Jeju Air737-800 Crash at MWX (Muan International Airport, South Korea)

[B_C]

... btw, since I am a jetphotos member, I know one quite famous belly landing, with even zero injuries, all 231 souls on board survive.

https://en.wikipedia.org/wiki/LOT_Polish_Airlines_Flight_16

But somewhere there is a difference to the 738 which we talk about today:



Or how old was the 738 Cpt here in this case?

Here it is,Captain Han was a 45-year-old pilot who had previously served in the Air Force and had over 6,800 hours of flight time under his belt. Serving as a captain for the past five years, Captain Han was known among his peers for his professionalism and unwavering commitment to safety.

https://www.koreaboo.com/news/colleagues-disclose-details-jeju-air-pilot-involved-in-tragic-crash/

[bstolle]

they turned nicely to runway 19 and landed smoothly on the runway. looks like they still at least have some hydraulic powers generated from the engines. but why they didn't apply flaps, spoilers and lower the landing gears? I don't understand.

Suggest to (re)read post 62 in this thread.

[thor]

Suggest to (re)read post 62 in this thread.

thanks. but could they survive if spoilers were fully deployed immediately after touch down?

[bstolle]

That's an interesting question and it will be difficult to calculate I assume. Gabriel might be able to come up with an approximation.

[Evan]

CNN is reporting that both flight recorders stopped recording 4 minutes before the crash. That suggests a second engine failure without APU and no RIPS equipped data recorders installed. This is a major setback and illustrates the need for a MANDATED retrofit to RIPS in the shortest practical timeframe. Hopefully there will be some QAR data but maybe of limited use here. What we really need to know is what the pilots were thinking and the CRM involved.

[Evan]

and where is this source material?

you can't cite sources and not provide the sources. unless of course your name is McCarthy

Am I seriously the only one here who knows how to do any research?

Page #4 in this document (#103 in the original document):

https://www.dcs.gla.ac.uk/~johnson/papers/seattle_hessd/judithlynne-p.pdf

Errors in Aviation Decision Making: A Factor in Accidents and Incidents Judith Orasanu Lynne Martin NASA-Ames Research Center
In addition to the reference to (Kahneman & Tversky, 1984) and the concept of 'framing' in the section titled Underestimating Risk, they mention something called 'frequency gambling' which occurs when pilots place decisive weight of what has been successful in numerous past instances over what it the safest course of action. This is key to understanding why total hours in the cockpit do not always align with safety.

Beginning on Page #5 of this document, you will find the Ames Research Study:

https://repository.gatech.edu/server/api/core/bitstreams/ceebd7c1-607b-4a19-b472-0671f9c759d1/content

OPERATIONAL FACTORS IN PILOTS’ RISK ASSESSMENT AND MANAGEMENT Ute Fischer Georgia Institute of Technology Judith Orasanu NASA Ames Research Center Jeannie Davison San Jose State University/NASA Ames Research Center
On page #7 you will find the section Decision frames as a possible cause of pilots’ plan-continuation errors which references (Tversky & Kahneman, 1981).

Again, this is a phenomena referenced in accident reports as well. The original Ames Reseach Center document where I first read about Tversky & Kahneman's framing phenomena is a scan of a type-written report presented to Ames in 1998, if I'm not mistaken. Good luck finding that.

[BoeingBobby]

thanks. but could they survive if spoilers were fully deployed immediately after touch down?

I seriously doubt it. Spoilers are not for SLOWING the aircraft down. They are there to reduce lift.

[Gabriel]

thanks. but could they survive if spoilers were fully deployed immediately after touch down?

It would have helped slow down. Survive? Hard to say.

That's an interesting question and it will be difficult to calculate I assume. Gabriel might be able to come up with an approximation.

I failed at calculating the deceleration rate as shown in the video so I can't "adjust" that by the increased friction that the spoilers would have helped produce.

I seriously doubt it. Spoilers are not for SLOWING the aircraft down. They are there to reduce lift.

On the contrary, spoilers are CRITICAL to slow the planes down. It's just indirect.
They kill lift ("reduce" is an understatement, they can even make lift negative) so they massively increase the weight-on-wheels (or in this case the weight on engine nacelles and rear fuselage), and the friction force is directly proportional to the weight-on-wheels (the correct term is Normal force). In that way, except in cases where the traction with the runway is negligible (like wet ice), the availability or lack of spoilers have much, much more effect than the reversers on the ability of the plane to decelerate, especially at high speeds (at low speeds lift is small anyway without spoilers).

A large number of accidents happened due to spoilers not being deployed.

[Gabriel]

CNN is reporting that both flight recorders stopped recording 4 minutes before the crash. That suggests a second engine failure without APU and no RIPS equipped data recorders installed. This is a major setback and illustrates the need for a MANDATED retrofit to RIPS in the shortest practical timeframe. Hopefully there will be some QAR data but maybe of limited use here. What we really need to know is what the pilots were thinking and the CRM involved.

Damn, sometimes I am right, and some of those times I hate to be right.

I don't have a lot of hopes in the QAR or other avionics with internal memory. They are all situated towards the front of the plane and they are not crash, fire and water -protected like the black boxes. I don't think they would survive a direct crash against a reinforced-concrete-reinforced embankment and subsequent fire and subsequent water from the firefighting.

We will probably never know why the landing gear, flaps and spoilers were not extended.
We know they lost both electrical systems. We will probably never know how much thrust the engines kept producing (for example was it just a generator failure in one of the engines?). It seems that #2 was at least running at touchdown, but we will likely never know in what condition it was.

I hope that they can make a better analysis of the video that I did to tell exactly where it touched down, at what speed, and what was the speed and acceleration along the run.
I am wondering if they had a significant forward thrust still active after touchdown.

[BoeingBobby]

It would have helped slow down. Survive? Hard to say.


I failed at calculating the deceleration rate as shown in the video so I can't "adjust" that by the increased friction that the spoilers would have helped produce.


On the contrary, spoilers are CRITICAL to slow the planes down. It's just indirect.
They kill lift ("reduce" is an understatement, they can even make lift negative) so they massively increase the weight-on-wheels (or in this case the weight on engine nacelles and rear fuselage), and the friction force is directly proportional to the weight-on-wheels (the correct term is Normal force). In that way, except in cases where the traction with the runway is negligible (like wet ice), the availability or lack of spoilers have much, much more effect than the reversers on the ability of the plane to decelerate, especially at high speeds (at low speeds lift is small anyway without spoilers).

A large number of accidents happened due to spoilers not being deployed.

If you say so. I was talking about THIS aircraft. On the asphalt with no gear and no flaps.But I am probably just lying about my experience anyway.

[Gabriel]

If you say so. I was talking about THIS aircraft. On the asphalt with no gear and no flaps.

So was I. In this aircraft, with no gear and no flaps, the lift would still have been significantly reduced by the application of spoilers. Even if the lift was already small (due to the low lift coefficient for a flapless wing at low angle-of-attack), zero is the limit when it comes to reducing lift. It can (and mostly certainly would have) become negative with spoilers, thus increasing the force with which the engines and aft belly were pressing on the asphalt and hence massively increasing the friction force.

But I am probably just lying about my experience anyway.

I don't know what you are talking about. I hope you didn't read my statement as me questioning your experience in any way, shape or form, because I don't question it. And I don't know what your experience would have to do with this anyway. I hope that you, in your dozens of thousands of hours, didn't have the chance to slide an airplanes gear up on the asphalt at least two times, one with and one without spoilers, as to have experienced the difference.

[Evan]

Damn, sometimes I am right, and some of those times I hate to be right.

I don't have a lot of hopes in the QAR or other avionics with internal memory. They are all situated towards the front of the plane and they are not crash, fire and water -protected like the black boxes. I don't think they would survive a direct crash against a reinforced-concrete-reinforced embankment and subsequent fire and subsequent water from the firefighting.

We will probably never know why the landing gear, flaps and spoilers were not extended.
We know they lost both electrical systems. We will probably never know how much thrust the engines kept producing (for example was it just a generator failure in one of the engines?). It seems that #2 was at least running at touchdown, but we will likely never know in what condition it was.

I hope that they can make a better analysis of the video that I did to tell exactly where it touched down, at what speed, and what was the speed and acceleration along the run.
I am wondering if they had a significant forward thrust still active after touchdown.

Regarding the QAR (if there is any), all they would need to recover is the actual memory chip, which should survive a catastrophic crash but not a fire. But it won't tell us what they were thinking and saying or doing during those critical four minutes. I guess nothing will now.

The what is fairly obvious: multiple bird strikes and engine failures in a bird-strike-prone environment, leading to a desperately time-compressed must-land situation. The purpose of investigations is to help prevent future occurrences, so what can be done here?

• For starters, I would write or revise procedure for bird (flock) strike with engine failure** to instruct pilots to expect additional engine strikes and continue the landing if they can safely do so. LAND ASAP.
• I would also enhance efforts to find better solutions for bird strike avoidance, including methods to keep birds away and establishing conditions where the aerodrome must be temporarily closed when they are present. Flocks of birds in the flightpath isn't much safer than CB's over it. GO AROUND or DIVERT.
• And then, of course, strengthen CRM within the airline culture, and practice this scenario in the SIM. But there is a limit to what level of human performance can be relied upon in this scenario. It's best to avoid it at all costs.
• Maybe revise airport requirements to prohibit a large obstacle at the end of the overrun. If you must (in this case, I've read that it was needed to elevate the ILS array) make it frangible, to absorb the energy and stop the plane in a more survivable way. However, I realize the fatal error here was in landing halfway down the runway, and not much can be done to deal with that scenario.

** This procedure would be applied where pilots have been advised of the presence of birds (plural) near the flightpath. In the briefing: "if we hit birds and lose an engine, we continue" or something along those lines.

[BoeingBobby]

So was I. In this aircraft, with no gear and no flaps, the lift would still have been significantly reduced by the application of spoilers. Even if the lift was already small (due to the low lift coefficient for a flapless wing at low angle-of-attack), zero is the limit when it comes to reducing lift. It can (and mostly certainly would have) become negative with spoilers, thus increasing the force with which the engines and aft belly were pressing on the asphalt and hence massively increasing the friction force.



I don't know what you are talking about. I hope you didn't read my statement as me questioning your experience in any way, shape or form, because I don't question it. And I don't know what your experience would have to do with this anyway. I hope that you, in your dozens of thousands of hours, didn't have the chance to slide an airplanes gear up on the asphalt at least two times, one with and one without spoilers, as to have experienced the difference.

When it be slidin down da runway on her belly, ain't much lift being produced at dat point. If you think that spoiler extension would have saved their ass, I ain't gettin in no flying machine wit you been doing da flying!

[Evan]

When it be slidin down da runway on her belly, ain't much lift being produced at dat point.

Da wing is producing lift if the AoA and airspeed are favorable for lift. Both are favorable for lift in this case, I think even up to the impact.

I'm not sure how much added drag is produced here. The friction of nacelles (CFRP?) on concrete is considerable, but is it much greater than locked-up tires on concrete? Remember, antiskid (keeping the tires rolling) shortens stopping distance...

[BoeingBobby]

Da wing is producing lift if the AoA and airspeed are favorable for lift. Both are favorable for lift in this case, I think even up to the impact.

I'm not sure how much added drag is produced here. The friction of nacelles (CFRP?) on concrete is considerable, but is it much greater than locked-up tires on concrete? Remember, antiskid (keeping the tires rolling) shortens stopping distance...

Not enough to compensate for the amount of drag. Again as I asked Gabe, do you ou think the deployment of spoilers would have made a significant difference?