Jeju Air Flight from Bangkok Skids Off Runway at Muan Airport, 28 Dead

[Harsh Jones]

On 1/4/2025 at 11:12 PM, Phillip9 said:

 

"You need hydraulic pressure to bring that gear down or up.  So obviously the engine the left engine was running when they brought the gear and flaps up but then when they came in to land it was not running."

 

He didn't mean that losing that engine means losing gear hydraulic pressure. That would mean there's no redundancy which is clearly untrue. Even with both engines and the RaT out , there's nitrogen charged accumulators.

 

Im not trying to throw the pilots under the bus. I'm just stating the obvious. Things go wrong with aircraft all the time. And crash landing is never on the checklist. 

[Harsh Jones]

On 1/4/2025 at 11:48 PM, richard_smith237 said:

 

Its clear from many of your comments that you have no idea whats possible and what isn't....   you keep contradicting yourself.

 

All of the assumptions you are making are based on the 'theory' that one of the engines remained operational. 

 

You will not accept the possibility that both engines had failed, it was this failure that led to no flaps, no slats, no landing gear, electrical failure (as indicated by no landing lights - possibly), high landing at speed, ground effect, a late touchdown....

I can accept that all of those things failed. And even with that , crash landing the aircraft is not the right course of action. Because that's what they did. It was a crash landing. 

 

I've watched hundreds of hours of flight crash investigations. I can tell who the commenters are who've barely watched any.

 

It is almost comical that you think that a basic technical problem or even 2 or 3 serious technical problems would be grounds to crash land an aircraft. It doesn't work like that at all. 

 

Hey, no hydraulics. gotta crash land. Engine out , gotta crash land. 2 engines out , gotta crash land. Nothing short of uncontrolled fire in the flight deck is a reason to crash land. Things go wrong with aircraft all the time. And the reason flying is safe is because you almost never have to crash land. 

 

 

[Tug]

1 hour ago, Harsh Jones said:

I can accept that all of those things failed. And even with that , crash landing the aircraft is not the right course of action. Because that's what they did. It was a crash landing. 

 

I've watched hundreds of hours of flight crash investigations. I can tell who the commenters are who've barely watched any.

 

It is almost comical that you think that a basic technical problem or even 2 or 3 serious technical problems would be grounds to crash land an aircraft. It doesn't work like that at all. 

 

Hey, no hydraulics. gotta crash land. Engine out , gotta crash land. 2 engines out , gotta crash land. Nothing short of uncontrolled fire in the flight deck is a reason to crash land. Things go wrong with aircraft all the time. And the reason flying is safe is because you almost never have to crash land. 

 

 

Both engines out 500 feet of altitude having allready overflown the runway…….you are going to land no doubt about it.Personally I find it remarkable they got her turned around and made the runway it’s to bad they landed long and floated in ground effect.they had 10s of seconds to set up and land.Its remarkable they made the runway and made a perfect no flaps gear up landing.we Will find out in due time the status of the engines and systems the rest is just speculation.it’s tragic that the instrumentation at the end of the runway was built on such a  substantial foundation otherwise I’m sure there would have been more survivors.my condolences to the bereaved oh and they have reported finding bird remains in an engine they didn’t say which one or both.

[Phillip9]

3 hours ago, Harsh Jones said:

On 1/5/2025 at 1:12 PM, Phillip9 said:

You need hydraulic pressure to bring that gear down or up.  So obviously the engine the left engine was running when they brought the gear and flaps up but then when they came in to land it was not running."

 

Expand  

He didn't mean that losing that engine means losing gear hydraulic pressure. That would mean there's no redundancy which is clearly untrue. Even with both engines and the RaT out , there's nitrogen charged accumulators.

 

Then why was it obvious to him that the left engine was running when they brought the gear up after the go around?  

 

The 737 doesn't have accumlators for hydrolics or a RAT.  It has an APU, but it's not a RAT.

[rabas]

4 hours ago, Phillip9 said:

 

Then why was it obvious to him that the left engine was running when they brought the gear up after the go around?  

 

The 737 doesn't have accumlators for hydrolics or a RAT.  It has an APU, but it's not a RAT.

 

Other than his 25 years of experience, the answer may be that landing gears are easy to drop but hard to pull back up. 737-800 landing gears can be dropped even manually but pulling them up requires hydraulic system A (of three), which is primarily powered by left engine 1. 

 

737-800s have 3 hydraulic systems, A, B, and Backup. A and B are not symmetrical. A is primary and primarily (sorry) powered off left engine 1. B is powered off right engine 2. See this detailed functional description of 737-800's hydraulic systems:

 

http://737exam.com/pdf/BOEING 737-13 Hydraulics.pdf

 

So, if they retracted the landing gear to go around, then engine 1 was likely running.

 

Note this is subtle. Systems A and B have partial cross backup capability so that on engine 1 failure during takeoff, system B can assist system A (on dead engine 1) to pull the landing gear up. But in the current case, engine 2 is assumed toast due to the bird strike. 

 

So if engine 1 was running before the go around, what happened later? Why no landing gear? 

 

Point 2

 

If  hydraulic systems A and B both fail, the backup system powers minimal systems seemingly required for a worst case landing. These are:

 

- Engine 1 & 2 thrust reversers  <=== (observed during landing ?)
- Standby rudder
- Leading edge flaps & slats ( extension only )
- Standby yaw damper ( loss of system A & B

 

[Phillip9]

3 hours ago, rabas said:

Other than his 25 years of experience, the answer may be that landing gears are easy to drop but hard to pull back up. 737-800 landing gears can be dropped even manually but pulling them up requires hydraulic system A (of three), which is primarily powered by left engine 1. 

I know that.  I was responding to the other poster who keeps claiming that pilot does not say there was a hydraulic failure.  The pilot in the video very clearly says he thinks there was a hydraulic failure and that was my only point.

 

 

3 hours ago, rabas said:

If  hydraulic systems A and B both fail, the backup system powers minimal systems seemingly required for a worst case landing. These are:

The backup hydraulic pumps are electric and the aircraft clearly had an electrical failure since it stopped transmitting position data and the external lights were off during landing, so there is no way that the backup hydraulic system was working.

 

[richard_smith237]

11 hours ago, Harsh Jones said:

I can accept that all of those things failed. And even with that , crash landing the aircraft is not the right course of action. Because that's what they did. It was a crash landing. 

 

Its a crash-landing !!!... You are presenting your agreement as if they have a choice which shows a profound misunderstanding.

 

11 hours ago, Harsh Jones said:

I've watched hundreds of hours of flight crash investigations. I can tell who the commenters are who've barely watched any.

 

I'd expect even an arm-chair expert to draw more logical conclusions than you have managed - some of your comments are outright odd.

 

11 hours ago, Harsh Jones said:

It is almost comical that you think that a basic technical problem or even 2 or 3 serious technical problems would be grounds to crash land an aircraft. It doesn't work like that at all. 

 

What is comical is that you fail to grasp the concept of cascading failure.

 

 

11 hours ago, Harsh Jones said:

Hey, no hydraulics. gotta crash land. Engine out , gotta crash land. 2 engines out , gotta crash land. Nothing short of uncontrolled fire in the flight deck is a reason to crash land.

 

Astonishing - You seem serious enough with your comments, but I'm struggling not to wonder if you are not trolling.

 

You write as if the Pilot had options and 'chose to crash land a plane' instead of 'going around again' when its blatantly clear, there were no other options than get the plane down. 

 

You've previously mentioned landing on the water, which is just ridiculous, highlighting that you have not learned a thing from the hundreds of hours of 'air-crash' investigations you watched.

 

11 hours ago, Harsh Jones said:

Things go wrong with aircraft all the time. And the reason flying is safe is because you almost never have to crash land. 

 

So, they crash landed because the experienced pilot 'wanted to' ???  

 

[richard_smith237]

14 minutes ago, Phillip9 said:

I know that.  I was responding to the other poster who keeps claiming that pilot does not say there was a hydraulic failure.  The pilot in the video very clearly says he thinks there was a hydraulic failure and that was my only point.

 

 

The backup hydraulic pumps are electric and the aircraft clearly had an electrical failure since it stopped transmitting position data and the external lights were off during landing, so there is no way that the backup hydraulic system was working.

 

 

Its possible there was a cascading failure whereby Hydraulic power was available when the Pilots decided to make the 'go-around'... However, deteriorating systems, possibly the loss of the second engine necessitated the 'north to south'l anding without power and minimal hydraulics (but no flaps / slats / landing gear).

[nauseus]

Looks like the full truth might take longer to emerge than expected:

 

https://www.investing.com/news/stock-market-news/south-korea-jeju-air-jet-blackboxes-stopped-recording-4-minutes-before-crash-ministry-says-3807951

[Phillip9]

2 minutes ago, nauseus said:

Looks like the full truth might take longer to emerge than expected:

 

https://www.investing.com/news/stock-market-news/south-korea-jeju-air-jet-blackboxes-stopped-recording-4-minutes-before-crash-ministry-says-3807951

 

This was already expected.  The flight data recorder and cockpit voice recorder on that aircraft will stop working if main electrical power fails.  We've already known that the main power failed because the aircraft stopped transmitting position data shortly after the mayday, and the aircraft external lights were off during landing.

 

They should at least get the voice recordings and flight data before engines failed.

[nauseus]

2 hours ago, Phillip9 said:

 

This was already expected.  The flight data recorder and cockpit voice recorder on that aircraft will stop working if main electrical power fails.  We've already known that the main power failed because the aircraft stopped transmitting position data shortly after the mayday, and the aircraft external lights were off during landing.

 

They should at least get the voice recordings and flight data before engines failed.

 

I didn't see any "expectations" published or posted about this problem but never mind.

 

Both recorders specifically require power from at least one active engine to operate normally, unless they have a RIPS (extra battery DC supply circuit) system, as in the newer 737 Max versions. This indicates that it is likely that both jets lost significant thrust before the landing attempt.

[Phillip9]

35 minutes ago, nauseus said:

This indicates that it is likely that both jets lost significant thrust before the landing attempt.

 

I agree, this seems to be one more indication that both engines failed, or at least lost most thrust before landing.  

 

I think the main question now is did both engines fail due to bird strikes, or was only one damaged by a bird, and the other one was shut down by mistake.  Hopefully the data recorders were running long enough to solve that mystery.

[Harsh Jones]

 

Comments: I’m a mechanic for many years on 737-800. There is no reason they will stop recording, They work on battery power also The APU is a one flick of the finger start that takes around 30 seconds. No idea unless circuit breakers are pulled. This is very strange.

 

That was always going to happen, the loss of face to have such a monumental cock up laid bare for the world to see would’ve been unforgivable.

 

[Harsh Jones]

Now some ppl are saying that the dual engine failure caused all power to be lost. This of course , is nonsense. There is 2 separate battery systems in the aircraft that can run everything in the event that both engines are out and even if the APU is out. Wind milling engines also still can generate power. 

 

There's also some nonsense in the news about how this aircraft didn't have a data box battery. This is irrelevant. Those batteries are for when an aircraft breaks up and is sitting at the bottom of the ocean. It runs the pinger so the box can be found. It is not there to have power backup for when engines are out. 

 

It amazes me how many people think an aircraft will have no electrical power bevause the engines broke down. 

[Harsh Jones]

10 hours ago, Phillip9 said:

 

This was already expected.  The flight data recorder and cockpit voice recorder on that aircraft will stop working if main electrical power fails.  We've already known that the main power failed because the aircraft stopped transmitting position data shortly after the mayday, and the aircraft external lights were off during landing.

 

They should at least get the voice recordings and flight data before engines failed.

This is a compete fantasy. There is 2 main battery systems to run everything in the event that both engines , APU and RAT fail. Plus a wind milling engine can generate power. 

 

How could you possibly think that a 2 engine failure will lead to no electical power instantaneously? 

 

Even your car has electrical power after it runs out of gas 

[Harsh Jones]

8 hours ago, nauseus said:

 

I didn't see any "expectations" published or posted about this problem but never mind.

 

Both recorders specifically require power from at least one active engine to operate normally, unless they have a RIPS (extra battery DC supply circuit) system, as in the newer 737 Max versions. This indicates that it is likely that both jets lost significant thrust before the landing attempt.

That is incorrect 

 

The 737NG has two 24 volt nickel–cadmium batteries, one main and one auxiliary, located in the electronics compartment. The auxiliary battery operates in parallel with the main battery when powering the standby system. The batteries can power all systems for 60 minutes.

 

A dual engine failure does not lead to instantaneous loss of electrical power. 

 

 

• The B737 flight controls are hydraulically powered.
• There are three hydraulic systems: System A, System B, and Standby. Only one main system (A or B) is required for hydraulically flying the aircraft, during normal operation they are both operational.
• The two main hydraulic systems have an Engine Driven Pump (EDP), which can continue delivering hydraulic pressure when the associated engine is windmilling. All three hydraulic systems are also powered by their own Electric Motor Driven Pump (EMDP).
• In case of dual engine failure the APU can power the electrical systems for the EMDPs, still delivering full hydraulic power.
• If the fuel has run out and the APU cannot operate, two batteries provide at least 60 minutes of backup power for the electrical systems. The EDMPs can be powered in this stage, however they provide a high load.

 

[Phillip9]

19 minutes ago, Harsh Jones said:

This is a compete fantasy. There is 2 main battery systems to run everything in the event that both engines , APU and RAT fail.

 

The 737 doesn't even have a RAT.  You keep making that part up over and over and over again. 

 

I won't respond to you any further because you are clearly just a troll and not worth my time.

[Harsh Jones]

1 hour ago, Phillip9 said:

 

The 737 doesn't even have a RAT.  You keep making that part up over and over and over again. 

 

I won't respond to you any further because you are clearly just a troll and not worth my time.

The engines are the RAT. The engines generate power when they windmill. 

[Harsh Jones]

13 hours ago, Phillip9 said:

 

This was already expected.  The flight data recorder and cockpit voice recorder on that aircraft will stop working if main electrical power fails.  We've already known that the main power failed because the aircraft stopped transmitting position data shortly after the mayday, and the aircraft external lights were off during landing.

 

They should at least get the voice recordings and flight data before engines failed.

 

The 737 has 60 minutes of backup electrical power, supplied by 2 main system batteries. The the event that all fuel is lost, for both engines and the APU, there is an hours worth of electrical power to run all the electrical systems. 

 

The battery people are talking about in the news is something separate when the aircraft breaks up or is at the bottom of the ocean. That battery is there to run the pinger and is not relevant to an intact aircraft.