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Author Topic: Jeju crash.  (Read 566 times)

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Doctor Gollum

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Jeju crash.
« on: 30 December 2024, 17:01:11 »

Before it suffered the bird strike, the flaps were deployed and it was on a stable final approach and the only thing left to do was drop the gear and land.

After the bird strike, the only extra thing was to possibly pull the fire handle for that engine and shut the fuel off.

They'd have landed relatively normally into the wind had full wheel braking available along with the wing spoilers and everyone would have gotten off non the wiser.

Instead, they fly for another five minutes, raised the flaps and kept the gear up before attempting a belly landing with a tail wind and two people barely survived.

Either significant pilot error or murder/suicide.

And before anyone says anything about the mechanical condition of the aircraft, they had enough control to raise the flaps, fly past the airport, perform a 180° turn and crash along the runway.

The concrete reinforced berm across the runway might have been the final hole in the cheese*, but there were plenty of opportunities to not end up there.

*Reasons Swiss Cheese model. Also, without the berm, I suspect that every one would probably have survived except possibly the flight crew.
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Re: Jeju crash.
« Reply #1 on: 30 December 2024, 18:26:19 »

All very strange.

No end of bookings cancelled ( 68,000?) and it was a Boeing !

How did the two cabin crew survive?  Were they sitting with their backs to the front.?
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Doctor Gollum

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Re: Jeju crash.
« Reply #2 on: 30 December 2024, 19:18:12 »

All very strange.

No end of bookings cancelled ( 68,000?) and it was a Boeing !

How did the two cabin crew survive?  Were they sitting with their backs to the front.?
The aircraft manufacturer is completely irrelevant. The aircraft was 15 years old and used to belong to Ryanair. Not that that is particularly relevant either, it could have easily been an Airbus A320 and the result would have been the same.

As to the crew surviving, facing rearwards is a large part of it.

Basically the tail section that remained intact is very specifically arranged. From the back you have:
1. The pressure bulkhead.
2. The galley structure bolted to the floor and fuselage.
3. The rear doors in their reinforced frames.
4. The two rear facing crew seats, one each side bolted to the floor and bulkhead.
5. Separate bulkhead either side bolted to the floor, fuselage and toilet structures.
6. Two toilet structures bolted to the floor and fuselage.
7. The rest of the aircraft.

Where the tail structure separated, was immediately ahead of the toilets. Basically the nose smashed through the berm stopping almost instantly. The rest of the aircraft broke apart as it compressed into the back of the nose section.

The deceleration from the final impact would have killed everyone pretty much instantly for what it's worth, And the recovery team have a horrific task ahead of them with 30 rows of seats stacked together. Anyone identifiable would have been sat towards the rear.

The crew that survived were attached to a rigid bulkhead by four point harnesses and as long as all the galley equipment was restrained correctly, then they were reasonably well protected. Also the deceleration forces would have been much lower at the tail thanks to 95ft of compression absorbing the impact. The most dangerous thing for them would have been if someone had successfully opened the rear doors due to the way that the evacuation slides work on the 737. Had they been forward facing they would have been sat behind the door line so would have still had protection from the structure around the doors, ie nothing immediately Infront to impact against.

If it was still configured as Ryanair ordered it, then the front crew would have been sat facing the passeges with no bulkhead, if there was a bulkhead in place they might have survived the impact and stood a chance.

Looking at the crash site photos, the nose section survived quite well considering, as the front doors are still attached to the flight deck, and on the Ryanair spec 737s they have built in stairs, so that front area is reinforced compared to aircraft without the stairs.
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Re: Jeju crash.
« Reply #3 on: 30 December 2024, 20:11:51 »

You should change jobs,, Go and be a crash scene investigator..
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LC0112G

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Re: Jeju crash.
« Reply #4 on: 30 December 2024, 21:28:21 »

The 'best' explanation I've heard on the spotter grapevine so far is....

They were warned by ATC of birds on their initial approach. They saw a flock of birds and decided to go-around. The go around was initiated before the filmed bird strike occurred. They were already too fast/high to land of that initial approach when the bird strike happened, so had little choice but to continue. In any case, SOP is to go-around in the event of a bird strike on approach in most airlines, and is apparently the Boeing suggested response.

During the climb out from the missed approach one of two things happened - either they shut down the wrong engine, or the second engine also took a bird strike and started to fail. Either way, they were left with very limited options. Civil pilots do not learn or practice engine out landings (military pilots of single engine jets do). With little remaining engine power they executed a 'tear drop' turn and got approval to land on the reverse runway - not really an issue since the wind was basically calm. In the circumstances they wouldn't even try to lower the flaps/slats/gear until they were sure they had enough energy to make it back to the runway.

It appears that with a double engine failure the flaps/slats can only be lowered electrically - and this is a slow process. There is a manual undercarriage drop - but that supposedly involves opening a hatch in the cockpit floor and pulling a lever - not something that can be done in a hurry. So by the time they realised they were lined up with the runway, and were 'going to make it' it was already too late to do flaps/slats or gear - and they were too high and fast. It won't surprise me if the accident investigators actually find the gear lever in the down position, and flaps set to some 'medium' position. But with limited hydraulics and electrics, the controls didn't actually respond in time. There is no sign of the air-brakes operating either.

There are no navigation lights or anti-collision strobes visible on the various videos - this suggests a lot of electrical damage. The ADSB traces also stop at or near the (first?) bird strike. We've just got to hope the CVR and ADR continued recording, otherwise I doubt we'll ever know for sure exactly what happened. But at the moment I'm not of the opinion there was any mal intent by the flight deck crew. That's not to say they didn't make mistakes, but given the workload involved in performing an unpracticed 180 teardrop and dead-stick landing after a double engine failure, I'll give them the benefit of the doubt till the accident report says otherwise.

The presence of the berm with the ILS antennas atop is probably what caused the majority of the deaths. However, at most airports if you land more than halfway down the runway and run off the end things are going to end badly for those up front at least, so to my mind that is a secondary consideration. Yes in hindsight in this instance it would have been much better if it weren't there - and I suspect recommendations will follow that such structures should be removed from airport property in line with the under/overruns. But ultimately - if you land long/short then that's the primary problem, and you cannot mitigate every eventuality.
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Doctor Gollum

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Re: Jeju crash.
« Reply #5 on: 30 December 2024, 23:33:38 »

Firstly, not saying that they deliberately acted maliciously, but there are similarities to the two PIA pilots that tried landing an A320 gear up because they hadn't lowered it..

he "airbrakes" are wing spoilers operated by a wow switch once armed. No gear, no weight on wheels activation and no spoilers...

If they had enough hydraulic control to raise the flaps and fly the aircraft for another 5-7 minutes  ;(then they had enough residual pressure in the accumutaor to drop the gear fully extend the flaps and resume the approach.Fundamentally the flaps, and slats, help provide lift at lower speeds and therefore more control.

Single engine landings are obviously trained for. (It goes without saying that if you lose an engine or two, you need to be able to attempt to land at some point).I don't have the specifics for company 737s, (we don't have any), but as a basic rule following engine failure on approach, the priority is to land the aircraft as safely as possible whilst following the QRH. If you have the available thrust for a missed approach and return, then you would potentially do that, but if you can land, and are lined up on finals, that's always your best option. Having had multiple simultaneous toilet smoke alarm on finals, that's exactly what happened next.

Nothing in the last few minutes of available data suggested that they suffered a total power loss although they were faster and higher at the same point as the same aircraft operating the same flight a few days earlier at the point the data ends 154 kts/145kts and 500ft/0ft. Landing hard and fast gear down wouldn't have been optimal, but it might've saved them.

In the audio from the immediate aftermath at least one engine was spooling down.

I wouldn't read too much into the lack of lights in the available video... The resolution isn't great and the frame rate might miss the flashes. And that presumes that they were actually on.

CAP 637 details the requirements of any lighting or navigation fixtures in the UK/Europe. US requirements are similar
https://www.caa.co.uk/our-work/publications/documents/content/cap-637/

There's something about aviation in that part of the world. And when the CCR and FDR get released all will be revealed.
« Last Edit: 30 December 2024, 23:37:28 by Doctor Gollum »
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LC0112G

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Re: Jeju crash.
« Reply #6 on: 31 December 2024, 00:08:56 »

he "airbrakes" are wing spoilers operated by a wow switch once armed. No gear, no weight on wheels activation and no spoilers...

Apparantly not true on a B737NG. And airbrakes work in the air - you must have seen them raised on approach to slow the plane down? No WOW then.

If they had enough hydraulic control to raise the flaps and fly the aircraft for another 5-7 minutes  ;(then they had enough residual pressure in the accumutaor to drop the gear fully extend the flaps and resume the approach.Fundamentally the flaps, and slats, help provide lift at lower speeds and therefore more control.

Except the loss of hydraulics happened AFTER the go around gear/flap/slat clean up. The go-around was initiated before the bird strike. The wheels are already up in the bird strike video, and the flaps appear be almost fully retracted.

Single engine landings are obviously trained for. (It goes without saying that if you lose an engine or two, you need to be able to attempt to land at some point).I don't have the specifics for company 737s, (we don't have any),

Yep - I meant they don't train for dual/all engine failure landings in the civvy world. Single engine failures are routinely practiced in the sim.


but as a basic rule following engine failure on approach, the priority is to land the aircraft as safely as possible whilst following the QRH. If you have the available thrust for a missed approach and return, then you would potentially do that, but if you can land, and are lined up on finals, that's always your best option. Having had multiple simultaneous toilet smoke alarm on finals, that's exactly what happened next.

Suggest you ask the pilot on your next flight. But in the thread on PPRUNE, many pilots are saying SOP for their airline for bird strike on approach is TOGA, declare an emergency and then climb to a safe altitude to assess what still works and what doesn't.

Nothing in the last few minutes of available data suggested that they suffered a total power loss although they were faster and higher at the same point as the same aircraft operating the same flight a few days earlier at the point the data ends 154 kts/145kts and 500ft/0ft. Landing hard and fast gear down wouldn't have been optimal, but it might've saved them.

There is no data after the presumed bird strike. ADSB stopped working.

In the audio from the immediate aftermath at least one engine was spooling down.

Video appears to show some jet efflux from the right/starboard engine - but this is the engine that appears to flame out/ surge in the bird strike video. There is no apparant jet efflux from the left/port engine. I think this is where the dual engine failure/wrong engine shut down theory comes from. A damaged engine can make a lot of noise withour producing much thrust.

I wouldn't read too much into the lack of lights in the available video... The resolution isn't great and the frame rate might miss the flashes. And that presumes that they were actually on.

And if they were not on - why not? Turning nav/collision lights on/off would not be a high priority task in an emergency. The link is with the loss of ADSB however - they may have lost all electrical power, except stuff which is powered by batteries.

CAP 637 details the requirements of any lighting or navigation fixtures in the UK/Europe. US requirements are similar
https://www.caa.co.uk/our-work/publications/documents/content/cap-637/

The berms and ILS stuff were fully compliant with all regulations - more than 250m from the end of the runway overrun.

And when the CCR and FDR get released all will be revealed.

Assuming they continued to record after the (assumed) electrical failures. I've been unable to ascertain if they can run from the batteries, or require AC generator power. And even if they do run, some of the systems that they record may not.
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Doctor Gollum

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Re: Jeju crash.
« Reply #7 on: 31 December 2024, 01:58:48 »

Quote
Apparantly not true on a B737NG. And airbrakes work in the air - you must have seen them raised on approach to slow the plane down? No WOW then.

Flight spoilers and ground spoilers are different control surfaces. And both are split into groups... Half of one wing and half of the other share different hydraulic circuits. Blancolirio did a nice piece on the subject in one of his videos regarding the DHL 757 that crashed in Central America following hydraulic failure.

And don't confuse (not that you would) thrust reversers with spoilers. The reversers CAN be deployed in the air on the NG, something that Ryanair seems to not discourage even though it can have significant consequences.

Quote
Yep - I meant they don't train for dual/all engine failure landings in the civvy world. Single engine failures are routinely practiced in the sim.

That might have changed post US1549. Certainly, Babybus ditching evacuation procedures did, why not flight deck procedures.

Quote
Suggest you ask the pilot on your next flight. But in the thread on PPRUNE, many pilots are saying SOP for their airline for bird strike on approach is TOGA, declare an emergency and then climb to a safe altitude to assess what still works and what doesn't.

I will but not back in until tomorrow. Although I suspect that the suggested SOP is an ideal world guide. And even it it is the case, this crew apparently didn't do that.

Quote
There is no data after the presumed bird strike. ADSB stopped working.

There could be several reasons for this. Electrical failure is one.

Quote
Video appears to show some jet efflux from the right/starboard engine - but this is the engine that appears to flame out/ surge in the bird strike video. There is no apparant jet efflux from the left/port engine. I think this is where the dual engine failure/wrong engine shut down theory comes from. A damaged engine can make a lot of noise withour producing much thrust.

Again the quality of the footage doesn't lend itself to clarity. But with both engines out, from that altitude going straight in would have been safer than going around with limited thrust. Which again suggests that they had at least one functional engine. Without it, doing what they did would have resulted in a similar crash to the Azerbaijani Embraer last week.

Quote
And if they were not on - why not? Turning nav/collision lights on/off would not be a high priority task in an emergency. The link is with the loss of ADSB however - they may have lost all electrical power, except stuff which is powered by batteries.

They should reasonably been on during the flight, but it was daylight and Company SOPs may have allowed for them to be off. The belly anti collision light is between the engines just ahead of the main gear, so wouldn't be visible anyways, and it's not the first aircraft I have seen with a light or two U/S.

Quote
The berms and ILS stuff were fully compliant with all regulations - more than 250m from the end of the runway overrun.

Regulatory compliance suggested that the Titanic had more than enough lifeboats. I suspect that berm will be redesigned.

Quote
Assuming they continued to record after the (assumed) electrical failures. I've been unable to ascertain if they can run from the batteries, or require AC generator power. And even if they do run, some of the systems that they record may not.

They have self contained power sources and should run for a period of time after shut down. And as the aircraft was first delivered to an European airline, it may even still be EASA compliant. (That said, registering an aircraft in Ireland is the aeronautical equivalent of registering a ship in Liberia.)

The biggest issue with retrieving the CVR will be getting into the flight deck.
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Doctor Gollum

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Re: Jeju crash.
« Reply #8 on: 31 December 2024, 02:19:28 »

https://en.wikipedia.org/wiki/Jeju_Air_Flight_2216

Not much time between the Mayday, going around and final crash.

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Re: Jeju crash.
« Reply #9 on: 02 January 2025, 03:54:20 »

Quote
Suggest you ask the pilot on your next flight. But in the thread on PPRUNE, many pilots are saying SOP for their airline for bird strike on approach is TOGA, declare an emergency and then climb to a safe altitude to assess what still works and what doesn't.
To this point, they did what they did, but the consensus from the same starting point would have been to resume the approach and head straight in, or if the situation allowed climb out, fully assess and then coordinate an emergency landing with the airport and aircraft fully prepared.

What actually happened was neither of these things, and hopefully the investigation will go some way to understanding their thought processes.
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Re: Jeju crash.
« Reply #10 on: 28 January 2025, 13:16:42 »

Preliminary report is out.

https://youtu.be/RtGreTnmSDk?si=GJIYOIUFl1wHp-27

Still doesn't explain why they didn't drop straight in, Go around or no go around.
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Re: Jeju crash.
« Reply #11 on: 28 January 2025, 18:50:25 »

Preliminary report is out.

https://youtu.be/RtGreTnmSDk?si=GJIYOIUFl1wHp-27

Still doesn't explain why they didn't drop straight in, Go around or no go around.

Given that they had completely cleaned up the aircraft config I suspect the problem occurred some time into a go-around that might or might not have been related to the ultimate cause of the crash, and they were expecting a lengthy go-around. As such, the aircraft had climbed well above glide slope and in a clean config a landing straight ahead probably wouldn't have been possible at that point.

Sadly the situation clearly deteriorated after that decision and they were left no option but to land clean on the opposing run with the results we all witnessed. :(

Both engines going pop in the initial climb out of a GA must be about the worst scenario that they could have found themselves in. They did well to have got it back to a runway, in my view.

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Doctor Gollum

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Re: Jeju crash.
« Reply #12 on: 28 January 2025, 21:04:55 »

Perhaps, but it was still a questionable decision with the runway lined up at that point.

If they hadn't hit the wall it would have ended up in the sea.
« Last Edit: 28 January 2025, 21:07:13 by Doctor Gollum »
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