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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?

#301

Post by alkonaut »

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.

If it’s possible in any way to keep the next few km after a runway clear, then it should be clear. Ocean is great. Empty fields are great. If you are lucky enough to have empty fields but put a concrete wall there, then that’s almost malicious.

The cause of any fatality in aviation is never a single thing. It’s invariably a chain of events where removing any one thing in the chain would prevent the disaster.

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

#302

Post by mda »

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…

So survival chance of hitting a concrete wall and open field would be same?

I don't think so.

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

#303

Post by crote »

WeylandYutani wrote: post #252
Aeolun wrote: post #111

Earlier quoted context omitted.

I’m worried about the ocean all the time, so it’s weird to think that’s actually the best kind of scenario.

Well depends on the weather conditions. All the successful plane ditches happened when there weren't any waves.

It wouldn't be a ditch anymore. The plane won't be going perfectly straight and level while hitting the water, so there's a pretty good chance one wing/engine would hit the surface first and cause a cartwheel.

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

#304

Post by [deleted] »

dredmorbius wrote: post #215
mmooss wrote: post #89

Earlier quoted context omitted.

> 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.

Physics hack: The average velocity at constant deceleration is halfway between the initial and terminal velocities. So if we know the landing speed (which should come out of the flight data recorder), we'll know the terminal velocity given the average speed (distance/time) which is determinable from the video. No doubt Jeju 2216 was moving hot, but a longer run could have bled off far more speed, and kinetic energy i…

[deleted]

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

#305

Post by ricardobeat »

nialv7 wrote: post #290
ricardobeat wrote: post #289

Earlier quoted context omitted.

If the wheels drop off my car at 100km/h and I lose control and hit a wall, is the wall the cause of the accident? The barrier was 250m away from the end of the runway, the extra 50m if following regulations wouldn’t have changed the outcome. And if the wall wasn’t there, the plane would dive right into a highway anyway. That’s the point.

bad analogy. a better one would be: a wheel fell of an F1 car, car hit perimeter wall, driver dies. should we maybe put a crash barrier in front of the wall?

This airport is basically already complying with the highest possible standard [1]; so in your analogy the crash barrier already exists, the equivalent argument would be for the track to have a 200m run-off area all around.

It's not feasible to plan for every possible freak occurrence, an accident like this is only possible after a long list of other safety procedures have failed (as is often the case for aviation).

[1] https://en.wikipedia.org/wiki/Runway_safety_area

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

#306

Post by PicassoCTs »

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.

Nowhere else on earth is that structure a concrete wall. Its always some rather flimsy metal structure- designed to crumble.

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

#307

Post by blueflow »

dredmorbius wrote: post #237
reisse wrote: post #203

Earlier quoted context omitted.

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 >

Yes, because the speed was lower. Kinetic energy increases with speed squared. Uncontrolled 300 km/h on the ground kills you in any vehicle.

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

#308

Post by LtWorf »

khuey wrote: post #187
snypher wrote: post #135

Earlier quoted context omitted.

150 knots is like 77 meters a second, a 747 can do like 2m/s^2 braking giving 35 seconds to stop, 1500 meters required. Stopping time: t=v/a, t=77/2. Stopping distance: d=v^2/2a, d=77^2/2*2

Now account for the fact that the plane had no brakes since the landing gear were not deployed ...

A hull rolls better than a wheel? Has humanity been doing vehicles wrong this entire time?

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

#309

Post by xmodem »

ricardobeat wrote: post #305
nialv7 wrote: post #290

Earlier quoted context omitted.

bad analogy. a better one would be: a wheel fell of an F1 car, car hit perimeter wall, driver dies. should we maybe put a crash barrier in front of the wall?

This airport is basically already complying with the highest possible standard [1]; so in your analogy the crash barrier already exists, the equivalent argument would be for the track to have a 200m run-off area all around. It's not feasible to plan for every possible freak occurrence, an accident like this is only possible after a long list of other safety procedures have failed (as is often the case for aviation).…

Perhaps the standard is flawed and needs to be updated.

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

#310

Post by mda »

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.

Terrible take, wall is not the red herring, wall is the reason of deaths of almost all souls in the plane. "Something bad is going to happen" usually has very different outcome than hitting a concrete wall.

Aviation accident history definitely disagrees with you.

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