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

[Moonlover]

2 hours ago, Moonlover said:

They did not lose hydraulics. The flight surfaces were still working.

Oh and one more thing I forgot to mention @Harsh Jones.

 

'The ailerons, spoilers, rudder, and elevators are powered by the A and B hydraulic systems. If both hydraulic systems A and B fail, control of the ailerons and elevators reverts to manual', 

 

Boeing still, very wisely, still install control rods from the cockpit to the control surfaces on the 737.

 

https://www.aviationhunt.com/boeing-737-flight-control-surfaces/

[Phillip9]

37 minutes ago, Elkski said:

How do we know electrical failure?  

 

The aircraft stopped transmitting location data shortly after they declared an emergency.  

[Phillip9]

1 hour ago, nauseus said:

1 hour ago, Phillip9 said:

Watch all the videos posted on this thread already.  All this info is in them.

 

You mean your list of guesswork?

 

Most of those are rather obvious and well know.  If you have some that aren't clear to you, ask and I can show you the particular link.

[Neeranam]

21 minutes ago, In Full Agreement said:

 

 

I wonder why a sand pit isn't used at the end of the runway to stop the plane as is done with runaway trucks?

 

 

I was thinking the same or large balloons. 

[Harsh Jones]

2 hours ago, Moonlover said:

There is a contradiction in your logic. Ponder this.

 

If he had one good engine, why didn't the pilot continue with the normal go around and make a fresh approach, deploying flaps, spoilers and landing gear? As you yourself point out he could have done that with ease on one engine.

 

Instead he chose to make a very hasty turn back and landed without flaps, spoilers or landing gear. Now that, in my mind adds up to double engine failure. Think back to the so called 'Miracle on the Hudson'. That event took 3 1/2 minutes unfold. It was a similar time frame for this incident as well.

 

 

 

Because even with a double engine failure, he could have landed with flaps, spoilers and landing gear. Even with 2 engines gone, they still have nitrogen accumulator backups that pressurize the hydraulics. Plus some of the flight surfaces also have electric power backup.

 

On the Hudson, Sully had hydraulics. His only concern was air speed and lack of it. The recent Russian airliner that landed in a corn field after both engines were hit by birds, also had full hydraulics. 

 

[Harsh Jones]

1 hour ago, Phillip9 said:

 

Note also that gear hydraulics are run by the left engine (the one that appears to be completely off), and the flaps and spoiler hydraulics are run by the right engine.  Something else pointing to a double engine failure.

 

All airliners have hydraulic nitrogen accumulators that store pressurized fluid and provide backup power for various systems. Both engines could fall off mid flight and they would have hydraulics for hours. 

 

Hydraulic systems: Accumulators operate the main hydraulic system and the emergency system. 

 

Landing gear: Accumulators provide backup power for the landing gear. 

 

Brakes: Accumulators provide backup power for the brakes. 

 

Emergency applications: Accumulators provide backup power for emergency applications. 

 

 

 

[ronnie50]

As someone already pointed out and something I mentioned, way back when, the plane isn't really skidding on its belly. It's clear that most of the plane is above the runway. The forward motion, and resistance to it, is from the massive engines skidding along the runway. Only the back of the plane near the tail is skidding along. So not enough of the plane (belly) was actually touching the runway to help slow it down. Anyway, just one more observation. Boeing changed the engine design on its newer 737 versions at least 10+ years ago, making them bigger, but more fuel efficient. I wonder how many previous examples of a belly landing with a 737-800 are similar and what were the outcomes. 

[Harsh Jones]

One thing that could have disoriented and caused the pilots to drop the aircraft was smoke in the cockpit. There is a recent report about bird struck engines causing smoke in the cockpit for the 737 Max with the CFM engines. This wasn't a Max but the engines were CFM. Maybe this is a possibility even though it wasn't a Max. 

 

But you can see light through the windscreen in the video so I am a bit skeptical of this theory 

 

https://www.cnn.com/2024/06/19/business/smoke-cabin-boeing-737-max-bird-strike/index.html

[Phillip9]

1 hour ago, Harsh Jones said:

Because even with a double engine failure, he could have landed with flaps, spoilers and landing gear. Even with 2 engines gone, they still have nitrogen accumulator backups that pressurize the hydraulics. Plus some of the flight surfaces also have electric power backup.

 

On the Hudson, Sully had hydraulics. His only concern was air speed and lack of it. The recent Russian airliner that landed in a corn field after both engines were hit by birds, also had full hydraulics. 

 

On a 737 the only accumulator is for braking.  The engines normally produce the hydraulic pressure.  If both engines are out, you will immediately have no hydraulics and no electronics.  The 737 can be flown with no hydraulics because it has back up manual control cables.

 

There is a back up electric generator, but that takes time to deploy.  That will give you electronics.  Then there are back up electric hydraulic pumps that will restore hydraulics.  That's what Sully did.  

 

The Jeju plane was so low, that they likely did not have time to get through these steps to restore hydraulics and then lower the gear and flaps.

 

 

 

[Moonlover]

1 hour ago, Harsh Jones said:

 

Because even with a double engine failure, he could have landed with flaps, spoilers and landing gear. Even with 2 engines gone, they still have nitrogen accumulator backups that pressurize the hydraulics. Plus some of the flight surfaces also have electric power backup.

 

On the Hudson, Sully had hydraulics. His only concern was air speed and lack of it. The recent Russian airliner that landed in a corn field after both engines were hit by birds, also had full hydraulics. 

 

So I'll assume from this post that you are now conceding that there is a possibility that there was a double engine failure.

 

Personally, I am convinced that it was a double engine failure. And that conviction comes not from all the technical arguments, but from the pilot's actions, especially his radio transmission. If the aircraft had suffered a single engine failure, he would have made a 'PAN-PAN' call and followed air traffics instructions to make a second landing attempt. 

 

But he didn't. He declared 'MAYDAY-MAYDAY'. That screams at me a double engine failure. 'Get me on ground NOW!'

 

I shall await, with interest, the results of the enquiry.

[nauseus]

32 minutes ago, Phillip9 said:

 

On a 737 the only accumulator is for braking.  The engines normally produce the hydraulic pressure.  If both engines are out, you will immediately have no hydraulics and no electronics.  The 737 can be flown with no hydraulics because it has back up manual control cables.

 

There is a back up electric generator, but that takes time to deploy.  That will give you electronics.  Then there are back up electric hydraulic pumps that will restore hydraulics.  That's what Sully did.  

 

The Jeju plane was so low, that they likely did not have time to get through these steps to restore hydraulics and then lower the gear and flaps.

 

 

 

 

Sully was flying an A320.

[richard_smith237]

39 minutes ago, Phillip9 said:

 

On a 737 the only accumulator is for braking.  The engines normally produce the hydraulic pressure.  If both engines are out, you will immediately have no hydraulics and no electronics.  The 737 can be flown with no hydraulics because it has back up manual control cables.

 

There is a back up electric generator, but that takes time to deploy.  That will give you electronics.  Then there are back up electric hydraulic pumps that will restore hydraulics.  That's what Sully did.  

 

The Jeju plane was so low, that they likely did not have time to get through these steps to restore hydraulics and then lower the gear and flaps.

 

 

In all fairness to the pilots, they didn't 'need' to..... (in an emergency situation like this).

 

Had there been standard ILS eqipment at the end of the runway and not a huge bern with thick concrete slab, the flight would have continued on through the thin breeze-block wall into the fields. 

 

According to other sources - Due to the approach speed and no flaps, the ground effect was greater than normal, thus the buffeting from the ground resulted in a touchdown halfway down the runway, but the pilot executed an excellent no gear touchdown.

 

Its possible there would have been no fatalities, had the berm wall not been present - aviation experts have suggest the presence of this berm wall borders on criminal.

 

 

 

 

[Phillip9]

22 minutes ago, nauseus said:

 

Sully was flying an A320.

 

After a failure of all engines, deploying the backup generator is necessary to restore electronics and other important systems in every modern commercial jet aircraft.

[nauseus]

2 hours ago, Harsh Jones said:

 

All airliners have hydraulic nitrogen accumulators that store pressurized fluid and provide backup power for various systems. Both engines could fall off mid flight and they would have hydraulics for hours. 

 

Hydraulic systems: Accumulators operate the main hydraulic system and the emergency system. 

 

Landing gear: Accumulators provide backup power for the landing gear. 

 

Brakes: Accumulators provide backup power for the brakes. 

 

Emergency applications: Accumulators provide backup power for emergency applications. 

 

 

 

 

In the 737 accumulators only serve the braking system and can still work in the case of main hydraulic system failure. 

 

If the gear is up then no wheel brakes available anyway.

[nauseus]

6 minutes ago, richard_smith237 said:

 

In all fairness to the pilots, they didn't 'need' to..... (in an emergency situation like this).

 

Had there been standard ILS eqipment at the end of the runway and not a huge bern with thick concrete slab, the flight would have continued on through the thin breeze-block wall into the fields. 

 

According to other sources - Due to the approach speed and no flaps, the ground effect was greater than normal, thus the buffeting from the ground resulted in a touchdown halfway down the runway, but the pilot executed an excellent no gear touchdown.

 

Its possible there would have been no fatalities, had the berm wall not been present - aviation experts have suggest the presence of this berm wall borders on criminal.

 

 

 

 

 

Yes. The localizer looked standard but the reinforced concrete berm was not, at least in most countries. 

 

Most civil airports in the ROK are also intended to be suitable for joint military use but not sure if that is meaningful in this case. 

[richard_smith237]

8 minutes ago, Phillip9 said:

After a failure of all engines, deploying the backup generator is necessary to restore electronics and other important systems in every modern aircraft.

 

The 737-800 has batteries which last approximately 30 minutes to control critical systems.

 

The Hydraulic Systems for Flaps: 

Primary Operation:

- The flaps and slats on the 737 are powered by Hydraulic System B during normal operation.

- Hydraulic System B relies on engine-driven pumps or electric motor-driven pumps.

Electric Motor-Driven Pumps:

- If both engines fail, the electric hydraulic pumps can still power Hydraulic System B, provided electrical power is available (e.g., from the aircraft's batteries, APU, or other backup sources like a Ram Air Turbine on some aircraft types).

Standby Hydraulic System:

- The 737's standby hydraulic system can also operate the leading-edge slats and flaps if both primary hydraulic systems (A and B) are unavailable.

 

Thus: there are two redundancies for the flaps. 

 

 

In the event of dual engine failure and thus, loss of power, the hydraulic systems (flaps) run (initially) on Electric Motor-driven pumps, powered by the air-crafts batteries, for approximately 30 minutes. 

 

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.

 

the electric 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: for no flaps to be deployed, either there was total hydraulic and electrical failure, or, I hesitate to say, there was a degree of pilot error in not turning on the electric motor-driven hydraulic pumps.

In which case there the aircraft would face significant operational challenges, including difficulty in extending flaps, slats, and landing gear, as well as reduced control effectiveness.

 

One would assume that pilot training emphasises the importance of promptly managing hydraulic and electrical systems in emergencies to maintain aircraft control and ensure a safe landing.

 

But, for some reason the flaps, slats and landing gear were not extended. 

 

[richard_smith237]

5 minutes ago, nauseus said:

 

Yes. The localizer looked standard but the reinforced concrete berm was not, at least in most countries. 

 

Most civil airports in the ROK are also intended to be suitable for joint military use but not sure if that is meaningful in this case. 

 

I thought of military reasons, and the only one I can think of is a 'jet blast wall' - but, that would look somewhat different and they are not usually on the runways, but closer to terminal buildings and hangars. 

 

This airport opened in 2007 and there appears to be no military looking hangars etc around the airport, not that this means anything - as the airport could still be 'military ready', but I don't think the 'berm wall' has any relation to potentail military activity.

 

I think its just a tragic mistake to build the 'berm wall' like that - I'm sure there are other airports around the world whereby, right at this moment, are re-engineering any structures such as this at the end of their runways. 

 

 

It's even possible, that in the 'mother of all stuff-ups' the 'berm wall' was built in the manner it was, though nothing other than a simple mistake - i.e. (speculation) the ALS lighting and equipment did not have sufficient height (and it was going to take a while to get new parts to extend it) the solution was to build the berm and place a base on it so the ALS equipment was level and at the right height (i.e. same height as the runway).

That is pure speculation of course - but the only reason I can think of to have that 'berm wall' there.

 

 

 

 

[nauseus]

23 minutes ago, Phillip9 said:

 

After a failure of all engines, deploying the backup generator is necessary to restore electronics and other important systems in every modern aircraft.

 

The APU has limited use in the air. But as Denys said in his VDO, it takes some time to run up and some reconfiguration would be required. It looks like, for whatever reason, the pilots had little or no time for this, unfortunately.  

[richard_smith237]

4 minutes ago, nauseus said:

31 minutes ago, Phillip9 said:

 

After a failure of all engines, deploying the backup generator is necessary to restore electronics and other important systems in every modern aircraft.

 

The APU has limited use in the air. But as Denys said in his VDO, it takes some time to run up and some reconfiguration would be required. It looks like, for whatever reason, the pilots had little or no time for this, unfortunately.  

 

The APU is a red herring in this cause - there are electric-motor driven pumps which can operate for approximately 30minutes after loss of both engines (apparently the switch over is instantaneous).

 

... the caveat - if it was working, there was perhaps multiple catastrophic failures which led to a non-flaps, high speed landing without gear.....  resulting in significant 'ground effect' due to the speed and a later 'belly touch down' than intended. 

 

 

 

 

[nauseus]

35 minutes ago, richard_smith237 said:

 

The APU is a red herring in this cause - there are electric-motor driven pumps which can operate for approximately 30minutes after loss of both engines (apparently the switch over is instantaneous).

 

... the caveat - if it was working, there was perhaps multiple catastrophic failures which led to a non-flaps, high speed landing without gear.....  resulting in significant 'ground effect' due to the speed and a later 'belly touch down' than intended. 

 

 

 

 

 

Well whatever the colour of the fish may be, there would have been time needed to reconfigure - it looks like they didn't have that. 

[Harsh Jones]

1 hour ago, Moonlover said:

So I'll assume from this post that you are now conceding that there is a possibility that there was a double engine failure.

 

Personally, I am convinced that it was a double engine failure. And that conviction comes not from all the technical arguments, but from the pilot's actions, especially his radio transmission. If the aircraft had suffered a single engine failure, he would have made a 'PAN-PAN' call and followed air traffics instructions to make a second landing attempt. 

 

But he didn't. He declared 'MAYDAY-MAYDAY'. That screams at me a double engine failure. 'Get me on ground NOW!'

 

I shall await, with interest, the results of the enquiry.

 

Even if there was a dual engine failure on final, the procedure is not to panic land the aircraft like they did. That is just not how any of this works. Ever. This is why every pilot on Youtube is just lost for words about this incident. 

 

There was a Canadian airliner years ago that ran out of fuel. It glided for 120 kilometers and landed without incident. There was an airliner with a dual engine bird strike and failure in Russia recently. They glided the plane 1 kilometer from the airport into a field. Slamming the aircraft down onto the ground on the last 3rd of the runway, not giving yourself enough distance to slow down is not an acceptable plan under pretty much any circumstance. 

 

 

 

 

[Nick Carter icp]

3 minutes ago, Harsh Jones said:

. Slamming the aircraft down onto the ground on the last 3rd of the runway, not giving yourself enough distance to slow down is not an acceptable plan under pretty much any circumstance. 

 

 

   Could be that they didn't have any other choice ?

[richard_smith237]

7 minutes ago, nauseus said:

Well whatever the colour of the fish may be, there would have been time needed to reconfigure - it looks like they didn't have that. 

 

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).

 

 

 

[richard_smith237]

6 minutes ago, Nick Carter icp said:

10 minutes ago, Harsh Jones said:

. Slamming the aircraft down onto the ground on the last 3rd of the runway, not giving yourself enough distance to slow down is not an acceptable plan under pretty much any circumstance. 

   Could be that they didn't have any other choice ?

 

In response to Harsh Jones comment.

 

The aircraft was not 'slammed down' - in-fact the belly landing was executed almost perfectly.

 

Almost, as one of the issues was the air-craft touching down halfway down the runway - the reason for this is 'ground effect' - whereby at higher groundspeed the cushion of 'air' was greater.

 

Unless pilots are also trained to fly dedicated wing-in ground effect craft, this is something they are not familiar with. 

 

Thus: the combination of higher speed, no landing gear, no flaps and ground effect resulted in touch-down further down the runway that the pilots would have anticipated. 

 

Additionally, the pilots may not have been able to 'test' the ground effect before the runway and 'get the feel' to touch down at the start of the runway as this could have led to a premature touchdown and undershoot the runway. 

 

 

 

 

[nauseus]

3 minutes ago, 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).

 

 

 

 

Power might be instantly available but electrical power to the hydraulics takes time to take effect and operation is slow.

 

Suggest you have another look at this VDO from Denys - also with reference to the APU.

 

 

[richard_smith237]

17 minutes ago, Harsh Jones said:

Even if there was a dual engine failure on final, the procedure is not to panic land the aircraft like they did. That is just not how any of this works. Ever. This is why every pilot on Youtube is just lost for words about this incident. 

 

There was a Canadian airliner years ago that ran out of fuel. It glided for 120 kilometers and landed without incident. There was an airliner with a dual engine bird strike and failure in Russia recently. They glided the plane 1 kilometer from the airport into a field. Slamming the aircraft down onto the ground on the last 3rd of the runway, not giving yourself enough distance to slow down is not an acceptable plan under pretty much any circumstance. 

 

In both of your examples the flight crew had altitude and time to respond. 

 

The glide ratio of a 737-800 is 15:1... but without flaps the landing speed is going to be high and this was a primary issue, even without landing gear.

 

But... even with all of the issue, no flaps, no engines, no landing gear and a touchdown halfway down the runway -- it has been argued by experts that this crash was survivable, if it were not for the 'berm wall' at the end of the runway.

 

 

[Harsh Jones]

51 minutes ago, nauseus said:

 

The APU has limited use in the air. But as Denys said in his VDO, it takes some time to run up and some reconfiguration would be required. It looks like, for whatever reason, the pilots had little or no time for this, unfortunately.  

There is no circumstance where doing what they did was the proper procedural course of action. (other than fire) That is the problem. 

 

 

People keep bringing up a dual engine failure when we are just using that for arguments sake. It is much more likely that it was not a dual engine failure. 

[Harsh Jones]

24 minutes ago, Nick Carter icp said:

 

   Could be that they didn't have any other choice ?

 

No. Unless the cockpit was literally on fire, no. 

 

 

[Nick Carter icp]

3 minutes ago, Harsh Jones said:

 

No. Unless the cockpit was literally on fire, no. 

 

 

 

   Are you qualified to make that claim ?

[richard_smith237]

7 minutes ago, nauseus said:

 

Power might be instantly available but electrical power to the hydraulics takes time to take effect and operation is slow.

 

Suggest you have another look at this VDO from Denys - also with reference to the APU.

 

 

The video is excellent and highly informative...  

 

What I have read, is that the switchover to the electric-driven pumps is effectively instantaneous if the electric pumps are already activated. 

 

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.

 

 

Also what I have read, it takes about 1-2 minutes to switch over to relying on power from the APU - so there was no time and altitude for that - the battery power is designed to bridge the gap. 

 

Thus: based on what I have read: Theoretically - back-up hydraulic power is instantaneous. 

 

 

Thus 3 potential possibilities: 

 

1) Back-up is no instantaneous (and what I have read is incorrect)

2) There was a catastrophic failure of backup systems

3) Pilot error - electric-motor hydraulic pumps were not engaged.

 

 

 

Note: this is an interesting discussion. RIP to the pilots,  I don't mean any disrespect to them.

However, for the purposes of the discussion on this thread, all possibilities can be considered - and yes, of course, we are all laymen, but that does not mean interesting discussion cannot take place (after all this is what the forum is designed for).