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Third attempt, no diversion, no report of fuel emergency, landing in TSRA but with decent visibility and a very long overrun UNDER the localizer and almost to the fence.
But it hung on to the mains and the engines, so maybe the length of the overrun is more due to the slippery mud factor than the speed. A miracle there were no injuries, especially to the pilots.
They had been holding for 55 mins after the first go-around and 42 mins after the second. I expect they weren't interested in a third one. -
I was going to say that there has to be something else to the story because they landed in a long runway (3.2km, or 2 miles, or 10500ft) with a slight 5 to 10 kts headwind and still departed the end of the runway at 80 kts. So they lost just 60 or 70 kt of ground speed in 2 miles? That sounds like no breaking action whatsoever, not from the wheels, not from the engines. Even more, it sounds like rolling friction and aerodynamic drag alone should be enough to slow the plane much more than that in that distance, except that if the reversers are not deployed (at least in idle) you will have forward idle thrust that will more or less compensate for that. Although I have no actual idea, 80 kts sound like a reasonable "equilibrium speed" where idle thrust would cancel aerodynamic drag and rolling friction. In that scenario, the length of the runway doesn't matter, you are not stopping (unless you shut down the engines).
Then someone copied in AVH the comment posted somewhere else by someone that claims having been a passenger in that flight, and it is compatible with a set of failures that left the plane with no brakes and no reversers. It involves a hard landing, which could potentially damage the brakes themselves so it doesn't matter if you have a hydraulic system feeding them or an accumulator, the brakes would not work. But then the damage also caused the reversers to be inoperative? Was there extensive damage to multiple hydraulic systems? Or the hard landing also damaged the sensors that detect that the plane is on the ground and enable the deployment of the reversers?
This is going to be interesting. That a single action (a hard landing, which however is not as hard as to destroy the landing gear itself) can cause a combination of failures that can render the plane unstoppable looks like an oversight in the design of the plane.
But maybe it was something else. Let's wait for the final report. In the meantime, here is the post of the passenger:
http://avherald.com/h?comment=50004095&opt=0
Initial approach to the islands was met with frequent lightning. My wife and I were taking photos and video out the windows until turbulence began. This persisted as we descended through the clouds for the 1st final approach. I remember viewing the detailed city lights as the fog cleared, and then the pilot throttled up like top gun and aborted before we came near the runway.
We circled back around for a second attempt. This time, he went for it. The conditions were similar: shaky approach and fog. I noticed he began to pitch back just before hitting the runway. Perhaps he noticed we had a fast approach? The impact was a single loud bang, louder than any rough landing I’ve ever experienced. Again, he throttled out of there and began the circle around.
At this point, I had my wife shut the window. The pilot then came on the intercom telling the crew and passengers to prepare for emergency landing procedures, and to listen to what they say. I told my wife it’s time to start praying. I monitored our ETA on the seat monitor in front of me. That emergency landing announcement came at roughly 13 minutes to the 3rd arrival, and we received no further communication from the pilot or crew until final approach.
Going through the clouds was very shaky, as before. Once we cleared the clouds the final time, the attendants began shouting, “HEADS DOWN, STAY LOW!” repeating in both Korean and English. I recited a few Hail Marys with my wife. This lasted until touchdown, which was completely smooth, unshaky, and a buttery impact. Passengers began clapping at the seemingly anticlimactic result, since we were bracing for the worst.
As we were rolling, I slid the window up and quickly noticed a few things:
Our ground speed was relatively slower than I’ve ever seen.
I did not feel any braking force. I could sit up straight without resisting a forward force.
I did not hear the engines engaging, or revving up, for reverse thrust.
I had my wife and I resume safety position just as the flight attendants started back with the shouted instructions again. Time felt simultaneously slow and fast. We placed the complimentary pillows between our heads and the seats just before we ran off the end of the runway. The grinding halt felt like it lasted roughly 5 seconds.
After we stopped, the crew ran to the side windows to inspect the wing damage, and emergency evacuation followed. We were told to leave our carryon bags w/ passports, and we all exited via the inflatable slides. We made our way through the sloppy, wet grass onto a service road around the perimeter where we were bussed to the airport.
I could go on about the immigration/passport process, but we are still being detained in a hotel, so I’ll try and provide a follow up once that finishes. It sounds like they are still investigating the crash and nobody is allowed to retrieve luggage or carry ons at the present moment.
--- Judge what is said by the merits of what is said, not by the credentials of who said it. ---
--- Defend what you say with arguments, not by imposing your credentials ---Comment
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Is it possible the landing gear could have suffered significant damage on the second approach? Is there any footage of the third approach showing main gear intact?Comment
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Aha, so a touch and go on the second run. Indeed, it sounds like something got bent there. If you are right about the air/ground sensors failing to detect ground upon touchdown, the engine idle will also remain in flight idle, not ground idle, per the LGCIU/FADEC interface. The witness decription doesn't seem to align with that, as he claims "ground speed was relatively slower than I’ve ever seen".Originally posted by Gabriel View Post
This explains the long (42 minutes) gap between the 2nd and 3rd attempts. They probably suspected LG damage (maybe lost the green lights) were working the problem and and were concerned about gear collapse. I'm guessing they intended to touch down very lightly at minimum ground speed and ended up floating too far down the runway. And then... why no braking?
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If the testimony of the self-claimed passenger is anywhere near accurate, it almost certain that there was some kind of damage in some parts of the landing gear from the second approach that end in a rough "touch and go". And that damage caused the airplane not to be able to use the brakes or reversers in the landing after the 3rd approach.Originally posted by flashcrash View Post
It also sounds like there was no extensive damage to the tires, wheels and supporting structure, since the final touch down and roll out seems to have been very smooth, per their testimony.
--- Judge what is said by the merits of what is said, not by the credentials of who said it. ---
--- Defend what you say with arguments, not by imposing your credentials ---Comment
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I don't know, of course, but it is going to be interesting. With a largely intact plane, the affected parts of the affected systems will be able to be recovered in good shape and analyzed in detal, the CVR and FDR can be recovered, as well as the non-volatile memory of a myriad of different systems in the plane including, especially, the QAR, plus you have 2 pilots, several flight attendants and a couple hundred passengers from which you can obtain testimony, plus maybe some video footage? It should be possible to do a super deep investigation and get to the bottom of this both from a design standpoint as well as an operative one. It requires the will and budget, though.Originally posted by Evan View Post
Aha, so a touch and go on the second run. Indeed, it sounds like something got bent there. If you are right about the air/ground sensors failing to detect ground upon touchdown, the engine idle will also remain in flight idle, not ground idle, per the LGCIU/FADEC interface. The witness decription doesn't seem to align with that, as he claims "ground speed was relatively slower than I’ve ever seen".
This explains the long (42 minutes) gap between the 2nd and 3rd attempts. They probably suspected LG damage (maybe lost the green lights) were working the problem and and were concerned about gear collapse. I'm guessing they intended to touch down very lightly at minimum ground speed and ended up floating too far down the runway. And then... why no braking?
--- Judge what is said by the merits of what is said, not by the credentials of who said it. ---
--- Defend what you say with arguments, not by imposing your credentials ---Comment
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