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

[Phillip9]

5 minutes ago, richard_smith237 said:

Backup electric hydraulic systems failed (no idea why).

 

If both engines are out, the backup electric hydraulics won't work immediately because the main electrical will be out.  They would need to deploy the APU (back up generator) first.  They probably didn't have time for that or were preoccupied trying to restart an engine.

[richard_smith237]

19 minutes ago, Phillip9 said:

24 minutes ago, richard_smith237 said:

Backup electric hydraulic systems failed (no idea why).

 

If both engines are out, the backup electric hydraulics won't work immediately because the main electrical will be out.  They would need to deploy the APU (back up generator) first.  They probably didn't have time for that or were preoccupied trying to restart an engine.

 

I've read that the back-up electric-motor hydraulic pumps are (theoretically) available instantaneously. 

Firstly there is residual hydraulic pressure - After engine failure it doesn't just 'bleed off'.

The back-up electric-motor hydraulic pumps work off the battery the response is instant. 
This bridges the gap / time it takes to engage the APU (which as you mentioned takes a bit of time - its 60-90 seconds)

 

This is why I have questioned If there was a possible pilot error in not switching over to back-up power - i.e. pre-occupied with trying to restart the engines (as you mentioned), or just using their strength to control the air-craft manually without the assistance of hydraulics.

 

 

 

On 12/31/2024 at 11:04 AM, richard_smith237 said:

I'm not so sure about that.

 

Apparently, on the 737-800 the transition / switchover to the electric-driven pumps is effectively instantaneous if the electric pumps are already activated. There may be a brief delay (a few seconds) as the system stabilises and pressure builds up if the pumps were not initially active.

 

If the electric-motor hydraulic pumps were not already turned on, the pilots must manually activate them using switches in the cockpit. This process takes only a few seconds, as the pumps can be activated quickly - IF the pilot recognises the issue. 

 

Thus: either there was a catastrophic failure of backup  electric-motor driven hydraulic systems, or there was pilot error (I hesitate to say that, but consideration must be given to possible fallibility).

 

 

[Moonlover]

1 hour ago, richard_smith237 said:

1 hour ago, Phillip9 said:

This video shows it at 49s.  It was taken around 5nm out, well before the bird strike.

 

 

I'm guessing they aborted the initial landing and raised the gear before the bird strike.  They were warned about birds, and maybe saw lots of them in advance and aborted to try and avoid them.

 

1 hour ago, richard_smith237 said:

 

 

That makes a sense...  thus a possible: 

 

1) Bird strike warning

2) observed significant number of birds ahead.

3) Decision made to abort landing and 'go around' to approach north.

4) Encountered bird strike, one engine out.

5) Did the pilot shut down the correct engine (potential pilot error ?)

6) Hydraulic loss (no - Flaps and Slats / no landing gear)

7) Too late to engage landing gear manually

😎 Backup electric hydraulic systems failed (no idea why).

9) Landing north to South at speed (no flaps / slats / landing gear)

10) Ground effected resulted in touch-down 1200m down the runway (1600m reaming runway)

11) No reverse thrust (engines shut down ?) Air-craft will not arrest

12) Earth Berm topped with Concrete Raft for ALS hit at speed, aircraft explodes.

 

 

This of course is pure speculation - but given what has been reported and discussion here, its a laymans idea of possible sequence of events.

 

 

**no doubt some bright spark will come along with a comment on this discussion and criticism AN sleuths who thing we can solve the mystery instead of waiting for the results of the official investigation, and in doing so will completely miss the whole point of having an informal discussion on a forum such as this (just getting out ahead of such likely moronic comments). 

 

 

 

 

I don't think that video shows the bird strike. @richard_smith237 the calculation you posted earlier, which I've no reason to dispute,  would indicate that the bird strike took place whilst the aircraft was still over water. However, the video clip shows an aircraft over land with its gear retracted. It's only short clip and then it disappears from view , occluded by a concrete structure. (in the sea?) More likely the plume we see from the engine as it passes over is the result of a compressor stall, or similar resulting from bird ingestion.

 

I'm guessing that the pilot would have retracted the landing gear because he now had reduced thrust from the damaged engine(s) and wanted to 'clean up' in order to maintain height. A pilot's number one priority in such circumstances.

 

So why go for a landing on 19, rather than go around and line up on 01 again? To go around again would mean flying back out over the sea and both you and I agree, much to someone's chagrin, that ditching into water is the very last option. Going for 19 kept him close to the runway and overland.

 

So back to the video clip, it was likely shot as the aircraft passed overhead on final and fated flight north.

[richard_smith237]

12 minutes ago, Moonlover said:

 

 

I don't think that video shows the bird strike. @richard_smith237 the calculation you posted earlier, which I've no reason to dispute,  would indicate that the bird strike took place whilst the aircraft was still over water. However, the video clip shows an aircraft over land with its gear retracted. It's only short clip and then it disappears from view , occluded by a concrete structure. (in the sea?) More likely the plume we see from the engine as it passes over is the result of a compressor stall, or similar resulting from bird ingestion.

 

I'm guessing that the pilot would have retracted the landing gear because he now had reduced thrust from the damaged engine(s) and wanted to 'clean up' in order to maintain height. A pilot's number one priority in such circumstances.

 

Good point, and that all makes sense. 

 

12 minutes ago, Moonlover said:

 

So why go for a landing on 19, rather than go around and line up on 01 again? To go around again would mean flying back out over the sea and both you and I agree, much to someone's chagrin, that ditching into water is the very last option. Going for 19 kept him close to the runway and overland.

 

So back to the video clip, it was likely shot as the aircraft passed overhead on final and fated flight north.

 

Again, perfectly valid points....  I initially assumed the 'bird strike video' was taken on initial approach (South to North onto Runway 01), however, it does make more sense that the video was taken on a secondary approach (North to South onto Runway 19)

[rabas]

It's easy to show the bird strike occurred early during the initial approach from the south, and that the final landing was from the north.  All you need is time of day and the sun's direction. The plane's right (bird strike) side is brightly lit by the morning sun as it approaches from the south and the sea. The later crash video shows the plane's right side in deep shadow and even sun reflections off the top of the fuselage. 

 

Further, a newer video shows the plane's initial approach even earlier revealing a series of right engine explosive bursts. Even before that, there appears to be a smoke trail suggesting that bird strikes occurred even earlier. 

 

Earlier approach video link here.  Note, the video is shown at various speeds, the last is clearest. 

 

Approaching from the south, sun lit from the East.

 

Landing from the mountainous north lit on the plane's left by the morning sun. 

 

 

[Harsh Jones]

A pilots take which is similar to what I have been saying all along

 

Surely I cannot be the only professional aviator wading through this thread thinking that the whole "berm debate" is...superfluous? In what world does landing unconfigured more than halfway down a runway carrying a tremendous amount of energy NOT have a bad outcome?

While airport design of course has a role to play in overall safety, ultimately it is OUR job (speaking to other actual pilots, please, not simmers and enthusiasts) to keep the operation within the lines. This wasn't marginally outside those lines.

In that light the endless ruminating about The Berm is pointless when I'd wager every actual working pilot is quietly mulling how they never want to perform this "landing", and wanting to know what combination of technical and human factors led to the aircraft being in the aforementioned state.

The placement of the obstacle was tragically unfortunate but the allocation of discussion to it is astonishingly misplaced.

[richard_smith237]

1 hour ago, Harsh Jones said:

A pilots take which is similar to what I have been saying all along

 

Surely I cannot be the only professional aviator wading through this thread thinking that the whole "berm debate" is...superfluous? In what world does landing unconfigured more than halfway down a runway carrying a tremendous amount of energy NOT have a bad outcome?

While airport design of course has a role to play in overall safety, ultimately it is OUR job (speaking to other actual pilots, please, not simmers and enthusiasts) to keep the operation within the lines. This wasn't marginally outside those lines.

In that light the endless ruminating about The Berm is pointless when I'd wager every actual working pilot is quietly mulling how they never want to perform this "landing", and wanting to know what combination of technical and human factors led to the aircraft being in the aforementioned state.

The placement of the obstacle was tragically unfortunate but the allocation of discussion to it is astonishingly misplaced.

 

I kind of agree with that.

 

A significant amount of the social media discussion involves the berm-wall - I think its universally agreed that this crash would not have been so deadly had that berm-wall not been there.

 

But, there were also a series of cascading events which led the the air-craft landing without flaps & slats and without landing gear after suffering a bird strike and losing one possibly two engines - I agree withe pilots comment on this point, everyone discussing this wants to know.

 

 

However, I think the pilot's comments are also flawed when he questions "in what world.... "   because the answer to that is obvious... 'in the world of catastrophic failure and emergency landings'....  i.e. in a world where the aircraft can no longer remain airborne !!!

 

Additionally... When the pilot mentions "its their job to keep the operation within the lines"... the very nature of an emergency is when the operation steps beyond the bounds of those lines - again his comment seems to miss this point.

 

 

[Harsh Jones]

I am unsure why they were so quick to do a go-around after the bird strike. 

 

An aircraft is hit by birds while on final approach to land - should the pilot continue the approach or initiate a go around/missed approach?

 

Having encountered birds, the question to be answered is "what is the damage to the aircraft and what effect will this have on the safe conduct of the flight?".

The full extent of any damage, to the engines and/or the control surfaces and landing gear, may not be apparent until applying power, configuring, or manoeuvring the aircraft. It might therefore be the case that, if a go-around is initiated, the pilots rapidly find themselves in a situation where the runway is disappearing beneath them but the aircraft cannot safely fly a missed approach.

 

Therefore, in the above scenario, it is advisable to continue the approach and land.

[Phillip9]

15 hours ago, richard_smith237 said:

The back-up electric-motor hydraulic pumps work off the battery the response is instant. 
This bridges the gap / time it takes to engage the APU (which as you mentioned takes a bit of time - its 60-90 seconds)

 

I read the opposite, but I'm not 100% sure.  The aircraft external lights were off when landing, so we know they still had electric failure during landing, so I think it is likely that any backup electric hydraulic pump was also not working.

[Phillip9]

3 hours ago, Harsh Jones said:

I am unsure why they were so quick to do a go-around after the bird strike. 

 

An aircraft is hit by birds while on final approach to land - should the pilot continue the approach or initiate a go around/missed approach?

 

Having encountered birds, the question to be answered is "what is the damage to the aircraft and what effect will this have on the safe conduct of the flight?".

The full extent of any damage, to the engines and/or the control surfaces and landing gear, may not be apparent until applying power, configuring, or manoeuvring the aircraft. It might therefore be the case that, if a go-around is initiated, the pilots rapidly find themselves in a situation where the runway is disappearing beneath them but the aircraft cannot safely fly a missed approach.

 

Therefore, in the above scenario, it is advisable to continue the approach and land.

 

Really tough to criticize the go around decision until we know the details of when the go around was called (before or after the first bird strike?) and what the pilots saw between them and the runway.  Reports are that lots and lots of birds were in the area.  What should pilots do if they have one bird strike but then see a flock of hundreds more large birds between them and the runway?

[Moonlover]

2 hours ago, Phillip9 said:

 

Really tough to criticize the go around decision until we know the details of when the go around was called (before or after the first bird strike?) and what the pilots saw between them and the runway.  Reports are that lots and lots of birds were in the area.  What should pilots do if they have one bird strike but then see a flock of hundreds more large birds between them and the runway?

But we do know when the pilot declared MAYDAY. It was after the bird strike. From the @Georgealbert's post on page 7

 

8:57L: Air traffic control broadcasts “caution - bird activity” advisory.

8:59L: Flight 7C-2216 pilot reports bird strike, declares emergency “Mayday Mayday Mayday” and “Bird strike, bird strike, go-around.”

9:00L: Flight 7C2216 initiates a go-around and requests authorisation to land on runway 19, which is by approach from the opposite end of the airport’s single runway.

 

What we don't know is whether the pilot had seen the birds and taken any evasive action to avoid them. He was close to touchdown, so any significant diversion from the glideslope could have put them in a position whereby continuing to land would have been inadvisable. His actions, calling for a go-around, would suggest that's the case.

 

This should come out of course once the flight recorders have been decoded.

[Moonlover]

13 hours ago, rabas said:

It's easy to show the bird strike occurred early during the initial approach from the south, and that the final landing was from the north.  All you need is time of day and the sun's direction. The plane's right (bird strike) side is brightly lit by the morning sun as it approaches from the south and the sea. The later crash video shows the plane's right side in deep shadow and even sun reflections off the top of the fuselage. 

 

Further, a newer video shows the plane's initial approach even earlier revealing a series of right engine explosive bursts. Even before that, there appears to be a smoke trail suggesting that bird strikes occurred even earlier. 

 

Earlier approach video link here.  Note, the video is shown at various speeds, the last is clearest. 

 

Approaching from the south, sun lit from the East.

 

Landing from the mountainous north lit on the plane's left by the morning sun. 

 

 

 

Well deduced. I think the top photo, showing the plume of smoke, or whatever was taken as they were heading north, parallel to the runway. There's a concrete structure which just shows up in the top left corner. So they were obviously over land at the time.

 

And in the video you even see the birds scattering at bottom left!

[richard_smith237]

7 hours ago, Phillip9 said:

I read the opposite, but I'm not 100% sure.  The aircraft external lights were off when landing, so we know they still had electric failure during landing, so I think it is likely that any backup electric hydraulic pump was also not working.

 

Yep...  that makes sense.

 

The bird strike caused the initial engine failure (and thus main hydraulic failure).

The backup electrical system also may have encountered a failure.

 

Thus: this was also failure of redundancy.

 

[Harsh Jones]

On 1/3/2025 at 1:54 AM, richard_smith237 said:

 

Yep...  that makes sense.

 

The bird strike caused the initial engine failure (and thus main hydraulic failure).

The backup electrical system also may have encountered a failure.

 

Thus: this was also failure of redundancy.

 

There's no way that this happened. It just isn't possible. Anyone who's taken an interest in this topic and has watched some crash investigations knows that this isn't what happened. I wouldn't even fly if  I thought this was remotely possible. Perfectly flyable aircraft have been crashed many times due to mistakes and unfortunate situations in the cockpit. South Korean Asiana Air 214 being a recent example. 3 captains and one first officer and they crashed an aircraft with nothing wrong with it.

 

The investigation by the U.S. National Transportation Safety Board (NTSB) concluded that the (Asiana Air 214) accident was caused by the flight crew's mismanagement of the airplane's final approach. Deficiencies in Boeing's documentation of complex flight control systems and in Asiana Airlines' pilot training were also cited as contributory factors.^[

 

And these pilots did not have a perfectly flyable aircraft. They had one engine out. Which is still a flyable aircraft but it just introduced a lot of variance for them. These pilots took off at literally 2 am. 2 am is the most out of sync time to be awake. Pilot error is more than likely the cause of the crash. 

[Harsh Jones]

A former air-force pilot and current commercial pilots take. At 11:50 he says "have you run the numbers?". He meant that literally. You have to run the numbers. 

 

 

[Phillip9]

18 minutes ago, Harsh Jones said:

A former air-force pilot and current commercial pilots take. At 11:50 he says "have you run the numbers?". He meant that literally. You have to run the numbers. 

 

The really funny thing is that he repeatedly says that he thinks they didn't lower the gear and flaps because he thinks hydraulics failed.  

 

And in your previous post you just said "There's no way that this happened. It just isn't possible."  in response to our comments stating we thought hydraulics failed.

[Harsh Jones]

20 minutes ago, Phillip9 said:

 

The really funny thing is that he repeatedly says that he thinks they didn't lower the gear and flaps because he thinks hydraulics failed.  

 

And in your previous post you just said "There's no way that this happened. It just isn't possible."  in response to our comments stating we thought hydraulics failed.

He doesn't say that at all. What are you talking about ? He says that the primary feed for the landing gear happens to be on the same side as the engine that went out. He does not say that this means they couldn't get the gear down. Both sides are connected all the time. Both sides are redundant to each other 

 

At 23:30 he says it was quite "terrible airmanship and terrible judgment and there is NO reason to rush like this." And he says the 737 "flies beautifully" on one engine 

 

Then he follows it up by saying there's 20,000 bird strikes a year in North America alone.

 

And then at 26:50 he says "all of this was apparently caused by very very poor decision making by the pilots"

 

And you think a bird strike basically took a plane. Nonsense.

 

 

[Phillip9]

1 hour ago, Harsh Jones said:

He doesn't say that at all. What are you talking about ? He says that the primary feed for the landing gear happens to be on the same side as the engine that went out. He does not say that this means they couldn't get the gear down

 

"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."

 

[richard_smith237]

3 hours ago, Harsh Jones said:

There's no way that this happened. It just isn't possible.

 

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.... 

 

 

36 minutes ago, 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."

 

This...      

 

 

 

 

[richard_smith237]

3 hours ago, Harsh Jones said:

I wouldn't even fly if  I thought this was remotely possible.

 

Enjoy the long boat rides...