B737 Crashes on landing in South Korea

[RiNCEw1ND]

The 737 family main battery has been a 40 Ah Nicad battery since day One. It's rated at the 1 hour rate i.e 40 Amps for 1 hour to 20 Volts at 25 °C. The standby electrical system must provide power for 1 hour maximum the enable the aircraft to land safely. Remember that the diversion fuel is 45 minutes max.
The Essential Buss will be powered by the main battery.

They're using Ni-Cads at about 53 Ah rated now, and I think they are supposed to be high 40s end of life. The NGs can have a second identical Aux battery as well depending on mod status. As an aside, there are STCs available to use lead acids in both the NGs and classics instead, this is the STC I have seen them using (38 Ah - Classic): https://batterymanagement.concordebatte ... 4%20HR.pdf
( 48Ah - NG) https://batterymanagement.concordebatte ... 4%20HR.pdf

So it is a little more blurred than the Ni-Cads from day one.

[Patrick AL]

Thankfully good sense prevails, and I expect thousands of airports worldwide will be scrutinising and upgrading their over-run zones to mitigate risk where possible.

-arrestor beds, engineered catchfences and thin fragile boundary walls should improve chances vastly for incidents such as this.

https://www.bbc.com/news/articles/c0e4qgj41g8o


South Korea will change the concrete barriers used for navigation at seven airports across the country following December's plane crash that killed 179 people.

Seven airports will also have their runway safety areas adapted following a review of all South Korea's airports that was carried out after the crash - the deadliest in the country's history.

The Jeju Air flight was bringing passengers home from Thailand after Christmas when it made an emergency landing at Muan airport and exploded after slamming into a concrete barrier at the end of the runway.

The cause of the crash is still unknown but air safety experts had earlier said the number of casualties could have been much lower if not for the structure.

The concrete structure holds a navigation system that assists aircraft landings - known as a localiser. South Korea's transport ministry had said this system could also be found in other airports in the country and even overseas.

Safety inspectors have now identified nine of these systems, which they say need to be altered. These include the systems at Muan and Jeju International Airport which is the country's second-largest airport.

They are looking to either replace the concrete bases with more lightweight structures or bury them underground.

Officials added that Muan International Airport's existing concrete mounds would be removed entirely and the localiser "reinstalled using breakable structures".

Following the crash, it emerged that an operating manual from Muan International Airport, uploaded early in 2024, had said the concrete embankment was too close to the end of the runway.

The document, prepared by Korea Airports Corp, had recommended the location of the equipment be reviewed during a planned expansion.

Chris Kingswood, a pilot with 48 years' experience who has flown the same type of aircraft involved in the crash, previously told the BBC that "obstacles within a certain range and distance of the runway are required to be frangible, which means that if an aircraft strikes them that they do break.

[Brand Wessels]

All smoke 'n mirrors. They have no choice - public perception management is a big deal.

The reality is that when any airliner skids off the end of any runway at such high speed, it is highly likely to end in complete disaster. No matter how large, small or "soft" the "over-run" area will be.

It is not like there will suddenly be a lot more space at the end of all runways.

Maybe the death toll could have been less - it is a miracle there were two survivors. If it left the airport perimeter (and it most certainly would have) the fatalities could have been more as well. It is all conjecture.

Nobody in their right mind should be hoping or planning for a good outcome under these circumstances - anything but a smooth runway is not a realistic option. Airliners do not crash well.

The only real option is to not end up in these circumstances - once you are there you roll the dice and hope to survive. No ammount of engineering/design or planning will guarantee any less fatalities.

[Brand Wessels]

All smoke 'n mirrors. They have no choice - public perception management is a big deal.

The reality is that when any airliner skids off the end of any runway at such high speed, it is highly likely to end in complete disaster. No matter how large, small or "soft" the "over-run" area will be.

It is not like there will suddenly be a lot more space at the end of all runways.

EMAS systems actually work remarkably well, and will stop a fully loaded airliner from 70kts in less distance than that. BUT the gear must be down for them to work effectively, so would not have made too much difference in this case.

[Patrick AL]

All smoke 'n mirrors. They have no choice - public perception management is a big deal.

The reality is that when any airliner skids off the end of any runway at such high speed, it is highly likely to end in complete disaster. No matter how large, small or "soft" the "over-run" area will be.

It is not like there will suddenly be a lot more space at the end of all runways.

Maybe the death toll could have been less - it is a miracle there were two survivors. If it left the airport perimeter (and it must certainly would have) the fatalities could have been more as well. It is all conjecture.

Nobody in their right mind should be hoping or planning for a good outcome under these circumstances - anything but a smooth runway is not a realistic option. Airliners do not crash well.

The only real option is to not end up in these circumstances - once you are there you roll the dice and hope to survive. No ammount of engineering/design or planning will guarantee any less fatalities.

Nonsense!

[Brand Wessels]

All smoke 'n mirrors. They have no choice - public perception management is a big deal.

The reality is that when any airliner skids off the end of any runway at such high speed, it is highly likely to end in complete disaster. No matter how large, small or "soft" the "over-run" area will be.

It is not like there will suddenly be a lot more space at the end of all runways.

Maybe the death toll could have been less - it is a miracle there were two survivors. If it left the airport perimeter (and it must certainly would have) the fatalities could have been more as well. It is all conjecture.

Nobody in their right mind should be hoping or planning for a good outcome under these circumstances - anything but a smooth runway is not a realistic option. Airliners do not crash well.

The only real option is to not end up in these circumstances - once you are there you roll the dice and hope to survive. No ammount of engineering/design or planning will guarantee any less fatalities.

Nonsense!

Cool. No undercarriage, no brakes, no flaps, no spoilers, no operational reverse thrust, landing 1200m from the threshold, skidding off the end of the runway, on the fuselage, still at 150 knots. I think they had very little, if any chance of survival.

But yes, that is just my opinion. Nonsense as it apparently is.

[Patrick AL]

All smoke 'n mirrors. They have no choice - public perception management is a big deal.
Not smoke 'n mirrors at all -it is an entirely practical solution to the real problem we saw demonstrated in the incident -safety and related considerations are in every user's interest -including pilots/crew -not just a matter of 'public perception' at all

The reality is that when any airliner skids off the end of any runway at such high speed, it is highly likely to end in complete disaster. No matter how large, small or "soft" the "over-run" area will be.
Not at all a 'reality' -by my understanding of dynamics and basic energy dissipation etc.-the more mitigating factors ( clear airside over-run, 'soft structures/fences, clear area beyond airside over-run, etc., will all vastly increase chances of survivable accident

It is not like there will suddenly be a lot more space at the end of all runways.
certainly -but the idea is to mitigate in any way possible, and in as many ways as are possible -depending on the specific airport parameters,of course

Maybe the death toll could have been less - it is a miracle there were two survivors. If it left the airport perimeter (and it must certainly would have) the fatalities could have been more as well. It is all conjecture.
It's a disaster that there were only 2 survivors -I think it is pretty certain that had the berm not been there, and the aircraft went through the block wall and into the fairly open zone beyond, there would certainly have been many more survivors, if not all crew/passengers


Nobody in their right mind should be hoping or planning for a good outcome under these circumstances - anything but a smooth runway is not a realistic option. Airliners do not crash well.

?-I am guessing, despite all possible things that could go wrong, one still plans and hopes for as good an outcome as possible -definitely not writing off one's chances just because they may be lean/ less than very promising

The only real option is to not end up in these circumstances - once you are there you roll the dice and hope to survive. No ammount of engineering/design or planning will guarantee any less fatalities.

But aircraft do and will end up in these situations - any of thousands of engineering/design solutions work every day to prevent accidents and fatalities -and we rely on these every day- in aviation, or in simply climbing a ladder.
Disregarding the risk posed by of one slippery/loose rung of a ladder -because the user may fall by mis-aligning a ladder anyhow -is entirely illogical

Apologies for short blanket reply earlier -not meaning to simply write your input off entirely- but did not have time earlier to detail why I think it is mostly nonsense.
See my comments in bold per point of your post..

[StressMerchant]

Nonsense!

Cool. No undercarriage, no brakes, no flaps, no spoilers, no operational reverse thrust, landing 1200m from the threshold, skidding off the end if the runway, on the fuselage, still at 150 knots. I think they had very little, if any chance of survival.

But yes, that is just my opinion. Nonsense as it apparently is.

As far as the FAA aircraft design rules are concerned, any excursion from the runway at greater than 60 knots is considered catastrophic. The probability requirements of 14 CFR 25.1309(b) will apply.

[Brand Wessels]

All smoke 'n mirrors. They have no choice - public perception management is a big deal.
Not smoke 'n mirrors at all -it is an entirely practical solution to the real problem we saw demonstrated in the incident -safety and related considerations are in every user's interest -including pilots/crew -not just a matter of 'public perception' at all

The reality is that when any airliner skids off the end of any runway at such high speed, it is highly likely to end in complete disaster. No matter how large, small or "soft" the "over-run" area will be.
Not at all a 'reality' -by my understanding of dynamics and basic energy dissipation etc.-the more mitigating factors ( clear airside over-run, 'soft structures/fences, clear area beyond airside over-run, etc., will all vastly increase chances of survivable accident

It is not like there will suddenly be a lot more space at the end of all runways.
certainly -but the idea is to mitigate in any way possible, and in as many ways as are possible -depending on the specific airport parameters,of course

Maybe the death toll could have been less - it is a miracle there were two survivors. If it left the airport perimeter (and it must certainly would have) the fatalities could have been more as well. It is all conjecture.
It's a disaster that there were only 2 survivors -I think it is pretty certain that had the berm not been there, and the aircraft went through the block wall and into the fairly open zone beyond, there would certainly have been many more survivors, if not all crew/passengers


Nobody in their right mind should be hoping or planning for a good outcome under these circumstances - anything but a smooth runway is not a realistic option. Airliners do not crash well.

?-I am guessing, despite all possible things that could go wrong, one still plans and hopes for as good an outcome as possible -definitely not writing off one's chances just because they may be lean/ less than very promising

The only real option is to not end up in these circumstances - once you are there you roll the dice and hope to survive. No ammount of engineering/design or planning will guarantee any less fatalities.

But aircraft do and will end up in these situations - any of thousands of engineering/design solutions work every day to prevent accidents and fatalities -and we rely on these every day- in aviation, or in simply climbing a ladder.
Disregarding the risk posed by of one slippery/loose rung of a ladder -because the user may fall by mis-aligning a ladder anyhow -is entirely illogical

Apologies for short blanket reply earlier -not meaning to simply write your input off entirely- but did not have time earlier to detail why I think it is mostly nonsense.
See my comments in bold per point of your post..

Thank you for taking the time. I am rather more interested in the root cause (not the end-result) to this accident - hopefully the investigators have more clues to work with. For some reason it would seem that both engines were out of operation - multiple birds strikes on both (that has happened before), or one because of bird strike and one pilot error in shutting down a working engine (that has also happened before).Those seems high on the list of possibilities. I recently read somewhere that bird remains were found in both engines?

Not dropping the undercarriage manually, will probably fall under human error. It seems fair to say that those last 4 minutes were a sudden and extreme stress-level occurrence at low level. The pilot flying obviously felt he had to land immediately, no matter what the speed or aircraft configuration was.

I am glad I was not in their shoes.

[Jasondn78]

Former chief of state-run airport firm found dead

A former head of the state-run Korea Airports Corp. , who was in office during the renovation of an instrument landing system localizer at Muan International Airport, was found dead at his home, police said Tuesday.

Police said they are investigating the cause of death of Son Chang-wan, who led the company from 2018 to 2022.

Last month, a Jeju Air B737-800 aircraft crashed at the airport, located some 290 kilometers southwest of Seoul, killing 179 people after skidding without its landing gear extended and colliding with the localizer.

The localizer, installed on a concrete structure, has been blamed for worsening the severity of the casualties. The airport underwent a renovation of the structure in 2020.

https://m.koreatimes.co.kr/pages/articl ... ce=taboola

[Vogoff]

Nobody in their right mind should be hoping or planning for a good outcome under these circumstances - anything but a smooth runway is not a realistic option. Airliners do not crash well.

The only real option is to not end up in these circumstances - once you are there you roll the dice and hope to survive. No amount of engineering/design or planning will guarantee any less fatalities.

Nobody plans for an accident like this. A lot of safety engineering has to do with how we deal with the post-accident side effects when the unthinkable happens.

For example - I have been a passenger in cars all my life and have never been in an accident that requires a seatbelt. And yet I wear my seatbelt every time I get in the car. Why? Because of that one time when the unthinkable happens and I do need it. The seatbelt doesn't care why there was an accident or whose fault it was, its one job is to improve my *chances* of surviving an accident without serious injuries.

This berm did not cause the accident. But by acting as an aircraft shredder it turned something that *might* have been survivable into something that definitely was not. While fatal accidents are often caused by things out of our control this particular hazard was a known risk and should have been addressed. Sure the crash may have still had the same result - but why stack the odds against survival?

The rush to fix it at other airfields is obviously driven by the embarrassment this error has caused, the problem is now in the public consciousness. Sadly it sometimes takes a disaster like this before people understand the seriousness of the issue. There are probably a dozen other safety findings that still won't be addressed because they aren't in the spotlight. Yes it is a case of closing the stable door after the horse has bolted - but it is still a good thing that it is being fixed.

It doesn't tell us how the accident happened. But we do know why a bad situation turned into a terrifying one and there is a lesson here: if you ignore safety issues for long enough then chances are you will find out one day why that safety issue matters.

[Drewdel]

I think that time is going to be the critical factor in this accident. Whether a single or dual engine bird strike occurred, whether those strikes were significant enough to disable both hydraulics systems, or if the incorrect engine was shut down is yet to be known.

But the bottom line is they landed belly up in a clean configuration, in a hurry. And that decision was taken at at a very low altitude.

The fact that they managed a wings level landing, albeit deep, is remarkable. That they found an obstacle in their path is regrettable, and only have increased the inevitability of a high fatality.

Given time, the crew would have been able to make a lot more use of the redundancy which the 737 has for at least a better landing configuration. But there was no time.

Whatever happened, I just think they were doomed by a low alt emergency and did what they could, well. IMHO

[Patrick AL]

https://www.bbc.com/news/articles/c5y6j32p7lxo


Investigators say they have found evidence of a bird strike on a passenger plane that crashed in South Korea in December, killing 179 people.

The feathers and blood stains on both engines of the Jeju Air plane were from the Baikal teal, a type of migratory duck that flies in large flocks, according to a preliminary investigation report published on Monday.

The inquiry into the crash - the deadliest on South Korean soil - will now focus on the role of the bird strike and a concrete structure at the end of the runway, which the plane crashed into.

The engines of the Boeing 737-800 will be torn down and the concrete structure will be examined further, the report said.

The Jeju Air plane took off from Bangkok in the morning of 29 December and was flying to Muan International Airport in the country's south-west.

At about 08:57 local time, three minutes after pilots made contact with the airport, the control tower advised the crew to be cautious of "bird activity".

At 08:59, the pilot reported that the plane had struck a bird and declared a mayday signal.

The pilot then requested permission to land from the opposite direction, during which it belly-landed without its landing gear deployed. It overran the runway and exploded after slamming into the concrete structure, the report said.
A graphic shows the final moments of Flight 7C2216 with the aircraft touching down with landing gear up on the runway near the airport. The photo below shows the Jeju Air plane skidding along the runway. The bottom image shows the aircraft in a dark cloud of debris as it hits an embankment.

Authorities earlier said that flight data and cockpit voice recorders from the plane stopped recording about four minutes before the disaster.

Experts who had flown the same type of aircraft involved in the crash have also questioned the presence of the concrete barriers at the end of the runway - with some suggesting that the casualty toll would have been lower if they had not been there.

The concrete structure holds a navigation system that assists aircraft landings, known as a localiser.

South Korea's transport ministry had said this system could also be found in other airports in the country and even overseas.

Last week, authorities announced that they will change the concrete barriers used for navigation at seven airports across the country. Seven airports will also have their runway safety areas adapted following a review.

The preliminary report has been submitted to the United Nations' aviation agency and to the authorities of the United States, France and Thailand.
A composite image with photos showing the embankment off the end of the runway at Muan International Airport, the wreckage of the plane that crashed, and a graphic showing the runway and the 250-metre distance to the embankment.

[Jasondn78]

Here is the Preliminary Report issued by the Korean Authorities.

Bird Strike

The pilots identified a group of birds while approaching runway 01,
and a security camera filmed HL8088 coming close to a group of birds
during a go-around. Both engines were examined, and feathers and bird
blood stains were found on each. The samples were sent to specialized
organizations for DNA analysis, and a domestic organization identified
them as belonging to Baikal Teals.

HL8088-Preliminary-Report.pdf

[Jasondn78]

A little bit of Googling, and the Baikal Teal is quite a bit smaller than the Canadian Geese that hit the US Airways A320 in New York.

According to Wikipedia, the Baikal Teal weights about 1 pound. The Canadain geese have an average weight of 6-14 pounds. I think the engine manufacturers fire chicken carcasses into test engines when testing their durability of the engine against bird strikes. I's guessing the chicken is probably about double the weight of the Baikal Teal.