 2y ago
There were no flaps deployed. Without flaps it's going to be a lot faster than a normal landing.

MoreMoore 2y ago

So you'd rather them have a certain 100% chance of death instead of more leeway and a chance against much less robust trees? Honestly, if I crash land, I think I prefer 150 more meters and a tree as the obstacle over the concrete block. What is going on here and what's with this crazy ass logic?

deleted 2y ago
[deleted]
blueflow 2y ago
Do you believe the plane would have stayed in one piece if it wasn't for obstacles?
hypeatei 2y ago
> What is going on here and what's with this crazy ass logic? Nothing is crazy about it. Many people in this thread (like you) are in a tizzy over a concrete wall for a plane landing with no gear at high speeds. Your argument is basically "having no wall would make me feel better" which has no logic and very obtuse. The ground is also a hard obstacle and this plane would've hit uneven ground shortly after the runway regardless. It's going to disintegrate either way.