The two people who survived were in the tail section.
They did not hit the barrier wall surrounding the aiport. Instead they hit an antenna/navigation structure which was built on a earth/concrete berm. Obviously this structure could have been built so it would break off if hit by a plane instead of being such a massive structure that would instead destroy an airplane.
For informed discussion see the thread at:
Several of the posters there have difficulty seeing how mechanical problems alone could have caused this massive catastrophe–instead that the pilots made errors in how they responded.
I see, the antenna structure. But maybe in the future they could also build the embankment in a sloped way, such that if an airplane hits it it would slide up on the embankment instead of like smashing a wall. If the goal is to keep out intruders, then the other side of the wall could be a 90-degree normal upright angle wall, but the side that the plane would hit into should be a slope.
Video appears to show no flaps/slats deployed, and the plane skidding very fast, consistent with deliberate a no-flaps, no-slats landing approach. Between that and the gear problem, maybe these were both caused by a major hydraulic system failure? The investigation will hopefully provide more definitive answers in a few months’ time, but at this point I can’t see what the pilots could have done differently.
Somebody built the embankment for a reason. We just don’t know what that reason was/is. All the antenna structures scattered around at least US airports are fairly frangible. Then again airplanes are fairly fragile.
A planned gear up no flap landing in a 737 makes no sense in any scenario I can conjur up. Both flaps and gear can be deployed in the absence of hydraulic power via backup systems. If somehow you had a major fire onboard and were in a major “screw the checklist, let’s land!!” hurry to get on the ground, you’d still do better to lower gear somewhere before touchdown.
This one is going to remain pretty mysterious until at least the preliminary report comes out.
But that is different. I do not think the Southwest plane knew of their problems before landing.
I’d think the Jeju pilots did know they had no landing gear. I then wonder why they didn’t divert to an airport with longer runways and (maybe) some safety equipment that could have helped?
Agreed; it’s not really an identical incident. I had shared that information as another example of a plane which wound up hitting a concrete wall at the edge of the airport property, because it was unable to stop before running out of runway (for, as you note, different reasons), and @Velocity wondering why there would be a concrete wall there.
One change which Midway implemented after that incident was placing crushable concrete blocks in between the end of the runways, and the concrete walls, to provide an additional safety measure to slow down an out-of-control plane before it could reach the wall.
What if only some of the landing gear could go down? I.E. You can’t lower one of the back landing gear no matter what is tried. Is it better to belly land or land on one gear and tip over to the side where the gear would not come down? (really asking, I do not know)
The 737 book answer is more gear is better, regardless of geometry.
There are independent mechanical emergency lowering systems for each of the three gear. If the normal hydraulic gear system was simply inoperative, they could try the mechanical (free fall) system and each leg would succeed or fail on its own merits; there’s no mechanism in common between them.
The way(s) all 3 alternate gear extension systems could fail is a) they weren’t tried at all, b) the crew did each of the three of them wrong versus the very simple instructions in their emergency manual, or c) the normal hydraulic system was actively holding all the gear up due to a malfunction of its valving. Which would be a novel failure on a 737 feature new to the MAX, but common to all 767-400s, 777s, and 787s ever built.
The flaps likewise have an independent extension system that relies on backup hydraulic and electric power. And in general with a flap malfunction the book answer is land with as much as you can get while retaining symmetry between left & right. There is a mechanical linkage that should maintain symmetry by brute force but even that could theoretically fail.
If we assume the gear was no kidding stuck up despite all proper procedures being applied, the gear up landing checklist directs a landing with maximum possible flaps.
If we assume the flaps were no kidding stuck up despite all proper procedures being applied, the flaps reduced-or-fully-up landing checklist directs a landing with maximum possible gear.
Both being fully up bespeaks great haste or great confusion. A long landing that slid off the end adds to the impression of confusion or panic being in command, not the captain.
I 100% believe this and I am sure Boeing (and Airbus as well) have really explored this problem and decided it is the best way. I can see landing on some gear will slow you down faster than no gear as well as absorbing a lot of the impact force which they are designed to do. But, there will come that moment with the side with no gear tips over and the wing grabs and the plane spins and/or flips which can’t be good.
We see in the Jeju video the belly landing went great. The plane was fine (considering the circumstance). It just ran out of runway. If it had a long enough runway or (maybe) crushable concrete at the ends ISTM that is better than spinning out.
But, if it was not abundantly clear, I am not an expert in this (far from it) and I have to think Boeing/Airbus have given it all much more expert thought and settled on the best set of instructions for pilots to follow. Just seems weird but that’s ok. Not all things are intuitive.
Watching the video, it seemed to me (though, I am not a pilot or aviation expert by any means) that, while the belly landing seemed to be “clean,” the plane was still moving at a pretty high rate of speed when it landed. If so (particularly if they were going faster than would be recommended for a no-gear landing), that may have doomed them to run out of runway before they stopped.
At this point, we’re all speculating, but I think @LSLGuy 's take will probably wind up being close to the truth of the matter: either there was a series of catastrophic failures within the plane, or the crew in the cockpit made poor and/or panicked decisions.
I’ve heard/read some accounts to the effect of a sequence that (1) the tower reported flocks of birds, (2) the plane sent out a mayday, (3) the plane made the belly landing.
How would a bird strike take out the landing gear’s ability to deploy?
If we assume something like the Sullenberger USAir ditching in the Hudson that might make sense and convert the crew from goofs to almost-heroes that almost saved the day.
Assume they’re flying along normally, not having yet arrived at the appropriate point(s) in their routine arrival to begin deploying flaps or gear. They go through a big bird flock, and one or both engines crap out. Or one quits and the other ain’t soundin’ so good.
Now they have a real circus on their hands. There are procedures for single & dual engine failures. And for “one engine ain’t soundin’ so good”. Gotta decide which is applicable and use it pronto. Meanwhile somebody needs to keep flying. And if it seems like getting even one fully healthy engine is unlikely, deciding where / how to land this thing before the second engine quits outright.
In general in that scenario you want to pick a suitable place to land, and remain flaps up & gear up as long as you can. Or said another way, you want to pick a suitable place you think you have more than enough glide range to reach. Then as you glide towards it at constant speed, if you are sliding low/shallow, you won’t make that spot. Pick another suitable one closer or die trying. If you are slowly sliding higher / steeper, you need to increase drag to not overshoot. So add some flaps and reevaluate. Lather rinse repeat until the ground arrives.
If they picked a spot (the airport) that was almost too far away, they might find themselves still gear & flaps up and barely 1/2 mile from the runway. And rather suddenly that excess energy they’d been husbanding “just in case” turns into a giant problem. They can’t burn enough of it with drag in the time/space remaining, so they’re committed to a high speed touchdown on the runway or a more normal touchdown a mile or two beyond the airport.
There is zero simulator training or usable tech guidance on total engine out glides. Folks who’ve been flying a type for a couple years can arrive at some good guesses, but it’s all eyeball & thumbnail stuff, not computation. And the natural inclination of darn near any pilot will be to want to get there with (some) excess energy rather than too little. The crisis occurs when some extra becomes too much extra noticed too late.
All in all a bad day at work for those dudes, whether they were almost-heroes or goats.
Do those procedures include getting the landing gear down?
If no hydraulics it seems a gravity drop. I have seen small plane pilots manually crank gear down and it was a huge pain in the ass and took a long time. I can’t imagine trying that on a commercial jet (if it is even an option).
With one engine running you have plenty of hydraulics and electricity and thrust to proceed more or less normally and unhurriedly to do all the normal arrival approach and landing tasks at the more or less normal cue points in the flow of events. If you knew you had, or discovered during the approach that you had, a need to fuss with manual gear or flaps, you just drone around in circles and accomplish that procedure also at your (relative) leisure. There is not haste to land. It’s much more important to do the fairly intricate job of emergency management right the first time.
With no engines your goal is to get one running (along with the faster-starting APU) and aim for something soft while expecting your day to end badly. It is telling that the dual engine failure procedure comes to an end with only two cases: both running, or one running. There is no case for “none running”.
There is guidance for ditching which addresses procedures for maximizing buoyancy and the best way to approach the difficult task of landing on rough or smooth water with poor height perception. With or without engine(s) running, but engines running greatly improve your odds of success.
There is no guidance whatsoever for unpowered or off-airport landings. Which is probably a combo of: 1) vanishingly unlikely to occur, 2) in that impending circumstance, the crew won’t have time to read any guidance, 3) anything they say would still amount to “Good luck John Wayne”
Overall I am reminded of the procedure for a night forced landing in a small plane:
Descent to 50 feet above the surface.
Turn on the landing light.
a. If you like what you see, land.
b. If you don’t like what you see, turn off the light.
Thanks for the explanation LSLGuy. Sounds like the pilots had a worst-of-all-compromises situation, where they had just enough energy to cause a fatal crash but not enough energy to truly have good options, and not enough distance or time to make a good decision.
Still, though - no matter how many blunders the pilots made, the embankment/wall/antenna that the airport designer put there ultimately caused most of the deaths. If the pilots had had something much flimsier to crash into, we might be talking 0-10 deaths today instead of 179. Wonder if this is going to lead other airports to start to change what things they put at the end of their runways, or put speed-bump like things to slow down a similar impact.
Again, we have no idea now if birds or engine problems were involved. That is all speculation by media and by me. I’m discussing what would probably unfold after that assumed event occurred.
Airports are already designed with lots of features to reduce crash severity once an airplane leaves the prepared surface. I can’t speak to that airport in particular, but whatever is there is that way for a reason. A reason that included understanding how it was helpful or hurtful to airplanes running into it.
From other information I’ve seen, its speed increased shortly before touchdown to about 158 kn (182 mph). Runway 01/19 is only 2.8 km long – not particularly short, but significantly shorter than a lot of major airport runways. If they used up too much of the runway before touching down at that speed, they may have been doomed even under the best of circumstances. That would be well over 60 to 70 tons of mass trying to come to a stop from 180 mph with no brakes and no thrust reversers.
Obviously if the flight crew had known the likely outcome, almost any alternative would have been better, including a “Sully” Sullenberger attempt to ditch into the ocean. It’s pretty clear that despite the flight crew being probably blameless for whatever precipitated the accident, they likely did a lot of things wrong in its aftermath.