Lots of airports have obstacles not far from the end of the runway. Burbank, Midway, Orange County are a few that come to mind.
Why did they need to land when they did?
Why did they need to land so soon after the mayday call? (only 8 minutes from mayday to crash, as I understand it)
Why couldn't they land on a longer runway?
Why did they land so far down the runway?
What forced them to land in a clean configuration?
As an airline pilot, these are some of the questions I have. The flight data and cockpit voice recorders should be able to answer these questions.
cameronh90 14 days ago [-]
The obstacle obviously didn't cause the crash, but it's still probable that fewer people would have died if it wasn't there, and it seems to have been put there for no valid reason, quite recently, and against standard practice. Along with the reports that their bird control devices had not been implemented and that only 1 of the required 4 staff to repel birds were on duty. All these factors together may suggest an issue with their safety culture.
Though, I am a little sceptical of the claims that it would have hugely reduced fatalities either way. Runway excursions into unmanaged terrain at that speed don't usually work out well for the passengers, even when the terrain appears relatively flat.
I'm not an airline pilot, but I'm still curious to see what caused such an unusual crash, since there doesn't seem to be any single issue that could have caused what happened. So far, my best uninformed guess is a combination of pilot error and bad luck: the approach wasn't stabilised, so they started executing a go-around, and THEN a multiple bird strike caused catastrophic damage to the right engine. This may have led to smoke in the cabin/cockpit which they interpreted as a fire (or some other issue, vibrations etc.) that made them decide to shut down the engine, but they shut down the wrong (left) engine. So now they think they have a dual engine failure. At this stage they obviously don't have time to run through paper procedures, and they put the plane into clean configuration to maximise glide and attempt a 180 to try and land back on the runway. Then they either couldn't or forgot to deploy the gear, and floated down the runway partly due to ground effect from being at an unusually high speed, thus landing at high speed almost halfway down the runway. Thoughts?
tolciho 14 days ago [-]
"Normal Accidents" is a term for when things, well, normally go sideways in complex systems, and there's a whole book on it. Otherwise, it's pretty typical in disasters for there to be a laundry list of root causes and contributing factors: the Titanic was going too fast, there was hubris, and icebergs, and it was sad when the great boat went down. Could the disaster have been missed or been less bad if one or several factors had rolled up some other result? Maybe! That's what a full investigation is for, to suss out what went wrong and what things are most fixable.
I don't know why the pilots landed the way they did but the structure was there for a valid reason. It's the runway localizer antenna. It was elevated off the ground to protect it from flooding. Should it have been frangible, yes, but it's not at all out of the ordinary as far as structures near runways go, and I think the focus on it is sensationalist and misguided.
cameronh90 12 days ago [-]
By structure I meant the dirt mound with a concrete wall inside it, not the localizer. Entirely normal to have a localizer, but usually on a frangible structure if it needs to be elevated.
jmward01 14 days ago [-]
These were my thoughts exactly. Even if they lost all engines/power/hydraulics they would have had 8 mins to start up the APU so gear and flaps wouldn't have been an issue and clearly they still had some control. Did they try to go around and lose all power on the go? Gear up landings do happen in GA but I can't think of the last commercial aviation gear up landing. There will probably be a lot of useful things coming out of this. Changing design and placement of structures at the end of runways probably isn't a big one though.
pfannkuchen 14 days ago [-]
Were those obstacles installed by the airport though? I thought it was like stuff on land outside of the airport for those other examples.
dmurray 14 days ago [-]
Does it matter? Either it's safe to have obstacles within 300m of the end of the runway, and this was a reasonable location for the Korean airport to put their localizer in, or it's not, and the likes of Burbank should shorten their runway to ensure there's sufficient buffer space at the end of it.
brookst 14 days ago [-]
I’m suspicious of decontextualization in the name of forming “either X or Y” absolutes.
Either 8 character passwords are fine and secure, or bad and should be banned? With no context between “€x8;,O{w” and “password”?
I suspect runway design has more variables than just distance to obstacles.
hmcq6 14 days ago [-]
>and the likes of Burbank should shorten their runway to ensure there's sufficient buffer space at the end of it.
... you can't be serious with this? 300 more feet of unused runway is equivalent to if not better than 300 feet of buffer. You're fixated on following the "rules" without any understanding as to why they exist.
dmurray 14 days ago [-]
Yes, I'm being a bit facetious. I agree with you: there shouldn't be a hard rule of "no obstacles within 300m of the runway, and the Muan airport authorities were negligent in having one".
If they'd shortened the "runway" by 300m (let's say the unused space was still tarmacked and empty, but not designated as a runway, although I understand there are better materials for arresting overruns) would all those people still have died and would people still be blaming the airport layout?
Perhaps the pilot would have made a different decision if the runway was advertised as 2500m instead of 2800m, but that also suggests people are looking at the wrong thing, and pilots looking for emergency landings should consider not only the runway length but also any buffer available.
iso8859-1 14 days ago [-]
The localizer antenna mount (the concrete) was inside the airport perimeter. See diagram:
What they were saying is that just because other airports feature runways situated next to natural obstacles and this is allowed and equally dangerous, it doesn't mean this airport needed to have this particular, deliberately designed and implemented obstacle next to the runway.
The reason for the concrete-reinforced berm was typhoon resilience. It begs the question whether there are alternative designs that are trade of requirements better.
unyttigfjelltol 14 days ago [-]
And if an accident occurred because a typhoon washed out the antenna, people would argue a concrete foundation would have been safer.
As an aside, this reminds of the consideration highway bureaus in the US give to trees and poles.[1] Trees are removed and poles should break easily and fall after a vehicle impact. This comes to mind because I have given most thought to these considerations as a pedestrian, regretting tree removals and feeling exposed to passing cars in a system designed to accommodate them safely (for them) departing the roadway anywhere, anytime. Of course, sometimes broken poles fall on cars or people, power outages are more routine especially after vehicular accidents, and there are other tradeoffs too, some of which are safety-related.
Nice questions. But it doesn't give them right to build a concrete obstacle for lights, when it is possible to make it without hard obstacle.
aaron695 14 days ago [-]
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blueflow 14 days ago [-]
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.
mmooss 14 days 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.
dredmorbius 14 days ago [-]
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 is based on velocity squared, so every bit helps a lot.
SoftTalker 14 days ago [-]
The plane was sliding on its belly, wheels up. It wasn't slowing down very much. Ever play on a slip-n-slide as a kid?
YeGoblynQueenne 13 days ago [-]
Can't speak about the OP but I didn't weigh a few thousand metric tons as a kid.
Or as an adult. I am on a diet though.
dredmorbius 13 days ago [-]
Set yourself a goal!
And good news! A fully-loaded 737-800 has a maximum takeoff weight of less than 80 tonnes, not thousands, so your challenge is much more attainable!
It might not have been slowing down much in that time due to a thing called Ground Effect. Since the wheels weren't down, the flat body of the bottom of the aircraft + wings would have actually reduced drag and cushioned the plane for a bit, causing it to not slow down as much as you would assume.
formerly_proven 14 days 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 14 days 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.
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.
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.
WalterBright 14 days ago [-]
The reason he touched down halfway down the runway could have been because the gear was up. If the gear was down, he would have touched down much earlier. He may not have known the gear was up, or did not account for the gear being up in his approach.
neom 14 days ago [-]
They executed a pretty difficult turn, apparently it's called the impossible tear drop and you're trained specifically NOT to ever do it. I looked at the flight tracking, I suspect the maneuver they pulled just put them at that point in the runway[1]. If you read my reply to the comment above you, it has some additional context you might find interesting. They pilots I watched all mentioned really, it doesn't make sense they cut off the approach, they should have taken the bird strike and continued the landing. The probable reasons given was: took evasive maneuvers to avoid the brids so came off glide slope, not enough engine power for a full go around, then started to get way behind the plane.
Minor nit, I believe it’s called the teardrop go around for such cases. You also have the impossible turn which is meant typically for engine/power failure during takeoff, and it actually is possible to be safely done - as demonstrated by the former ALPA Air Safety Institute Senior VP Richard McSpadden in one of his YouTube videos.
However, it can be deceptively difficult to have the right conditions to pull it off - as demonstrated by the ironically fatal crash that killed Commander (Ret) McSpadden (though iirc it was not clear if he was flying the craft at the time).
(Edits made for clarity/content.)
neom 13 days ago [-]
Thank you for the clarification, I hoped I couched everything enough people knew I'm just reading internet and not at all an expert, I appreciate the reply!
mmooss 14 days ago [-]
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.
neom 14 days ago [-]
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.
dgfitz 14 days ago [-]
I have been under the distinct impression for a long time that a plane slowing on the runway has very little to do with landing gear brakes.
irjustin 14 days ago [-]
That's under normal operation. All planes are certified to stop without any air reverse thrust[0] given they land at the right sized runway, right conditions, right position, etc etc.
But it's definitely part of the program.
They must also sit on the tarmac post heavy braking and the brakes must not burst into flames.
True, though I don't have a breakdown of net effects.
Commercial jet aircraft utilise thrust reversers, speed (or air) brakes (usually control surfaces which can extend out from the aircraft fuselage or wings), and landing gear brakes.
The latter are not insignificant, but thrust reversers and speed brakes are major contributors, especially immediately after touchdown.
There's also the effect of spoilers which increase the load over the gear and hence the braking capabilities of landing gear brakes.
Jeju 2216 failed to utilise nearly all of these mechanisms. It landed without flaps, spoilers, or gear, and possibly w/o thrust reversers.
3ple_alpha 13 days ago [-]
If one divides weight of the airplane by the number of wheels it has, one would find one wheel carries around 10 times more weight than that of a truck. You even get a slightly better deal on landing when you don't have as much fuel.
That's a lot of weight but nothing crazy, so on a dry runway wheel brakes alone are more than enough to stop normally. They would also wear out a lot, overheat and occasionally ignite if used like that, so that's what thrust reversers are for.
mmooss 13 days ago [-]
That mass has much more velocity than a truck.
loeg 14 days 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 14 days 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 14 days 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.
MoreMoore 14 days 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?
blueflow 13 days ago [-]
Do you believe the plane would have stayed in one piece if it wasn't for obstacles?
hypeatei 13 days 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.
13 days ago [-]
hu3 14 days 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 14 days ago [-]
Normally they land with flaps down, which reduces landing speed.
05 14 days 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
ahoka 14 days ago [-]
Gears also aerobrake.
mianos 14 days ago [-]
There were no flaps deployed. Without flaps it's going to be a lot faster than a normal landing.
loeg 14 days ago [-]
Yes, it was a very fast landing.
drdrey 14 days ago [-]
just because that aircraft was doomed (maybe?), that doesn't make it a good idea to have the concrete wall there
neom 14 days ago [-]
My wife is South Korean (from andong). I asked her and she looked at me like I'd grown a second head "because it's South Korea? We're a young country and that is tiny airport in the south, half of Korea is a safety hazard and you know that fine well, some freaking idiot put a wall there, oh well, it's korea" and walked off pretty angry I'd even asked.
bombcar 14 days ago [-]
To be fair to her, check out some of the other things that have happened.
Compared to that mall collapse, a berm that far off the end of the runway won’t even be notable.
neom 14 days ago [-]
Oh I'm fully aware, I take no issue with her ire, just didn't expect that answer, tho I should have. To her point, the South of South Korea, especially in the country area, has loads of stuff like this, there are disasters waiting to happen everywhere, much of the infrastructure should be gone through with a fine tooth comb really, like this still both boggles my mind and boils my blood: https://www.reuters.com/world/asia-pacific/fire-south-korean...
They used a HIGHLY flammable material to completely cover a raised highway.
(All of that said, I read from so many people now that the plane would have disintegrated once it did finally start to drag given the speed, and there is another parameter wall shortly after the berm.)
boodleboodle 14 days ago [-]
Safety hazards and disregard for accesibility as well
14 days ago [-]
carabiner 14 days ago [-]
[flagged]
dang 13 days ago [-]
Personal attacks will get you banned here—and this was a shameful one. No more of this, please.
Edit: we've had to ask you many times to stop breaking the site guidelines:
Eventually we have to ban accounts that keep doing this, so please stop.
14 days ago [-]
fontrash 14 days ago [-]
What the hell.
iso8859-1 14 days ago [-]
[flagged]
neom 14 days ago [-]
"One strategy I use for my relationships with foreigners is to gently pat them on their heads if they understand me. That way, there is positive reinforcement and they are encouraged to improve their understanding." - this may very well be one of the most condescending and disrespectful things I've read on hackernews ever. Also, my wife has a PhD in American History from Yale and teaches at SUNY, I don't suspect she misunderstood the question.
iso8859-1 13 days ago [-]
You're assessment is correct and it was indecent of me to say such things. I'd like to apologize for both the condescension and the lack of respect.
neom 13 days ago [-]
We'll consider the matter settled then. I genuinely appreciate the apologies. Have a happy new year.
shutupnerd0000 14 days ago [-]
[flagged]
dralley 14 days ago [-]
>Tell her she is wrong. It's an international airport with commercial traffic. 11th most busiest airport in the country.[0]
11th out of 15 total, servicing about 4 flights / 630 passengers per day on average using the very same statistics you've linked. That sounds like a pretty small airport to me, both in absolute and relative terms.
"International airport" means very little outside of large nations like the US, Russia, Canada, Brazil or China. Most nations are small enough that there's at least as many foreign airports within a few hundred kilometers as there are domestic ones, and therefore every airport may as well be an international airport.
mikestew 14 days ago [-]
"International airport" means very little outside of large nations like the US, Russia, Canada, Brazil or China.
In the U. S., at least, "international" just means there's a customs station. There are some pretty small airports that have "international" in the name. Fairbanks, Alaska, comes to mind.
khuey 14 days ago [-]
Or Burlington, VT, which doesn't even have scheduled international service.
iso8859-1 14 days ago [-]
That's a great observation about 'international airport'. There is no point in mincing words regarding the definition of 'tiny'. I think you've correctly characterized the size of the airport.
frosting1337 14 days ago [-]
> Tell her she is wrong. It's an international airport with commercial traffic. 11th most busiest airport in the country.
It's... a tiny airport, both by commercial standards and by South Korean standards.
Pretty sure you're just trolling though, no way this is a serious comment.
mcflubbins 20 days ago [-]
I was wondering the same thing and suspected it was some safety feature (better for a plane to smack into said wall instead of crash into some populated area, etc) I had no idea he had to make the approach in the opposite direction.
gazchop 16 days ago [-]
They already botched a gear down landing, which is almost never mentioned. They retracted the gear and did a teardrop go around from a headwind into a tailwind belly flop.
Stinks of bad crew resource management and ATC which is why the ATC and airline for raided by SK officials.
K0balt 16 days ago [-]
We don’t know why the pilot elected to double back instead of go around. There may have been indications of a progressive failure that indicated that course of action, but it does seem hasty. That haste may have caused them to not be able to set up a stabilized, minimum speed approach, and may have contributed to the long touchdown, which certainly was a contributing factor.
If there were significant winds it would have compounded those factors.
It is curious that the gear was retracted. I can only think that this was due to some kind of system failure? Perhaps that same failure explains the decision to double back instead of going around?
Lots of questions, hopefully there will be answers.
Still, the structure does not seem to meet the standard for frangibility that is indicated for objects in the approach path within 300m, although it’s not like it was at the very end of the runway.
Runway over/undershoots are actually quite common, and the building of a nonfrangible structure on an otherwise safe skid zone is a significant error in design principles that is not common or conformal to industry standards.
If those antennas had been placed on property designed towers instead of a concrete bunker, the passengers and crew very well may have walked away without a scratch, despite any errors on the part of the crew or procedures of the airline.
loeg 14 days ago [-]
They declared mayday and then were on the ground in like 3 minutes. I think they probably just forgot gear given how rushed the landing was. We'll find out from the investigation.
earnestinger 14 days ago [-]
Youtuber’s Denys Davydov (ex pilot of same plane), pet theory: bird got into the engine, pilot by mistake shut off wrong engine, due to no engine - hydraulic pump was non-functional, which resulted in landing gear problems. (also something about ground effect)
dredmorbius 14 days ago [-]
This wouldn't be the first time a pilot killed the wrong engine:
"TransAsia Pilot Shut Off Wrong Engine Moments Before Crash" (2015)
Taiwan aviation officials on Tuesday released a detailed report of how the pilot mistakenly shut off the plane's only working engine after the other lost power. "Wow, pulled back the wrong side throttle," the captain said shortly before crashing.
I seem to recall a Mentour Pilot episode (YouTube channel) describing either that or a similar incident.
Point being that when things start going very wrong you've got to actively think to prevent making them worse.
sitkack 14 days ago [-]
This whole thread is a tire fire poor logic and critical thinking.
That said, I have seen some absolutely horrendous responses to emergencies go from kinda bad to massive destruction of property, so much so that unless one has trained for the specific emergency, the best course of action is to assess way more than you think you need. And we often have more time than we think, and we make the the right decisions, they are the right decisions because they give us more time.
loeg 14 days ago [-]
So... the degree of control they have over the plane on landing suggests they have some degree of hydraulic control. It's possible they throttled down the wrong engine, but this is speculation at this time.
Landing gear has a manual gravity release by the first officer that doesn't require the hydraulics. (But does take some time.)
Ground effect was certainly involved (why they glided so far before touching down) but the bigger factor was their high speed, lack of flaps, and lack of gear.
markdown 14 days ago [-]
> Landing gear has a manual gravity release by the first officer that doesn't require the hydraulics. (But does take some time.)
You have to reach all the way back to do it, difficult to do with all the other shit going on.
loeg 14 days ago [-]
Yes.
gazchop 16 days ago [-]
They retracted the gear after the first landing attempt. I suspect they either missed it on the teardrop or had secondary hydraulic failure and no time to do a gravity drop. I would err on the side of crew error because there were clear signs the hydraulic systems were functioning (thrust reverser and that they could retract the gear in the first place). Hydraulics don’t fail instantly and one engine was spooling still on landing.
That's why EASA says put the plane down if there’s a strike on approach. Ryanair 4102 is a good example of a close one there as a reference.
loeg 14 days ago [-]
I've seen reports they had gear down in the first approach and also that they didn't. Is there anything conclusive yet?
xigency 13 days ago [-]
Yes, if you view the footage of the bird strike on first approach you will see the landing gear is extended.
ETA: The primary footage is hard to find now that the topic is so saturated, but there is a specific clip from a close vantage where it is highly visible. I'll include a link if I can find it.
People often have an idea that ATC actually controls what happens. They just give advisory guidance to pilots, who ultimately decide what to do. A clearance to land or the lack of one does not absolve the pilots from making their own judgments and decisions about how to conduct the navigation of the aircraft, and where and when to land.
Usually, it’s a bad idea to not follow ATC guidance, but in the case of emergencies especially, pilots call the shots.
ptsneves 14 days ago [-]
Don’t know why you are downvoted. I was even taught that if after reporting an emergency you are overwhelmed by information requests you should just mute the radio and focus on solving the emergency . ATCs job is to get everybody out of the way including themselves.
bombcar 14 days ago [-]
ATC can cause crashes by vectoring planes at the same altitude.
But the tower at an airport, their job is to supply information, and once you call mayday you’re in total control - you can ask them to do whatever you think will help you save the flight, including (and usually automatically done) diverting all other flights, clearing all runways, and cancelling any departures pending until the issue is resolved.
Pilots have to be trained to ignore ATC as necessary, because planes have crashed because of trying to be polite to requests (and not declaring mayday or pan pan).
Yeah, especially given the mayday call, ATC is trying to give pilots the information they need, prepare emergency services, and get the fuck out of the way.
gazchop 16 days ago [-]
Possible comms failure. ATC are responsible for reporting surface wind. It may have lead to a bad decision by the pilots. Go around versus teardrop etc.
whycome 14 days ago [-]
Botched how?
mianos 14 days ago [-]
Botched by not using the manual gravity gear drop. Maybe they didn't have enough time. But losing a single engine is not necessarily fatal at that flight phase. Most professionals are still questioning why the rush to get it down. If there is some valid reason, aside from accidentally shutting down the other engine, when we do find out the details, maybe the professionals won't call it botched.
whycome 12 days ago [-]
Can’t really call it botched until we know the reason…
aaron695 16 days ago [-]
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Towaway69 16 days ago [-]
This:
> no idea he had to make the approach in the opposite direction.
So the wall is actually at the beginning of the runway. That wall was never never meant to be at the end of a landing but at the start of landing.
I don't understand why this isn't made clear. Basically the runway was used against the design specifications.
ra 16 days ago [-]
That's not correct. A runway can be used in either direction, if you look on Google maps you can see the runway at Jeju has markings at both ends including a number (denoting it's compass heading) - both ends are usable.
You always want to land with a headwind and never a tailwind, so ATC will use whichever end is favorable for the current conditions.
In this case, if they attempted to land with a tailwind then the on-heading vector component of wind velocity must be added to the airspeed to get the ground speed... whilst this was a contributing factor to the accident, it's not something to focus on.
There will be a thorough investigation but it will take some time to get answers.
rich_sasha 16 days ago [-]
I read that the opposite direction had a NOTAM exclusion, i.e. was excluded from use. From the professional pilot forum linked a few days ago in a similar thread.
If that's right then OP would be correct in saying, this direction wasn't meant to be used.
bombcar 14 days ago [-]
Depends on why it was NOTAM’d - could be that the localizer was out, that there was a noise abatement, or other reasons.
Part of preflight is investigating those so you know what are options at what are not - entirely closed runways will be indicated if they’re actually broken up or just marked closed.
loeg 14 days ago [-]
Ok but in an emergency all bets are off, the opposite direction is better than a crash landing. So you can't just assume 100% of landings are in one direction.
lmm 14 days ago [-]
> Ok but in an emergency all bets are off, the opposite direction is better than a crash landing.
Sure, but so is a highway, or a river. Doesn't mean those should be built to runway standards.
loeg 14 days ago [-]
Ok but this is a runway. It should be built to runway standards!
It's a runway in one direction only. It doesn't need to be built to the standards for a runway operating in the opposite direction, because it isn't.
Towaway69 16 days ago [-]
Thanks for the clarification :+1:
It should perhaps be pointed in news coverage since I equated "opposite direction" with "wrong direction" - hence my scepticisms about the wall.
kgwgk 14 days ago [-]
> if you look on Google maps you can see the runway at Jeju
Do you mean at Muan?
K0balt 16 days ago [-]
Idk about this particular airport but it is nearly universal that runways are used from both ends. The idea is to land into the wind.
We don’t know why the pilot elected to double back instead of go around. There may have been indications of a progressive failure that indicated that course of action, but it does seem hasty. That haste may have caused them to not be able to set up a stabilized, minimum speed approach, and may have contributed to the long touchdown, which certainly was a contributing factor.
Still, a 14 ft high concrete structure within 300M of a runway end is unusual, and does not fit the standard for frangable structures which is the guidance for runway aligned equipment.
14 days ago [-]
weweersdfsd 16 days ago [-]
Even if the runway was only used from one direction (not true), it would be dumb to build a big concrete structure near its beginning. It's not unheard of for planes to come in too low and touch down before start of the runway due to pilot error (or even double engine failure on rare occasions).
ajmurmann 16 days ago [-]
Was the runway designed to only be used one way or was this just the it opposite direction of how it was being used at that moment? I understand that at least some airports change the direction based on wind.
notimetorelax 16 days ago [-]
Runways are approached from both ends depending on the wind.
dredmorbius 16 days ago [-]
This depends strongly on the airport, terrain, and variability of winds.
There are airports in which approaches always or very nearly always follow the same profiles given local conditions. SFO, SJC, and SAN would be three examples off the top of my head.
SFO's major approaches are over the bay, opposite approaches would involve rapid descents dictated by mountains near the airport.
SJO and SAN are both limited by proximate downtowns with tall towers. Nominal approach glide paths cut below the rooflines of several structures, and make for some interesting experiences for arriving travellers.
Are we expected to believe these pages never got crawled before?
Can we learn a forensic lesson for this and automatically snapshot similar pages for all runways worldwide?
loeg 14 days ago [-]
FYI, the 01 and 19 names are short for 10 and 190 degrees -- so it's always going to be the case that the opposite runway direction is 18 mod 36 from the other direction.
sio8ohPi 14 days ago [-]
I don't see that note. There's one "extreme caution" note but it's about some other obstacle 2.1NM from the threshold of runway 1.
DoctorOetker 14 days ago [-]
> 1.3 Pilot shall use extreme caution during carrying out final approach into RWY 01 or missed approach or departure for RWY 19 due to obstacle located east of extended RWY at approximately 2.1 NM from threshold of RWY 01.
Almost anything that is 500m causes an obstacle notice to exist. There are tons of them and most mean nothing unless you’re flying an overweight small plane in the dark desert heat.
lutusp 16 days ago [-]
> So the wall is actually at the beginning of the runway. That wall was never never meant to be at the end of a landing but at the start of landing.
Airports like this are designed to have two approach directions -- in this case, 10 and 190 degrees. Either approach direction would have been acceptable depending on the prevailing wind.
16 days ago [-]
16 days ago [-]
16 days ago [-]
psychoslave 16 days ago [-]
Just a message thinking for anyone reading who might have had some relative in this plane: sincere condolences.
14 days ago [-]
Yeul 16 days ago [-]
I have been to airports whose runway end in the ocean, a swamp, a mountain and a 5 lane highway.
Aeolun 14 days ago [-]
I’m worried about the ocean all the time, so it’s weird to think that’s actually the best kind of scenario.
WeylandYutani 14 days ago [-]
Well depends on the weather conditions. All the successful plane ditches happened when there weren't any waves.
crote 13 days ago [-]
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.
dominicrose 16 days ago [-]
A plane usually crashes because of multiple reasons. The fact that runway design was one of them is a big deal because it was a concern for all airplanes landing there not just one of them.
Ate Chuet made a quick analysis about the crash: https://youtu.be/xUllPqirRTI. The wall is there because that area is regularly flooded, it serves for the ILS system, and it is unfortunately over the minimum legal distance for such an object.
harshreality 14 days ago [-]
It doesn't make sense, though, that it would have to be concrete-reinforced above ground, and non-frangible, just because the area floods.
Maybe it's the cheapest way to engineer the ILS localizer to be flood-resistant? I don't know.
Waterluvian 14 days ago [-]
Feels like a “pieces of flair” issue.
The runway should be as long as it’s required to be. If after (and before) the paved runway they need a length of open space, that should be however long it is required to be, too. Beyond that there could be a minefield, a pillow warehouse, an ocean, a mountain, etc. It shouldn’t matter.
bombcar 14 days ago [-]
After the arrestorbed will be a massive magnetic sled that will accelerate to the speed of the plane and then decelerate the whole thing!
Only infinity billions of dollars for each airport and likely cause other issues, but, progress!
baq 16 days ago [-]
The title question is like the 20th in order of importance why this crash happened…
16 days ago [-]
blitzar 14 days ago [-]
Cause of death was impacting a concrete barrier.
ynniv 14 days ago [-]
Cause of death was landing halfway down a runway at high speed with no gear. Why were they cleared to land if they hadn't set flaps and locked gear? There was ocean in front of them both before and after their turn: landing there would have been more survivable than landing fast and hard with no gear. They were below minimum turnback altitude, and wouldn't have been able to complete the planned turn without the same power that could have been used to stay aloft and sort out their problems.
Nothing about this crash was normal, and talking about a thing past the end of the runway is misdirection.
bink 14 days ago [-]
They declared an emergency. It's typical in that scenario to be approved for whatever runway the pilot deems best... or golf course... or field.
russdill 14 days ago [-]
Engine losses due to bird strike are pretty common. Planes declare an emergency and are vectored to a holding pattern where they run though emergency checklists and verify that they are ok to land at the current airport with current capabilities, weight, weather, etc. This takes 10 to 20 minutes.
This did not happen on this flight
ynniv 14 days ago [-]
According to the timeline I saw they were cleared before declaring an emergency. This means at the time of emergency the standard checklist required their gear had been locked and flaps set. Either they were not operating within regulation before they declared emergency, or they raised gear and retracted flaps below 900 AGL and decided to make an impossible turn instead of stabilizing their flight.
I don't know what happened in this event, but the concrete box is painfully uninteresting compared to basically anything that happened before it.
bombcar 14 days ago [-]
They had gear down, got a bird strike, did a go around, and retracted gear. At that point everything is fine and by the book but what happened next is the question - and why.
ynniv 14 days ago [-]
Either they would have actually "gone around" and executed the original approach (which would have been aborted when the gear didn't lock), or they had had mechanical problems and wouldn't have been able to make this 180º turn if they wanted to. There was ocean on three sides of them that would have provided a rough but survivable landing, as demonstrated a decade ago in New York.
At no point was this landing fine or by the book, and talking about ground obstructions is just a way to distract you.
blitzar 14 days ago [-]
If we go back far enough the fatal error is the Wright brothers inventing the airplane.
It might be more useful to start with the solid concrete plane stopper and work backwards than work forwards from 1903.
ge96 16 days ago [-]
I was wondering what if they tried to turn whether by rudder or thrust differential would the outcome have been different/worse. Maybe you can't do much at that speed and so little room.
lutusp 16 days ago [-]
I'm a pilot. The airplane was sliding on the ground and the landing gear was not deployed. Too fast to stop but not fast enough to use the rudder for directional control. There was no realistic chance to change direction.
If there had been enough engine power to control direction on the ground, there might also have been enough power to remain airborne, but based on limited information, that wasn't so. Under the circumstances the pilots would have wanted to stay airborne to buy time for a more controlled descent, were that possible.
All these speculations are preliminary and may completely change once the black box information is released.
rogerrogerr 14 days ago [-]
> not fast enough to use the rudder for directional control.
Sure about that? 160kt (how fast someone calculated it went off the end of the runway) is way above Vs1 for a 737, there should be plenty of rudder authority. Heck, Vapp is usually in the 130-150kt range.
bombcar 14 days ago [-]
Rudder authority in the air, but scraping on the ground you’re not going to change direction - or take-off, either.
If they were trying to take off again, there wasn’t any hope.
Mistletoe 17 days ago [-]
I don’t know why people keep fixating on this. Airplanes can’t skid out of the airport into the surrounding city. Mistakes were made, but this isn’t one of them. I suspect it is people trying to deflect blame from pilot error, which seems by far the most likely issue. They did none of the things you should do to stop a plane.
csomar 16 days ago [-]
There is nothing beyond the embankment. Airports are generally made in the middle of nowhere. And no, they are not "skidding" into the surrounding city, he probably needed a few hundred meters at most.
Mistletoe 16 days ago [-]
He’s going extremely fast, a few hundred meters would do nothing. I think the estimates I saw were over 150 knots. That’s about 77 meters per second.
I found this comment helpful from a Reddit thread.
>The embankment is there to protect the road from the jetblast of departing aircraft in oposite runway direction. Thats why it is allowed directly in the safety area.
foxglacier 14 days ago [-]
> a few hundred meters would do nothing. I think the estimates I saw were over 150 knots
Show you working. Not feelings because people don't have intuition for such unusual motion. You could equally have said "a few hundred meters would be enough."
snypher 14 days ago [-]
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.
Thanks for the link. Nowhere it seems to indicate that the friction of the breaking would be greater than the friction of the hull, since the pages related to non-destructive braking.
lolc 12 days ago [-]
Airplanes use disc brakes. These can provide pretty much unlimited friction and are very destructive to the brake pads. They are effectively limited by the static friction of the tire and how much waste heat they can dissipate without blowing the tire.
Look it feels like you want to win an argument. You can only win it for people who do not understand the difference between static friction of a tire on tarmac and kinetic friction of a hull on tarmac. I couldn't tell you off-hand which has more friction, but I'm ready to believe by example that the hull has bad properties when it comes to braking. It's made for low friction after all.
loeg 14 days ago [-]
(That's with brakes and flaps.)
psychoslave 16 days ago [-]
Maybe not all completely aligned straight forward with the landing, but it looks like yes there are some inhabited zones over there surrounded by wooded parcels, well before the landscape change for some sea.
Like doing what things? What I read so far is that they suspect the pilot had control issues.
I don't think people who say that it's a bad idea to have a concrete wall at the end of the runway argue the plane should make its way to a nearby motorway. I think most refer to using EMAS, ie a crushable concrete floor in which the plane sinks and stops.
khuey 14 days ago [-]
EMAS is designed to crush under the pressure of all of the aircraft's weight pushing down on the relatively narrow contact area of the tires. There were no tires in this case. I am unaware of an EMAS that has been designed or tested for the far more broadly distributed weight of a belly landing.
cm2187 13 days ago [-]
That’s a fair objection. Still you would expect the plane to sink into the grass after that.
Towaway69 16 days ago [-]
> bad idea to have a concrete wall at the end of the runway
but was it the end of the runway? As I understand, the pilot came in from the opposite direction, i.e.
> The pilot then aborted the original landing and requested permission to land from the opposite direction.[1]
So that wall was located at the beginning of the runway if the runway was used correctly.
From the bottom image[2], it would appear the wall is located behind the point where planes begin their take-off (and I assume their landing) - but I'm no aviation expert.
> So that wall was located at the beginning of the runway if the runway was used correctly.
Most runways are intended to be used in both directions depending on the wind. This one doesn't seem to be an exception?
Towaway69 16 days ago [-]
Yep mea culpa, I now understand a little more about aviation!
16 days ago [-]
HPsquared 16 days ago [-]
Looking at the map, there isn't much beyond the runway.
looseyesterday 16 days ago [-]
You are probably right on pilot error, dont forget Boeing probably want this to be the story as well!
iso8859-1 14 days ago [-]
The 737 is one of the most popular aircraft in the world. It's had hundreds of incidents. There is no reason to think that there is any conspiracy going on, and there is not sufficient information to even think that any Boeing specific details were a factor in the incident.
cenamus 16 days ago [-]
But it wasn't there for this reason, and if it was, I'm sure they would have had more than 250m of space to put it at the far ends of the airport.
whycome 14 days ago [-]
“keep fixating” may just be what’s rising to the surface in your algorithm. My own sense has been that the questions are pretty spread out.
boodleboodle 14 days ago [-]
South Korean communities are fixated on this wall issue to an abnormal degree. Discussion of this wall has become a congregation of people who
1. See this tragedy as an opportunity to deride province the airport is located in.
2. Want to be contrarian to those who tell them to wait until official results are out.
3. Feel like the society is "forcing them to mourn" (whatever that means) and would like to look at the cold hard "FACTS".
It's a mess.
16 days ago [-]
s5300 16 days ago [-]
[dead]
tedunangst 16 days ago [-]
How much difference would an additional 50m have made?
SideburnsOfDoom 16 days ago [-]
50m of runway? Not much difference
50m of arrestor bed? Some difference, probably meaningful.
Would an EMAS even work for a gear-up aircraft? EMAS is designed to crush under the pressure of the gear. With all of that load distributed the the engines and along the centerline of the fuselage, would the pressure breach the material?
baq 16 days ago [-]
To be brutally honest, the plane would crash about a second later, so approximately none whatsoever.
But this isn’t the right question to ask, as it isn’t the right question to ask why the wall was there. Why did the pilot and ATC decide it’s a good idea to attempt a gear up landing in the wrong direction is a good start.
EliRivers 16 days ago [-]
I recall back in 2020, when Pakistan International flight 8303 belly landed at Karachi, slid down the runway, and then took off again and had a go at going around, the investigation showed that between them, the pilots just screwed up on having the landing gear down and had a go at landing without it for no other reason than they fumbled it.
loeg 14 days ago [-]
The PIA pilots totally fucked up the approach, missed that they were very high late in the approach, dive bombed down to the runway at the last minute instead of going around. CRM issues -- the senior pilot plausibly couldn't actually fly (he had a history of bad approaches with unsafe descents) and the first officer failed to raise major problems or push back at all on unsafe decisions. When they first touched down gear up, they had dual stick inputs (one pilot was pushing down, one was pulling up) -- this is a huge no no. Communication in the cockpit was awful. Just lots of awful.
After the incident, PIA pilots were audited and determined like 1/3 had fake or suspicious pilot licenses(!!!). Lots of paying other people to pass tests for you. Internationally, PIA has been banned from landing by like all first world countries.
__m 16 days ago [-]
Compared to running into a concrete wall probably a lot
loeg 14 days ago [-]
They'd probably have another 1000m of relatively clear ground without the localizer mound. The brick fence probably wouldn't significantly slow the aircraft, then you have a relatively clear easement (with ILS approach towers, hopefully frangible) until a parking lot and trees on the south coast.
gazchop 16 days ago [-]
I think this is disingenuous reporting.
It’s too early to actually draw a conclusion. We should wait for the full investigation.
There are a large number of compounding problems here. That was just the last one.
16 days ago [-]
thekevan 16 days ago [-]
"... the significance of the concrete wall's location about 250m (820ft) off the end of the runway."
"...the runway design "absolutely (did) not" meet industry best practices, which preclude any hard structure within at least 300m (984ft) of the end of the runway."
"it emerged that remarks in Muan International Airport's operating manual, uploaded early in 2024, said the concrete embankment was too close to the end of the runway."
I mean that was a pretty obvious design flaw that went against common standards. I agree it isn't cut and dry yet but an investigation isn't going to change the above info.
rich_sasha 16 days ago [-]
So it would appear that this structure would be fully compliant if placed 50m further. That's less than a second's difference. The plane would crash into it at the same speed, just a tiny bit later.
OP is 100% right that many, many things must have gone wrong for the position of this structure to remotely matter (human or mechanical errors).
gazchop 16 days ago [-]
I don’t disagree with that. It is a compounding issue but I am much more interested in what happened up to that point. Many many small things or one big thing went wrong for it to even get to that point.
thekevan 16 days ago [-]
But don't forget, that point you mention is the point where the people were killed.
gazchop 16 days ago [-]
There is a whole chain of causality. They were killed by multiple successive problems compounding.
See Swiss cheese model.
thekevan 16 days ago [-]
I'm really not sure the chain of bird strike, belly landing, mid runway landing and fiery explosion are equal parts of that chain. One seems to weigh heavier than the rest.
davisp 14 days ago [-]
Absolutely correct! Had the bird strike not occurred, there wouldn’t have been a crash. Had things with the go around been handled properly, there would have been no crash.
Etc etc. The fact that a wall was 50m out of compliance or whatever it ends up being will be a footnote at best in the review of this crash.
gazchop 16 days ago [-]
There's a few more you're missing there which is the point of the investigation.
copperx 16 days ago [-]
Even with all of the compounded problems, the flight could have been non fatal in most world airports.
gazchop 16 days ago [-]
I wouldn’t state that with any certainty. They touched down 1500m down the runway with little to no braking or reverse thrust. The ending may have been less violent but the outcome may have been the same. I’d rather go from blunt force than being burned alive if a wing ditched and it rolled.
Let’s wait for the investigators. It’s not good to fixate on this outcome.
ckw 14 days ago [-]
This is the landing of United Airlines Flight 232 in Sioux City, Iowa in 1989. It hit the runway very hard, tumbled, broke, left the runway, and burned, but encountered no significant non-frangible obstacle. Of 296 passengers and crew on board, 184 (62%) survived. It is reasonable to assume that given the absence of other significant non-frangible obstacles beyond the ILS mound that loss of life would have been low and potentially zero.
So many things went wrong, and yet the pilots brought the plane down safely – and then this!? Just infuriating.
wat10000 14 days ago [-]
Bringing a plane down safely involves doing it in a way that lets you come to a stop before you crash into something that’s going to kill everyone. You don’t get points for touching a runway at a point where there isn’t enough of it left for you.
No commentary on the pilots’ role here, we don’t know nearly enough to judge. Could be they did a great job and they were just doomed. But the end result is that they didn’t get it down safely.
f1shy 16 days ago [-]
Absolutely no. There is the suspicion that they even shut down the good engine after the bird strike.
mmooss 14 days ago [-]
> Absolutely
> suspicion
"suspicion" seems like fragile grounds for "Absolutely".
loeg 14 days ago [-]
It objectively wasn't a safe landing. How that happened is anyone's guess, until the investigation comes out.
f1shy 12 days ago [-]
Those are 2 sentences.
Lately I’ve seen lots of people doing such snarky comments, without reading carefully, or just writing things that are absolutely illogical… what is going on?!
mmooss 9 days ago [-]
> Those are 2 sentences.
Are you saying the two sentences, in sequence, are unrelated?
> snarky
I wasn't intending to be snarky. My point was serious: 'suspicion' is not grounds for 'absolutely'.
16 days ago [-]
underseacables 16 days ago [-]
They did not bring the plane down safely! The pilot failed to lower the landing gear, or extend the flaps, both of which, for all intensive purposes were technologically possible. Multiple redundant systems for these. I think they completely lost situational awareness, and panicked.
kiririn 14 days ago [-]
>for all intensive purposes
Always a funny one, it's for all intents and purposes
K0balt 16 days ago [-]
When an engine blows up, it’s hard to say what still worked and what didn’t. They aren’t supposed to, but when turbines come apart, there is often a lot of shrapnel that has a history of taking out multiple systems.
But, it is possible that it was a case of poor crew performance.
In any case, the concrete blockhouse at the end of the runway was unhelpful, and it is also outside of the standard guidance for runway aligned obstructions. In most cases, those antennas would have been on frangible towers, and the crew, at fault or not, as well as the passengers, would have had a decent chance of walking away unharmed.
f1shy 16 days ago [-]
There are 3 different hydraulic system plus one electric that can be operated out of a battery… anything is possible, but it seems until now they failed to lower the gear.
underseacables 16 days ago [-]
Something else that may be a factor, a lot of Asian carriers teach their pilots to use auto pilot for landing. American pilots almost universally SOP do not use auto pilot when landing. It's possible the South Korean pilot was using auto pilot to land, forced to do a go around, but wasn't in the habit of manually configuring the plane for landing. That's how the flaps and the gear were both missed. He assumed autopilot etc was handling that.
I think in the cockpit voice recording we are going to be hearing the sirens going off about no landing gear and those guys were just not paying attention.
K0balt 15 days ago [-]
That would be a tragic void in training and procedure. I hope for the sake of the families involved that it doesn’t turn out to be something so avoidable in practice and foreseeable in the carriers operating procedure.
wat10000 14 days ago [-]
There are numerous past examples of this sort of thing. Automation in aviation is really hard to get right. If the automation can fail then the pilots need to be able to perform whatever it was going to do. If the automation fails rarely then the pilots may not get enough practice. But if the automation normally does a better job than the pilots, there’s a tension with letting them get more practice on real flights.
A recent(ish) example is the Asiana crash in SF. They had pretty much perfect conditions for a hand-flown visual approach, but they were out of practice, got behind the airplane, and it snowballed.
There’s an excellent lecture about this called Children of the Magenta Line. The magenta line being the flight path or direction indicator on an autopilot, and the discussion is about pilots who constantly reconfigure the autopilot to direct the plane instead of just taking over. https://youtu.be/5ESJH1NLMLs
f1shy 15 days ago [-]
I’m afraid it will be something like that…
robinson-wall 14 days ago [-]
Which aircraft have flaps or gear controlled by an autopilot? I'm just an armchair "Air Crash Investigations" fan, but I've never heard of any aircraft where either flaps and gear would be automatically controlled by their autopilot. Speedbreaks / spoilers are usually armed and moved automatically on landing.
loeg 14 days ago [-]
There's also a backup manual gear release. But from the degree of control over the airplane demonstrated during landing, it seems likely they had hydraulics.
f1shy 16 days ago [-]
They were with gear down, the retracted it, as part of the go around…
iso8859-1 14 days ago [-]
We don't know that for sure yet. The gear being down is based on an eyewitness report, as far as I understand from Juan Browne. The readout from the flight data recorder will provide a more trustworthy account.
bombcar 14 days ago [-]
If I recall right the video that purportedly shows the bird strike shows the gear down.
loeg 14 days ago [-]
The bird strike (well, compressor stall) video I saw appears to show gear up.
Why did they need to land when they did?
Why did they need to land so soon after the mayday call? (only 8 minutes from mayday to crash, as I understand it)
Why couldn't they land on a longer runway?
Why did they land so far down the runway?
What forced them to land in a clean configuration?
As an airline pilot, these are some of the questions I have. The flight data and cockpit voice recorders should be able to answer these questions.
Though, I am a little sceptical of the claims that it would have hugely reduced fatalities either way. Runway excursions into unmanaged terrain at that speed don't usually work out well for the passengers, even when the terrain appears relatively flat.
I'm not an airline pilot, but I'm still curious to see what caused such an unusual crash, since there doesn't seem to be any single issue that could have caused what happened. So far, my best uninformed guess is a combination of pilot error and bad luck: the approach wasn't stabilised, so they started executing a go-around, and THEN a multiple bird strike caused catastrophic damage to the right engine. This may have led to smoke in the cabin/cockpit which they interpreted as a fire (or some other issue, vibrations etc.) that made them decide to shut down the engine, but they shut down the wrong (left) engine. So now they think they have a dual engine failure. At this stage they obviously don't have time to run through paper procedures, and they put the plane into clean configuration to maximise glide and attempt a 180 to try and land back on the runway. Then they either couldn't or forgot to deploy the gear, and floated down the runway partly due to ground effect from being at an unusually high speed, thus landing at high speed almost halfway down the runway. Thoughts?
<https://en.wikipedia.org/wiki/Normal_Accidents>
Either 8 character passwords are fine and secure, or bad and should be banned? With no context between “€x8;,O{w” and “password”?
I suspect runway design has more variables than just distance to obstacles.
... you can't be serious with this? 300 more feet of unused runway is equivalent to if not better than 300 feet of buffer. You're fixated on following the "rules" without any understanding as to why they exist.
If they'd shortened the "runway" by 300m (let's say the unused space was still tarmacked and empty, but not designated as a runway, although I understand there are better materials for arresting overruns) would all those people still have died and would people still be blaming the airport layout?
Perhaps the pilot would have made a different decision if the runway was advertised as 2500m instead of 2800m, but that also suggests people are looking at the wrong thing, and pilots looking for emergency landings should consider not only the runway length but also any buffer available.
https://multimedia.scmp.com/embeds/2024/world/skorea-crash/i...
What they were saying is that just because other airports feature runways situated next to natural obstacles and this is allowed and equally dangerous, it doesn't mean this airport needed to have this particular, deliberately designed and implemented obstacle next to the runway.
The reason for the concrete-reinforced berm was typhoon resilience. It begs the question whether there are alternative designs that are trade of requirements better.
As an aside, this reminds of the consideration highway bureaus in the US give to trees and poles.[1] Trees are removed and poles should break easily and fall after a vehicle impact. This comes to mind because I have given most thought to these considerations as a pedestrian, regretting tree removals and feeling exposed to passing cars in a system designed to accommodate them safely (for them) departing the roadway anywhere, anytime. Of course, sometimes broken poles fall on cars or people, power outages are more routine especially after vehicular accidents, and there are other tradeoffs too, some of which are safety-related.
[1] https://safety.fhwa.dot.gov/roadway_dept/countermeasures/saf...
(Assuming the math is correct:) That's the average speed over that distance. The plane would have been slowing down the whole time.
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 is based on velocity squared, so every bit helps a lot.
Or as an adult. I am on a diet though.
And good news! A fully-loaded 737-800 has a maximum takeoff weight of less than 80 tonnes, not thousands, so your challenge is much more attainable!
<https://en.wikipedia.org/wiki/Boeing_737_Next_Generation#Spe...>
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).
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
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.
[1]https://s.france24.com/media/display/579312a0-c8cb-11ef-81bd...
Minor nit, I believe it’s called the teardrop go around for such cases. You also have the impossible turn which is meant typically for engine/power failure during takeoff, and it actually is possible to be safely done - as demonstrated by the former ALPA Air Safety Institute Senior VP Richard McSpadden in one of his YouTube videos.
However, it can be deceptively difficult to have the right conditions to pull it off - as demonstrated by the ironically fatal crash that killed Commander (Ret) McSpadden (though iirc it was not clear if he was flying the craft at the time).
(Edits made for clarity/content.)
I don't know if we could expect the pilot to know about or expect the barrier there.
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.
But it's definitely part of the program.
They must also sit on the tarmac post heavy braking and the brakes must not burst into flames.
[0] https://www.youtube.com/watch?v=evLpE8Us-j0
Commercial jet aircraft utilise thrust reversers, speed (or air) brakes (usually control surfaces which can extend out from the aircraft fuselage or wings), and landing gear brakes.
The latter are not insignificant, but thrust reversers and speed brakes are major contributors, especially immediately after touchdown.
There's also the effect of spoilers which increase the load over the gear and hence the braking capabilities of landing gear brakes.
Jeju 2216 failed to utilise nearly all of these mechanisms. It landed without flaps, spoilers, or gear, and possibly w/o thrust reversers.
That's a lot of weight but nothing crazy, so on a dry runway wheel brakes alone are more than enough to stop normally. They would also wear out a lot, overheat and occasionally ignite if used like that, so that's what thrust reversers are for.
It's also definitely the case that the cement-reinforced dirt mound is not best practice for a locator array.
Some of them even move around the recommended touchdown point depending on other factors, if the runway is extra long.
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.
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.
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
Compared to that mall collapse, a berm that far off the end of the runway won’t even be notable.
They used a HIGHLY flammable material to completely cover a raised highway.
(All of that said, I read from so many people now that the plane would have disintegrated once it did finally start to drag given the speed, and there is another parameter wall shortly after the berm.)
Edit: we've had to ask you many times to stop breaking the site guidelines:
https://news.ycombinator.com/item?id=38198402 (Nov 2023)
https://news.ycombinator.com/item?id=37367901 (Sept 2023)
https://news.ycombinator.com/item?id=36896498 (July 2023)
https://news.ycombinator.com/item?id=35759087 (April 2023)
https://news.ycombinator.com/item?id=34698866 (Feb 2023)
https://news.ycombinator.com/item?id=25128446 (Nov 2020)
Eventually we have to ban accounts that keep doing this, so please stop.
11th out of 15 total, servicing about 4 flights / 630 passengers per day on average using the very same statistics you've linked. That sounds like a pretty small airport to me, both in absolute and relative terms.
"International airport" means very little outside of large nations like the US, Russia, Canada, Brazil or China. Most nations are small enough that there's at least as many foreign airports within a few hundred kilometers as there are domestic ones, and therefore every airport may as well be an international airport.
In the U. S., at least, "international" just means there's a customs station. There are some pretty small airports that have "international" in the name. Fairbanks, Alaska, comes to mind.
It's... a tiny airport, both by commercial standards and by South Korean standards.
Pretty sure you're just trolling though, no way this is a serious comment.
Stinks of bad crew resource management and ATC which is why the ATC and airline for raided by SK officials.
If there were significant winds it would have compounded those factors.
It is curious that the gear was retracted. I can only think that this was due to some kind of system failure? Perhaps that same failure explains the decision to double back instead of going around?
Lots of questions, hopefully there will be answers.
Still, the structure does not seem to meet the standard for frangibility that is indicated for objects in the approach path within 300m, although it’s not like it was at the very end of the runway.
Runway over/undershoots are actually quite common, and the building of a nonfrangible structure on an otherwise safe skid zone is a significant error in design principles that is not common or conformal to industry standards.
If those antennas had been placed on property designed towers instead of a concrete bunker, the passengers and crew very well may have walked away without a scratch, despite any errors on the part of the crew or procedures of the airline.
"TransAsia Pilot Shut Off Wrong Engine Moments Before Crash" (2015)
Taiwan aviation officials on Tuesday released a detailed report of how the pilot mistakenly shut off the plane's only working engine after the other lost power. "Wow, pulled back the wrong side throttle," the captain said shortly before crashing.
<https://www.buzzfeednews.com/article/jasonwells/transasia-pi...>
I seem to recall a Mentour Pilot episode (YouTube channel) describing either that or a similar incident.
Point being that when things start going very wrong you've got to actively think to prevent making them worse.
That said, I have seen some absolutely horrendous responses to emergencies go from kinda bad to massive destruction of property, so much so that unless one has trained for the specific emergency, the best course of action is to assess way more than you think you need. And we often have more time than we think, and we make the the right decisions, they are the right decisions because they give us more time.
Landing gear has a manual gravity release by the first officer that doesn't require the hydraulics. (But does take some time.)
Ground effect was certainly involved (why they glided so far before touching down) but the bigger factor was their high speed, lack of flaps, and lack of gear.
You have to reach all the way back to do it, difficult to do with all the other shit going on.
That's why EASA says put the plane down if there’s a strike on approach. Ryanair 4102 is a good example of a close one there as a reference.
ETA: The primary footage is hard to find now that the topic is so saturated, but there is a specific clip from a close vantage where it is highly visible. I'll include a link if I can find it.
People often have an idea that ATC actually controls what happens. They just give advisory guidance to pilots, who ultimately decide what to do. A clearance to land or the lack of one does not absolve the pilots from making their own judgments and decisions about how to conduct the navigation of the aircraft, and where and when to land.
Usually, it’s a bad idea to not follow ATC guidance, but in the case of emergencies especially, pilots call the shots.
But the tower at an airport, their job is to supply information, and once you call mayday you’re in total control - you can ask them to do whatever you think will help you save the flight, including (and usually automatically done) diverting all other flights, clearing all runways, and cancelling any departures pending until the issue is resolved.
Pilots have to be trained to ignore ATC as necessary, because planes have crashed because of trying to be polite to requests (and not declaring mayday or pan pan).
> no idea he had to make the approach in the opposite direction.
So the wall is actually at the beginning of the runway. That wall was never never meant to be at the end of a landing but at the start of landing.
I don't understand why this isn't made clear. Basically the runway was used against the design specifications.
You always want to land with a headwind and never a tailwind, so ATC will use whichever end is favorable for the current conditions.
In this case, if they attempted to land with a tailwind then the on-heading vector component of wind velocity must be added to the airspeed to get the ground speed... whilst this was a contributing factor to the accident, it's not something to focus on.
There will be a thorough investigation but it will take some time to get answers.
If that's right then OP would be correct in saying, this direction wasn't meant to be used.
Part of preflight is investigating those so you know what are options at what are not - entirely closed runways will be indicated if they’re actually broken up or just marked closed.
Sure, but so is a highway, or a river. Doesn't mean those should be built to runway standards.
It should perhaps be pointed in news coverage since I equated "opposite direction" with "wrong direction" - hence my scepticisms about the wall.
Do you mean at Muan?
We don’t know why the pilot elected to double back instead of go around. There may have been indications of a progressive failure that indicated that course of action, but it does seem hasty. That haste may have caused them to not be able to set up a stabilized, minimum speed approach, and may have contributed to the long touchdown, which certainly was a contributing factor.
Still, a 14 ft high concrete structure within 300M of a runway end is unusual, and does not fit the standard for frangable structures which is the guidance for runway aligned equipment.
There are airports in which approaches always or very nearly always follow the same profiles given local conditions. SFO, SJC, and SAN would be three examples off the top of my head.
SFO's major approaches are over the bay, opposite approaches would involve rapid descents dictated by mountains near the airport.
SJO and SAN are both limited by proximate downtowns with tall towers. Nominal approach glide paths cut below the rooflines of several structures, and make for some interesting experiences for arriving travellers.
What’s noteworthy, there’s a note to use extreme caution due to this wall if landing or taking off towards it.
https://web.archive.org/web/20241215000000*/https://aim.koca...
Are we expected to believe these pages never got crawled before?
Can we learn a forensic lesson for this and automatically snapshot similar pages for all runways worldwide?
it seems this is the same structure:
https://en.wikipedia.org/wiki/Jeju_Air_Flight_2216#Non-stand...
3800 - 2800 = 1km.
Did the plane skid for 1km before crashing into the obstacle?
Airports like this are designed to have two approach directions -- in this case, 10 and 190 degrees. Either approach direction would have been acceptable depending on the prevailing wind.
https://youtu.be/3D9BDIH553U
Maybe it's the cheapest way to engineer the ILS localizer to be flood-resistant? I don't know.
The runway should be as long as it’s required to be. If after (and before) the paved runway they need a length of open space, that should be however long it is required to be, too. Beyond that there could be a minefield, a pillow warehouse, an ocean, a mountain, etc. It shouldn’t matter.
Only infinity billions of dollars for each airport and likely cause other issues, but, progress!
Nothing about this crash was normal, and talking about a thing past the end of the runway is misdirection.
This did not happen on this flight
I don't know what happened in this event, but the concrete box is painfully uninteresting compared to basically anything that happened before it.
At no point was this landing fine or by the book, and talking about ground obstructions is just a way to distract you.
It might be more useful to start with the solid concrete plane stopper and work backwards than work forwards from 1903.
If there had been enough engine power to control direction on the ground, there might also have been enough power to remain airborne, but based on limited information, that wasn't so. Under the circumstances the pilots would have wanted to stay airborne to buy time for a more controlled descent, were that possible.
All these speculations are preliminary and may completely change once the black box information is released.
Sure about that? 160kt (how fast someone calculated it went off the end of the runway) is way above Vs1 for a 737, there should be plenty of rudder authority. Heck, Vapp is usually in the 130-150kt range.
If they were trying to take off again, there wasn’t any hope.
I found this comment helpful from a Reddit thread.
>The embankment is there to protect the road from the jetblast of departing aircraft in oposite runway direction. Thats why it is allowed directly in the safety area.
Show you working. Not feelings because people don't have intuition for such unusual motion. You could equally have said "a few hundred meters would be enough."
Stopping time: t=v/a, t=77/2. Stopping distance: d=v^2/2a, d=77^2/2*2
Because you seem unaware: Airplane wheels have very powerful brakes!
Hm, the stiction page on Wikipedia does not explain how it relates to braking. Maybe check out https://en.m.wikipedia.org/wiki/Threshold_braking
Look it feels like you want to win an argument. You can only win it for people who do not understand the difference between static friction of a tire on tarmac and kinetic friction of a hull on tarmac. I couldn't tell you off-hand which has more friction, but I'm ready to believe by example that the hull has bad properties when it comes to braking. It's made for low friction after all.
https://maps.app.goo.gl/BN15aSQ1pW6vJkzb7
I don't think people who say that it's a bad idea to have a concrete wall at the end of the runway argue the plane should make its way to a nearby motorway. I think most refer to using EMAS, ie a crushable concrete floor in which the plane sinks and stops.
but was it the end of the runway? As I understand, the pilot came in from the opposite direction, i.e.
> The pilot then aborted the original landing and requested permission to land from the opposite direction.[1]
So that wall was located at the beginning of the runway if the runway was used correctly.
From the bottom image[2], it would appear the wall is located behind the point where planes begin their take-off (and I assume their landing) - but I'm no aviation expert.
[1]: https://www.bbc.com/news/articles/ckgzprprlyeo [2]: https://ichef.bbci.co.uk/news/1536/cpsprodpb/9090/live/ab9db...
Most runways are intended to be used in both directions depending on the wind. This one doesn't seem to be an exception?
50m of arrestor bed? Some difference, probably meaningful.
https://en.wikipedia.org/wiki/Arrestor_bed
But this isn’t the right question to ask, as it isn’t the right question to ask why the wall was there. Why did the pilot and ATC decide it’s a good idea to attempt a gear up landing in the wrong direction is a good start.
After the incident, PIA pilots were audited and determined like 1/3 had fake or suspicious pilot licenses(!!!). Lots of paying other people to pass tests for you. Internationally, PIA has been banned from landing by like all first world countries.
It’s too early to actually draw a conclusion. We should wait for the full investigation.
There are a large number of compounding problems here. That was just the last one.
"...the runway design "absolutely (did) not" meet industry best practices, which preclude any hard structure within at least 300m (984ft) of the end of the runway."
"it emerged that remarks in Muan International Airport's operating manual, uploaded early in 2024, said the concrete embankment was too close to the end of the runway."
I mean that was a pretty obvious design flaw that went against common standards. I agree it isn't cut and dry yet but an investigation isn't going to change the above info.
OP is 100% right that many, many things must have gone wrong for the position of this structure to remotely matter (human or mechanical errors).
See Swiss cheese model.
Etc etc. The fact that a wall was 50m out of compliance or whatever it ends up being will be a footnote at best in the review of this crash.
Let’s wait for the investigators. It’s not good to fixate on this outcome.
https://youtu.be/sWkU6HRcOY0
https://en.wikipedia.org/wiki/Endless_runway
No commentary on the pilots’ role here, we don’t know nearly enough to judge. Could be they did a great job and they were just doomed. But the end result is that they didn’t get it down safely.
> suspicion
"suspicion" seems like fragile grounds for "Absolutely".
Lately I’ve seen lots of people doing such snarky comments, without reading carefully, or just writing things that are absolutely illogical… what is going on?!
Are you saying the two sentences, in sequence, are unrelated?
> snarky
I wasn't intending to be snarky. My point was serious: 'suspicion' is not grounds for 'absolutely'.
Always a funny one, it's for all intents and purposes
But, it is possible that it was a case of poor crew performance.
In any case, the concrete blockhouse at the end of the runway was unhelpful, and it is also outside of the standard guidance for runway aligned obstructions. In most cases, those antennas would have been on frangible towers, and the crew, at fault or not, as well as the passengers, would have had a decent chance of walking away unharmed.
I think in the cockpit voice recording we are going to be hearing the sirens going off about no landing gear and those guys were just not paying attention.
A recent(ish) example is the Asiana crash in SF. They had pretty much perfect conditions for a hand-flown visual approach, but they were out of practice, got behind the airplane, and it snowballed.
There’s an excellent lecture about this called Children of the Magenta Line. The magenta line being the flight path or direction indicator on an autopilot, and the discussion is about pilots who constantly reconfigure the autopilot to direct the plane instead of just taking over. https://youtu.be/5ESJH1NLMLs
https://x.com/Global_Mil_Info/status/1873181671375421703